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Zambry NS, Awang MS, Hamzah HH, Mohamad AN, Khalid MF, Khim BK, Bustami Y, Jamaluddin NF, Ibrahim F, Aziah I, Abd Manaf A. A portable label-free electrochemical DNA biosensor for rapid detection of Salmonella Typhi. ANALYTICAL METHODS : ADVANCING METHODS AND APPLICATIONS 2024; 16:5254-5262. [PMID: 39011785 DOI: 10.1039/d4ay00888j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/17/2024]
Abstract
A highly accurate, rapid, portable, and robust platform for detecting Salmonella enterica serovar Typhi (S. Typhi) is crucial for early-stage diagnosis of typhoid to avert and control the outbreaks of this pathogen, which threaten global public health. This study presents a proof-of-concept for our developed label-free electrochemical DNA biosensor system for S. Typhi detection, which employs a printed circuit board gold electrode (PCBGE), integrated with a portable potentiostat reader. Initially, the functionalized DNA biosensor and target detection were characterized using cyclic voltammetry (CV), differential pulse voltammetry (DPV), and electrochemical impedance spectroscopy (EIS) methods using a benchtop potentiostat. Interestingly, the newly developed DNA biosensor can identify target single-stranded DNA concentrations ranging from 10 nM to 20 μM, achieving a detection limit of 7.6 nM within a brief 5 minute timeframe. Under optimal detection conditions, the DNA biosensor exhibits remarkable selectivity, capable of distinguishing a single mismatch base pair from the target single-stranded DNA sequence. We then evaluated the feasibility of the developed DNA biosensor system as a diagnostic tool by detecting S. Typhi in 50 clinical samples using a portable potentiostat reader based on the DPV technique. Remarkably, the developed biosensor can distinctly distinguish between positive and negative samples, indicating that the miniaturised DNA biosensor system is practical for detecting S. Typhi in real biological samples. The developed DNA biosensor device in this work proves to be a promising point-of-care (POC) device for Salmonella detection due to its swift detection time, uncomplicated design, and streamlined workflow detection system.
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Affiliation(s)
- Nor Syafirah Zambry
- Centre for Innovation in Medical Engineering (CIME), Faculty of Engineering, Universiti Malaya, 50603 Kuala Lumpur, Malaysia
- Department of Biomedical Engineering, Faculty of Engineering, Universiti Malaya, 50603 Kuala Lumpur, Malaysia
- Institute for Research in Molecular Medicine (INFORMM), Health Campus, Universiti Sains Malaysia, 16150 Kubang Kerian, Kelantan, Malaysia
| | - Mohd Syafiq Awang
- Collaborative Microelectronic Design Excellence Center (CEDEC), Universiti Sains Malaysia, Sains@USM, Level 1, Block C, No. 10 Persiaran Bukit Jambul, 11900 Bayan Lepas, Pulau Pinang, Malaysia
| | - Hairul Hisham Hamzah
- School of Health & Life Sciences, Teesside University, Middlesbrough, Tees Valley, TS1 3BX, UK
- School of Chemical Sciences, Universiti Sains Malaysia, 11800 Minden, Pulau Pinang, Malaysia
| | - Ahmad Najib Mohamad
- Institute for Research in Molecular Medicine (INFORMM), Health Campus, Universiti Sains Malaysia, 16150 Kubang Kerian, Kelantan, Malaysia
| | - Muhammad Fazli Khalid
- Institute for Research in Molecular Medicine (INFORMM), Health Campus, Universiti Sains Malaysia, 16150 Kubang Kerian, Kelantan, Malaysia
| | - Beh Khi Khim
- Collaborative Microelectronic Design Excellence Center (CEDEC), Universiti Sains Malaysia, Sains@USM, Level 1, Block C, No. 10 Persiaran Bukit Jambul, 11900 Bayan Lepas, Pulau Pinang, Malaysia
| | - Yazmin Bustami
- School of Biological Sciences, Universiti Sains Malaysia, 11800 Minden, Pulau Pinang, Malaysia
| | - Nurul Fauzani Jamaluddin
- Centre for Innovation in Medical Engineering (CIME), Faculty of Engineering, Universiti Malaya, 50603 Kuala Lumpur, Malaysia
- Department of Biomedical Engineering, Faculty of Engineering, Universiti Malaya, 50603 Kuala Lumpur, Malaysia
| | - Fatimah Ibrahim
- Centre for Innovation in Medical Engineering (CIME), Faculty of Engineering, Universiti Malaya, 50603 Kuala Lumpur, Malaysia
- Department of Biomedical Engineering, Faculty of Engineering, Universiti Malaya, 50603 Kuala Lumpur, Malaysia
| | - Ismail Aziah
- Institute for Research in Molecular Medicine (INFORMM), Health Campus, Universiti Sains Malaysia, 16150 Kubang Kerian, Kelantan, Malaysia
| | - Asrulnizam Abd Manaf
- Collaborative Microelectronic Design Excellence Center (CEDEC), Universiti Sains Malaysia, Sains@USM, Level 1, Block C, No. 10 Persiaran Bukit Jambul, 11900 Bayan Lepas, Pulau Pinang, Malaysia
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Nurmawati S, Alam A, Djauhari H, Merati TP, Sudarmono P, Setiawaty V, Arlinda D, Sugiyono RI, Arief M, Hadi U, Aman AT, Lokida D, Gasem MH, Tjitra E, Liang CJ, Neal A, Kosasih H, Karyana M, Lau CY, Alisjahbana B. Clinical characteristics of enteric fever and performance of TUBEX TF IgM test in Indonesian hospitals. PLoS Negl Trop Dis 2024; 18:e0011848. [PMID: 39052692 PMCID: PMC11315288 DOI: 10.1371/journal.pntd.0011848] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2023] [Revised: 08/09/2024] [Accepted: 06/26/2024] [Indexed: 07/27/2024] Open
Abstract
BACKGROUND Accurate diagnosis of enteric fever is challenging, particularly in low- and middle-income countries, due to the overlap of clinical and laboratory features with other pathogens. To better understand the difficulties in enteric fever diagnosis, we evaluated the characteristics of patients clinically diagnosed with enteric fever and the real-world performance of TUBEX TF, one of the most used tests in Indonesia. METHODOLOGY/PRINCIPAL FINDINGS Patients were recruited through the AFIRE (Etiology of Acute Febrile Illness Requiring Hospitalization) study at eight Indonesian hospitals. Blood culture was performed for all patients, and TUBEX TF was performed for suspected enteric cases. Salmonella PCR and ELISA tests were performed at a reference lab. Sensitivity and specificity of TUBEX TF and IgM and IgG anti-S. Typhi ELISA were determined. Of 301 patients clinically diagnosed with enteric fever, 50 (16.6%) were confirmed by blood culture and/or PCR. Confirmed cases were mostly school-aged children presenting with fever, anorexia, dizziness and/or abdominal pain with normal leukocyte count or leukopenia. TUBEX TF demonstrated a sensitivity of 97.6% to 70.7% and specificity of 38.3% to 67.2% at cutoffs of 4 and 6, respectively. Acute IgG demonstrated the best sensitivity and specificity, at 90.7% and 82.7%, respectively, and the best ROC characteristics. CONCLUSIONS/SIGNIFICANCE A substantial proportion of enteric fever was misdiagnosed at all study hospitals, likely due to the overlap of clinical characteristics and lab parameters with those of other common pathogens. The TUBEX TF rapid serological assay demonstrated suboptimal performance in our setting and tended to over-diagnose enteric fever. The role of IgG from acute specimens for identification of enteric fever cases merits additional consideration.
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Affiliation(s)
- Syndi Nurmawati
- Indonesia Research Partnership on Infectious Diseases (INA-RESPOND), Central Jakarta, Indonesia
- Research Center for Care and Control of Infectious Disease, Universitas Padjadjaran, Bandung, Indonesia
| | - Anggraini Alam
- Indonesia Research Partnership on Infectious Diseases (INA-RESPOND), Central Jakarta, Indonesia
- Pediatric Department, Faculty of Medicine, Universitas Padjadjaran/Dr. Hasan Sadikin Hospital, Bandung, Indonesia
| | - Hofiya Djauhari
- Indonesia Research Partnership on Infectious Diseases (INA-RESPOND), Central Jakarta, Indonesia
- Research Center for Care and Control of Infectious Disease, Universitas Padjadjaran, Bandung, Indonesia
| | - Tuti P. Merati
- Indonesia Research Partnership on Infectious Diseases (INA-RESPOND), Central Jakarta, Indonesia
- Faculty of Medicine, Udayana University, Denpasar, Indonesia
| | - Pratiwi Sudarmono
- Indonesia Research Partnership on Infectious Diseases (INA-RESPOND), Central Jakarta, Indonesia
- Faculty of Medicine, Universitas Indonesia, Central Jakarta, Indonesia
| | - Vivi Setiawaty
- Indonesia Research Partnership on Infectious Diseases (INA-RESPOND), Central Jakarta, Indonesia
- Prof. Dr. Sulianti Saroso Infectious Disease Hospital, North Jakarta, Indonesia
| | - Dona Arlinda
- Indonesia Research Partnership on Infectious Diseases (INA-RESPOND), Central Jakarta, Indonesia
- Health Policy Agency, Ministry of Heath, Central Jakarta, Indonesia
| | - Retna Indah Sugiyono
- Indonesia Research Partnership on Infectious Diseases (INA-RESPOND), Central Jakarta, Indonesia
- Health Policy Agency, Ministry of Heath, Central Jakarta, Indonesia
| | - Mansyur Arief
- Indonesia Research Partnership on Infectious Diseases (INA-RESPOND), Central Jakarta, Indonesia
- Dr. Wahidin Sudirohusodo Hospital, Makassar, Indonesia
| | - Usman Hadi
- Indonesia Research Partnership on Infectious Diseases (INA-RESPOND), Central Jakarta, Indonesia
- Department of Internal Medicine, Faculty of Medicine, Universitas Airlangga/Dr. Soetomo General Academic Hospital, Surabaya, Indonesia
| | - Abu Tholib Aman
- Indonesia Research Partnership on Infectious Diseases (INA-RESPOND), Central Jakarta, Indonesia
- Dr. Sardjito General Hospital/Faculty of Medicine, Universitas Gadjah Mada, Sleman, Indonesia
| | - Dewi Lokida
- Indonesia Research Partnership on Infectious Diseases (INA-RESPOND), Central Jakarta, Indonesia
- Tangerang General Hospital, Tangerang, Indonesia
| | - M. Hussein Gasem
- Indonesia Research Partnership on Infectious Diseases (INA-RESPOND), Central Jakarta, Indonesia
- Dr. Kariadi General Hospital/Faculty of Medicine, Universitas Diponegoro, Semarang, Indonesia
| | - Emiliana Tjitra
- Indonesia Research Partnership on Infectious Diseases (INA-RESPOND), Central Jakarta, Indonesia
- Health Policy Agency, Ministry of Heath, Central Jakarta, Indonesia
| | - C. Jason Liang
- Indonesia Research Partnership on Infectious Diseases (INA-RESPOND), Central Jakarta, Indonesia
- National Institute of Allergy and Infectious Disease, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Aaron Neal
- Indonesia Research Partnership on Infectious Diseases (INA-RESPOND), Central Jakarta, Indonesia
- National Institute of Allergy and Infectious Disease, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Herman Kosasih
- Indonesia Research Partnership on Infectious Diseases (INA-RESPOND), Central Jakarta, Indonesia
| | - Muhammad Karyana
- Indonesia Research Partnership on Infectious Diseases (INA-RESPOND), Central Jakarta, Indonesia
- Health Policy Agency, Ministry of Heath, Central Jakarta, Indonesia
| | - Chuen-Yen Lau
- Indonesia Research Partnership on Infectious Diseases (INA-RESPOND), Central Jakarta, Indonesia
- National Institute of Allergy and Infectious Disease, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Bachti Alisjahbana
- Indonesia Research Partnership on Infectious Diseases (INA-RESPOND), Central Jakarta, Indonesia
- Research Center for Care and Control of Infectious Disease, Universitas Padjadjaran, Bandung, Indonesia
- Department of Internal Medicine, Faculty of Medicine, Universitas Padjadjaran/Dr. Hasan Sadikin Hospital, Bandung, Indonesia
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Saha T, Arisoyin AE, Bollu B, Ashok T, Babu A, Issani A, Jhaveri S, Avanthika C. Enteric Fever: Diagnostic Challenges and the Importance of Early Intervention. Cureus 2023; 15:e41831. [PMID: 37575696 PMCID: PMC10423039 DOI: 10.7759/cureus.41831] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/12/2023] [Indexed: 08/15/2023] Open
Abstract
Enteric fever is a systemic infection caused by highly virulent Salmonella enterica serovars: Typhi and Paratyphi. Diagnosis of enteric fever is challenging due to a wide variety of clinical features which overlap with other febrile illnesses. The current diagnostic methods are limited because of the suboptimal sensitivity of conventional tests like blood culture in detecting organisms and the invasive nature of bone marrow culture. It emphasizes the need to develop improved and more reliable diagnostic modalities. The rising rates of multidrug-resistant Salmonella strains call for an accurate understanding of the current management of the disease. Proper public health measures and large-scale immunization programs will help reduce the burden of the disease. A comprehensive surveillance system can help detect the chronic carrier state and is crucial in understanding antibiotic susceptibility patterns. We conducted an all-language literature search on Medline, Cochrane, Embase, and Google Scholar till May 2022. The following search words and medical subject headings (MeSH) were used: "enteric fever," "Salmonella Typhi," "multidrug-resistant Salmonella," chronic carrier state," "Salmonella detection, "and "typhoid vaccine." We reviewed the literature on clinical features, pathophysiology, new diagnostic tests, and interventions to prevent the disease. This article explores enteric fever and its various clinical features and addresses the emerging threat of multidrug resistance. It focuses on novel methods for diagnosis and prevention strategies, including vaccines and the use of surveillance systems employed across different parts of the world.
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Affiliation(s)
- Tias Saha
- Internal Medicine, Samorita General Hospital, Faridpur, BGD
- Internal Medicine, Diabetic Association Medical College, Faridpur, BGD
| | | | - Bhaswanth Bollu
- Emergency Medicine, All India Institute of Medical Sciences, New Delhi, IND
| | - Tejaswini Ashok
- Internal Medicine, Jagadguru Sri Shivarathreeshwara Medical College, Mysore, IND
| | - Athira Babu
- Pediatrics, Saudi German Hospital, Dubai, ARE
| | - Ali Issani
- Emergency Medicine, Aga Khan University, Karachi, PAK
| | - Sharan Jhaveri
- Internal Medicine, Nathiba Hargovandas Lakhmichand Municipal Medical College, Ahmedabad, IND
| | - Chaithanya Avanthika
- Pediatrics, Icahn School of Medicine at Mount Sinai, Elmhurst Hospital Center, New York, USA
- Medicine and Surgery, Karnataka Institute of Medical Sciences, Hubli, IND
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Ferdousi T, Dutta AK, Chowdhury MAH, Islam K, Islam MT, Islam MZ, Bulbul MRH, Khan AI, Qadri F. Role of TaqMan array card in determining causative organisms of acute febrile illness in hospitalized patients. J Clin Lab Anal 2023; 37:e24948. [PMID: 37496432 PMCID: PMC10492456 DOI: 10.1002/jcla.24948] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Revised: 05/23/2023] [Accepted: 07/17/2023] [Indexed: 07/28/2023] Open
Abstract
BACKGROUND Acute febrile illness (AFI) is a prevalent disease in developing countries that is difficult to diagnose due to the diversity of infectious organisms and the poor quality of clinical diagnosis. TaqMan array card (TAC) can detect up to 35 AFI-associated organisms in 1.5 h, addressing diagnostic demands. In this study, we aimed to evaluate the role of TAC in determining the causative organisms in hospitalized AFI patients. METHODS The study had a cross-sectional design and enrolled 120 admitted patients with persistent fever for three or more days from the medicine ward of Chittagong Medical College Hospital (CMCH) and Bangladesh Institute of Tropical and Infectious Diseases Hospital (BITID). Blood samples were collected and then subjected to automated BacT/Alert blood culture, microbial culture, TAC assay, and typhoid/paratyphoid test. RESULTS The total number of study participants was 120, among them 48 (40%) samples showed a positive result in TAC card, 29 (24.16%) were TP positive and nine (7.51%) were culture positive. The number of organisms detected by the TAC card was 13 bacteria, three viruses, one protozoan, and one fungus. The sensitivity and specificity of the TAC assay for different bacterial pathogen compared to blood culture was 44.44%, and 90.99%, respectively. In contrast, the TP test had a sensitivity and specificity of 100% and 80%, respectively, compared to the blood culture test. CONCLUSION TAC can be a handful tool for detecting multiple organisms in AFI with high specificity which can facilitate early diagnosis of different pathogens contributing to AFI.
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Affiliation(s)
- Tabassum Ferdousi
- Bangladesh Institute of Tropical and Infectious DiseasesChattogramBangladesh
| | | | | | - Kamrul Islam
- International Centre for Diarrheal Disease Research, Bangladesh (icddr,b)DhakaBangladesh
| | - Md. Taufiqul Islam
- International Centre for Diarrheal Disease Research, Bangladesh (icddr,b)DhakaBangladesh
| | - Md. Zahirul Islam
- Institute for Developing Science and Health Initiatives (ideSHi)DhakaBangladesh
| | | | - Ashraful Islam Khan
- International Centre for Diarrheal Disease Research, Bangladesh (icddr,b)DhakaBangladesh
| | - Firdausi Qadri
- International Centre for Diarrheal Disease Research, Bangladesh (icddr,b)DhakaBangladesh
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Igiri BE, Okoduwa SIR, Munirat SA, Otu-Bassey IB, Bashir A, Onyiyioza OM, Enang IA, Okoduwa UJ. Diversity in Enteric Fever Diagnostic Protocols and Recommendation for Composite Reference Standard. IRANIAN JOURNAL OF MEDICAL MICROBIOLOGY 2023; 17:22-38. [DOI: 10.30699/ijmm.17.1.22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/02/2023]
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Nelwan EJ, Paramita LPL, Sinto R, Subekti D, Hosea FN, Nugroho P, Pohan HT. Validation of the Nelwan Score as a screening tool for the diagnosis of typhoid fever in adults in Indonesia. PLoS One 2023; 18:e0256508. [PMID: 37172043 PMCID: PMC10180627 DOI: 10.1371/journal.pone.0256508] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2021] [Accepted: 04/27/2023] [Indexed: 05/14/2023] Open
Abstract
INTRODUCTION Typhoid fever diagnosis is challenging for clinicians in areas with limited laboratory facilities. Scoring methods based on signs and symptoms are useful for screening for probable cases of typhoid fever. The Nelwan Score variables are derived from the clinical signs and symptoms of patients with suspected typhoid. We validated the Nelwan Score compared to laboratory tests as the gold standard. METHODS This cross-sectional study was conducted between July 2017 and January 2018 in five hospitals and two primary health care centers in Jakarta and Tangerang, Indonesia. Patients with fever for 3-14 days and gastrointestinal symptoms were evaluated using the Nelwan Score. Blood cultures, samples for polymerase chain reaction testing, and additional rectal swab cultures were collected simultaneously to confirm the diagnosis of typhoid. Data were analyzed using a contingency table to measure sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV), and the optimal cut-off of the Nelwan Score for typhoid diagnosis was determined using a receiver-operating characteristic curve. RESULT Typhoid was confirmed in 11 of the 233 patients (4.7%) with suspected typhoid. Among laboratory-confirmed typhoid cases, the median Nelwan Score was 11 (range: 9-13) and the optimal cut-off value was 10, with an area under the curve of 71.3%, sensitivity of 81.8%, specificity of 60.8%, PPV of 9.3%, and NPV of 98.5%. CONCLUSION A Nelwan Score of 10 is the best cut-off value for screening for typhoid fever. It is useful as screening tool for typhoid fever, where laboratory resources are limited, and could help to decrease irrational antibiotic use.
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Affiliation(s)
- Erni Juwita Nelwan
- Division of Tropical and Infectious Disease, Department of Internal Medicine, Cipto Mangunkusumo Hospital, Jakarta, Indonesia
- Faculty of Medicine Universitas Indonesia, Jakarta, Indonesia
| | - Luh Putu Listya Paramita
- Department of Internal Medicine, Cipto Mangunkusumo Hospital, Universitas Indonesia, Jakarta, Indonesia
| | - Robert Sinto
- Division of Tropical and Infectious Disease, Department of Internal Medicine, Cipto Mangunkusumo Hospital, Jakarta, Indonesia
| | - Decy Subekti
- Oxford University Clinical Research Unit, Faculty of Medicine Universitas Indonesia, Jakarta, Indonesia
| | | | - Pringgodigdo Nugroho
- Division of Nephrology and Hypertension, Department of Internal Medicine, Cipto Mangunkusumo Hospital, Jakarta, Indonesia
| | - Herdiman T Pohan
- Division of Tropical and Infectious Disease, Department of Internal Medicine, Cipto Mangunkusumo Hospital, Jakarta, Indonesia
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Comparative Analysis of Commercially Available Typhoid Point-of-Care Tests: Results of a Prospective and Hybrid Retrospective Multicenter Diagnostic Accuracy Study in Kenya and Pakistan. J Clin Microbiol 2022; 60:e0100022. [PMID: 36448816 PMCID: PMC9769786 DOI: 10.1128/jcm.01000-22] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
Blood and bone marrow cultures are considered the gold standard for the diagnosis of typhoid, but these methods require infrastructure and skilled staff that are not always available in low- and middle-income countries where typhoid is endemic. The objective of the study is to evaluate the sensitivity and specificity of nine commercially available Salmonella Typhi rapid diagnostic tests (RDTs) using blood culture as a reference standard in a multicenter study. This was a prospective and retrospective multicenter diagnostic accuracy study conducted in two geographically distant areas where typhoid is endemic (Pakistan and Kenya; NCT04801602). Nine RDTs were evaluated, including the Widal test. Point estimates for sensitivity and specificity were calculated using the Wilson method. Latent class analyses were performed using R to address the imperfect gold standard. A total of 531 serum samples were evaluated (264 blood culture positive; 267 blood culture negative). The sensitivity of RDTs varied widely (range, 0 to 78.8%), with the best overall performance shown by Enterocheck WB (72.7% sensitivity, 86.5% specificity). In latent class modeling, CTK IgG was found to have the highest sensitivity (79.1%), while the highest overall accuracy was observed with Enterocheck (73.8% sensitivity, 94.5% specificity). All commercially available Salmonella Typhi RDTs evaluated in the study had sensitivity and specificity values that fell below the required levels to be recommended for an accurate diagnosis. There were minimal differences in RDT performances between regions of endemicity. These findings highlight the clear need for new and more-accurate Salmonella Typhi tests.
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Kuehn R, Stoesser N, Eyre D, Darton TC, Basnyat B, Parry CM. Treatment of enteric fever (typhoid and paratyphoid fever) with cephalosporins. Cochrane Database Syst Rev 2022; 11:CD010452. [PMID: 36420914 PMCID: PMC9686137 DOI: 10.1002/14651858.cd010452.pub2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND Typhoid and paratyphoid (enteric fever) are febrile bacterial illnesses common in many low- and middle-income countries. The World Health Organization (WHO) currently recommends treatment with azithromycin, ciprofloxacin, or ceftriaxone due to widespread resistance to older, first-line antimicrobials. Resistance patterns vary in different locations and are changing over time. Fluoroquinolone resistance in South Asia often precludes the use of ciprofloxacin. Extensively drug-resistant strains of enteric fever have emerged in Pakistan. In some areas of the world, susceptibility to old first-line antimicrobials, such as chloramphenicol, has re-appeared. A Cochrane Review of the use of fluoroquinolones and azithromycin in the treatment of enteric fever has previously been undertaken, but the use of cephalosporins has not been systematically investigated and the optimal choice of drug and duration of treatment are uncertain. OBJECTIVES To evaluate the effectiveness of cephalosporins for treating enteric fever in children and adults compared to other antimicrobials. SEARCH METHODS We searched the Cochrane Infectious Diseases Group Specialized Register, CENTRAL, MEDLINE, Embase, LILACS, the WHO ICTRP and ClinicalTrials.gov up to 24 November 2021. We also searched reference lists of included trials, contacted researchers working in the field, and contacted relevant organizations. SELECTION CRITERIA We included randomized controlled trials (RCTs) in adults and children with enteric fever that compared a cephalosporin to another antimicrobial, a different cephalosporin, or a different treatment duration of the intervention cephalosporin. Enteric fever was diagnosed on the basis of blood culture, bone marrow culture, or molecular tests. DATA COLLECTION AND ANALYSIS We used standard Cochrane methods. Our primary outcomes were clinical failure, microbiological failure and relapse. Our secondary outcomes were time to defervescence, duration of hospital admission, convalescent faecal carriage, and adverse effects. We used the GRADE approach to assess certainty of evidence for each outcome. MAIN RESULTS We included 27 RCTs with 2231 total participants published between 1986 and 2016 across Africa, Asia, Europe, the Middle East and the Caribbean, with comparisons between cephalosporins and other antimicrobials used for the treatment of enteric fever in children and adults. The main comparisons are between antimicrobials in most common clinical use, namely cephalosporins compared to a fluoroquinolone and cephalosporins compared to azithromycin. Cephalosporin (cefixime) versus fluoroquinolones Clinical failure, microbiological failure and relapse may be increased in patients treated with cefixime compared to fluoroquinolones in three small trials published over 14 years ago: clinical failure (risk ratio (RR) 13.39, 95% confidence interval (CI) 3.24 to 55.39; 2 trials, 240 participants; low-certainty evidence); microbiological failure (RR 4.07, 95% CI 0.46 to 36.41; 2 trials, 240 participants; low-certainty evidence); relapse (RR 4.45, 95% CI 1.11 to 17.84; 2 trials, 220 participants; low-certainty evidence). Time to defervescence in participants treated with cefixime may be longer compared to participants treated with fluoroquinolones (mean difference (MD) 1.74 days, 95% CI 0.50 to 2.98, 3 trials, 425 participants; low-certainty evidence). Cephalosporin (ceftriaxone) versus azithromycin Ceftriaxone may result in a decrease in clinical failure compared to azithromycin, and it is unclear whether ceftriaxone has an effect on microbiological failure compared to azithromycin in two small trials published over 18 years ago and in one more recent trial, all conducted in participants under 18 years of age: clinical failure (RR 0.42, 95% CI 0.11 to 1.57; 3 trials, 196 participants; low-certainty evidence); microbiological failure (RR 1.95, 95% CI 0.36 to 10.64, 3 trials, 196 participants; very low-certainty evidence). It is unclear whether ceftriaxone increases or decreases relapse compared to azithromycin (RR 10.05, 95% CI 1.93 to 52.38; 3 trials, 185 participants; very low-certainty evidence). Time to defervescence in participants treated with ceftriaxone may be shorter compared to participants treated with azithromycin (mean difference of -0.52 days, 95% CI -0.91 to -0.12; 3 trials, 196 participants; low-certainty evidence). Cephalosporin (ceftriaxone) versus fluoroquinolones It is unclear whether ceftriaxone has an effect on clinical failure, microbiological failure, relapse, and time to defervescence compared to fluoroquinolones in three trials published over 28 years ago and two more recent trials: clinical failure (RR 3.77, 95% CI 0.72 to 19.81; 4 trials, 359 participants; very low-certainty evidence); microbiological failure (RR 1.65, 95% CI 0.40 to 6.83; 3 trials, 316 participants; very low-certainty evidence); relapse (RR 0.95, 95% CI 0.31 to 2.92; 3 trials, 297 participants; very low-certainty evidence) and time to defervescence (MD 2.73 days, 95% CI -0.37 to 5.84; 3 trials, 285 participants; very low-certainty evidence). It is unclear whether ceftriaxone decreases convalescent faecal carriage compared to the fluoroquinolone gatifloxacin (RR 0.18, 95% CI 0.01 to 3.72; 1 trial, 73 participants; very low-certainty evidence) and length of hospital stay may be longer in participants treated with ceftriaxone compared to participants treated with the fluoroquinolone ofloxacin (mean of 12 days (range 7 to 23 days) in the ceftriaxone group compared to a mean of 9 days (range 6 to 13 days) in the ofloxacin group; 1 trial, 47 participants; low-certainty evidence). AUTHORS' CONCLUSIONS Based on very low- to low-certainty evidence, ceftriaxone is an effective treatment for adults and children with enteric fever, with few adverse effects. Trials suggest that there may be no difference in the performance of ceftriaxone compared with azithromycin, fluoroquinolones, or chloramphenicol. Cefixime can also be used for treatment of enteric fever but may not perform as well as fluoroquinolones. We are unable to draw firm general conclusions on comparative contemporary effectiveness given that most trials were small and conducted over 20 years previously. Clinicians need to take into account current, local resistance patterns in addition to route of administration when choosing an antimicrobial.
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Affiliation(s)
- Rebecca Kuehn
- Department of Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, UK
| | - Nicole Stoesser
- Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - David Eyre
- Big Data Institute, Nuffield Department of Population Health, University of Oxford, Oxford, UK
| | - Thomas C Darton
- Department of Infection, Immunity and Cardiovascular Disease, The University of Sheffield, Sheffield, UK
| | - Buddha Basnyat
- Nuffield Department of Medicine, University of Oxford, Oxford, UK
- Oxford Clinical Research Unit/Patan Academy of Health Science, Nepal International Clinic, Kathmandu, Nepal
| | - Christopher Martin Parry
- Department of Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, UK
- Nuffield Department of Medicine, University of Oxford, Oxford, UK
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Khalid A, Ur Rehman A, Baig A, Ahsan W, Assir MZK. Concurrent Typhoid Fever and Dengue Hemorrhagic Fever: A Case Report. Cureus 2022; 14:e28600. [PMID: 36185892 PMCID: PMC9521295 DOI: 10.7759/cureus.28600] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/29/2022] [Indexed: 11/25/2022] Open
Abstract
Dengue virus can co-infect with a number of viruses, bacteria, and parasites of which dengue malaria co-infection is most well-known. We report a rare case of dengue virus co-infection with typhoid fever and the development of dengue hemorrhagic fever (DHF) during a dengue outbreak. The second spike of high-grade fever following initial defervescence with antibiotic therapy, hemorrhagic manifestations, new onset leucopenia and thrombocytopenia, and evidence of plasma leakage raised suspicion of DHF. Diagnosis of dengue co-infection was made by seroconversion for anti-dengue immunoglobulin M (IgM) antibodies by enzyme-linked immunosorbent assay (ELISA) on the seventh day of new-onset fever. Early recognition and judicious use of fluid therapy prevented the patient from developing shock and its complications. Prompt diagnosis, early recognition of plasma leakage, and appropriate management of DHF can reduce morbidity and mortality.
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10
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Ahmad Faris AN, Ahmad Najib M, Mohd Nazri MN, Hamzah ASA, Aziah I, Yusof NY, Mohamud R, Ismail I, Mustafa FH. Colorimetric Approach for Nucleic Acid Salmonella spp. Detection: A Systematic Review. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2022; 19:10570. [PMID: 36078284 PMCID: PMC9518084 DOI: 10.3390/ijerph191710570] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Revised: 08/09/2022] [Accepted: 08/17/2022] [Indexed: 06/15/2023]
Abstract
Water- and food-related health issues have received a lot of attention recently because food-poisoning bacteria, in particular, are becoming serious threats to human health. Currently, techniques used to detect these bacteria are time-consuming and laborious. To overcome these challenges, the colorimetric strategy is attractive because it provides simple, rapid and accurate sensing for the detection of Salmonella spp. bacteria. The aim of this study is to review the progress regarding the colorimetric method of nucleic acid for Salmonella detection. A literature search was conducted using three databases (PubMed, Scopus and ScienceDirect). Of the 88 studies identified in our search, 15 were included for further analysis. Salmonella bacteria from different species, such as S. Typhimurium, S. Enteritidis, S. Typhi and S. Paratyphi A, were identified using the colorimetric method. The limit of detection (LoD) was evaluated in two types of concentrations, which were colony-forming unit (CFU) and CFU per mL. The majority of the studies used spiked samples (53%) rather than real samples (33%) to determine the LoDs. More research is needed to assess the sensitivity and specificity of colorimetric nucleic acid in bacterial detection, as well as its potential use in routine diagnosis.
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Affiliation(s)
- Asma Nadia Ahmad Faris
- Institute for Research in Molecular Medicine (INFORMM), Health Campus, Universiti Sains Malaysia, Kubang Kerian 16150, Kelantan, Malaysia
| | - Mohamad Ahmad Najib
- Institute for Research in Molecular Medicine (INFORMM), Health Campus, Universiti Sains Malaysia, Kubang Kerian 16150, Kelantan, Malaysia
| | - Muhammad Najmi Mohd Nazri
- Institute for Research in Molecular Medicine (INFORMM), Health Campus, Universiti Sains Malaysia, Kubang Kerian 16150, Kelantan, Malaysia
| | - Amir Syahir Amir Hamzah
- Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, Serdang 43400, Selangor, Malaysia
| | - Ismail Aziah
- Institute for Research in Molecular Medicine (INFORMM), Health Campus, Universiti Sains Malaysia, Kubang Kerian 16150, Kelantan, Malaysia
| | - Nik Yusnoraini Yusof
- Institute for Research in Molecular Medicine (INFORMM), Health Campus, Universiti Sains Malaysia, Kubang Kerian 16150, Kelantan, Malaysia
| | - Rohimah Mohamud
- Department of Immunology, School of Medical Sciences, Universiti Sains Malaysia, Kubang Kerian 16150, Kelantan, Malaysia
| | - Irneza Ismail
- Advanced Devices & System (ADS) Research Group, Department of Electrical & Electronic Engineering, Faculty of Engineering and Built Environment, Universiti Sains Islam Malaysia, Bandar Baru Nilai, Nilai 71800, Negeri Sembilan, Malaysia
| | - Fatin Hamimi Mustafa
- Institute for Research in Molecular Medicine (INFORMM), Health Campus, Universiti Sains Malaysia, Kubang Kerian 16150, Kelantan, Malaysia
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11
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Kariuki F, Getanda P, Nyachieo A, Juma G, Kinyanjui P, Kamau J. Evaluation of the detection of staA, viaB and sopE genes in Salmonella spp. using the polymerase chain reaction (PCR). Arch Microbiol 2021; 204:25. [DOI: 10.1007/s00203-021-02654-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Revised: 10/07/2021] [Accepted: 10/08/2021] [Indexed: 11/24/2022]
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12
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Performance of Immunodiagnostic Tests for Typhoid Fever: A Systematic Review and Meta-Analysis. Pathogens 2021; 10:pathogens10091184. [PMID: 34578216 PMCID: PMC8467574 DOI: 10.3390/pathogens10091184] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Revised: 09/01/2021] [Accepted: 09/07/2021] [Indexed: 12/23/2022] Open
Abstract
Typhoid fever, also known as typhoid, is a life-threatening bacterial infection that remains a global health concern. The infection is associated with a significant morbidity and mortality rate, resulting in an urgent need for specific and rapid detection tests to aid prevention and management of the disease. The present review aims to assess the specificity and sensitivity of the available literature on the immunodiagnostics of typhoid fever. A literature search was conducted using three databases (PubMed, ProQuest and Scopus) and manual searches through the references of identified full texts to retrieve relevant literature published between 1 January 2011 and 31 December 2020. Of the 577 studies identified in our search, 12 were included in further analysis. Lipopolysaccharides (LPS) and hemolysin E (HlyE) were the most frequently studied antigens. The specimens examined in these studies included serum and saliva. Using blood culture as the gold standard, anti-LPS IgA gave the highest sensitivity of 96% (95% CI: 93–99) and specificity of 96% (95% CI: 93–99) for distinguishing between typhoid cases and healthy controls, whereas the combination of anti-LPS and anti-flagellin total IgGAM gave the highest sensitivity of 93% (95% CI: 86–99) and specificity of 95% (95% CI: 89–100) for distinguishing typhoid cases and other febrile infections. A comparably high sensitivity of 92% (95% CI: 86–98) and specificity of 89% (95% CI: 78–100) were shown in testing based on detection of the combination of anti-LPS (IgA and IgM) and anti-HlyE IgG as well as a slightly lower sensitivity of 91% (95% CI: 74–100) in the case of anti-50kDa IgA. Anti-50kDa IgM had the lowest sensitivity of 36% (95% CI: 6–65) against both healthy and febrile controls. The development of a rapid diagnostic test targeting antibodies against lipopolysaccharides combined with flagellin appeared to be a suitable approach for the rapid detection test of typhoid fever. Saliva is added benefit for rapid typhoid diagnosis since it is less invasive. As a result, further studies could be done to develop additional approaches for adopting such samples.
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13
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Manesh A, Meltzer E, Jin C, Britto C, Deodhar D, Radha S, Schwartz E, Rupali P. Typhoid and paratyphoid fever: a clinical seminar. J Travel Med 2021; 28:6129661. [PMID: 33550411 DOI: 10.1093/jtm/taab012] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/07/2020] [Revised: 01/07/2021] [Indexed: 01/06/2023]
Abstract
Rationale for review: Enteric fever (EF) caused by Salmonella enterica subspecies enterica serovar Typhi (Salmonella Typhi) and S. Paratyphi (Salmonella Paratyphi) remains an important cause of infectious morbidity and mortality in many low-income countries and, therefore, still poses a major infectious risk for travellers to endemic countries. Main findings: Although the global burden of EF has decreased over the past two decades, prevalence of EF remains high in Asia and Africa, with the highest prevalence reported from the Indian subcontinent. These statistics are mirrored by data on travel-related EF. Widespread and increasing antimicrobial resistance has narrowed treatment options for travel-related EF. Ceftriaxone- and azithromycin-based therapies are commonly used, even with the emergence of extremely drug-resistant typhoid in Pakistan. Preventive measures among locals and travellers include provision of safe food and water and vaccination. Food and water precautions offer limited protection, and the efficacy of Salmonella Typhi vaccines is only moderate signifying the need for travellers to be extra cautious. Recommendations: Improvement in the diagnosis of typhoid with high degree of clinical suspicion, better diagnostic assays, early and accurate detection of resistance, therapy with appropriate drugs, improvements in hygiene and sanitation with provision of safe drinking water in endemic areas and vaccination among travellers as well as in the endemic population are keys to controlling typhoid. While typhoid vaccines are recommended for travellers to high-risk areas, moderate efficacy and inability to protect against Salmonella Paratyphi are limitations to bear in mind. Improved Salmonella Typhi vaccines and vaccines against Salmonella Paratyphi A are required.
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Affiliation(s)
- Abi Manesh
- Department of Infectious Diseases, Christian Medical College, Vellore, India
| | - Eyal Meltzer
- Department of Medicine `C', Center for Geographic Medicine, Sheba Medical Center, Tel-Hashomer, Israel.,Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Celina Jin
- Oxford Vaccine Group, Department of Pediatrics, NIHR Oxford Biomedical Research Centre, University of Oxford, Oxford, UK
| | - Carl Britto
- Oxford Vaccine Group, Department of Pediatrics, NIHR Oxford Biomedical Research Centre, University of Oxford, Oxford, UK
| | - Divya Deodhar
- Department of Infectious Diseases, Christian Medical College, Vellore, India
| | - Sneha Radha
- Department of Infectious Diseases, Christian Medical College, Vellore, India
| | - Eli Schwartz
- Department of Medicine `C', Center for Geographic Medicine, Sheba Medical Center, Tel-Hashomer, Israel.,Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Priscilla Rupali
- Department of Infectious Diseases, Christian Medical College, Vellore, India
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14
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Enteric Fever Diagnosis: Current Challenges and Future Directions. Pathogens 2021; 10:pathogens10040410. [PMID: 33915749 PMCID: PMC8065732 DOI: 10.3390/pathogens10040410] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Revised: 03/23/2021] [Accepted: 03/27/2021] [Indexed: 12/21/2022] Open
Abstract
Enteric fever is a life-threatening systemic febrile disease caused by Salmonella enterica serovars Typhi and Paratyphi (S. Typhi and S. Paratyphi). Unfortunately, the burden of the disease remains high primarily due to the global spread of various drug-resistant Salmonella strains despite continuous advancement in the field. An accurate diagnosis is critical for effective control of the disease. However, enteric fever diagnosis based on clinical presentations is challenging due to overlapping symptoms with other febrile illnesses that are also prevalent in endemic areas. Current laboratory tests display suboptimal sensitivity and specificity, and no diagnostic methods are available for identifying asymptomatic carriers. Several research programs have employed systemic approaches to identify more specific biomarkers for early detection and asymptomatic carrier detection. This review discusses the pros and cons of currently available diagnostic tests for enteric fever, the advancement of research toward improved diagnostic tests, and the challenges of discovering new ideal biomarkers and tests.
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15
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Amalfitano E, Karlikow M, Norouzi M, Jaenes K, Cicek S, Masum F, Sadat Mousavi P, Guo Y, Tang L, Sydor A, Ma D, Pearson JD, Trcka D, Pinette M, Ambagala A, Babiuk S, Pickering B, Wrana J, Bremner R, Mazzulli T, Sinton D, Brumell JH, Green AA, Pardee K. A glucose meter interface for point-of-care gene circuit-based diagnostics. Nat Commun 2021; 12:724. [PMID: 33526784 PMCID: PMC7851131 DOI: 10.1038/s41467-020-20639-6] [Citation(s) in RCA: 51] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Accepted: 12/01/2020] [Indexed: 01/24/2023] Open
Abstract
Recent advances in cell-free synthetic biology have given rise to gene circuit-based sensors with the potential to provide decentralized and low-cost molecular diagnostics. However, it remains a challenge to deliver this sensing capacity into the hands of users in a practical manner. Here, we leverage the glucose meter, one of the most widely available point-of-care sensing devices, to serve as a universal reader for these decentralized diagnostics. We describe a molecular translator that can convert the activation of conventional gene circuit-based sensors into a glucose output that can be read by off-the-shelf glucose meters. We show the development of new glucogenic reporter systems, multiplexed reporter outputs and detection of nucleic acid targets down to the low attomolar range. Using this glucose-meter interface, we demonstrate the detection of a small-molecule analyte; sample-to-result diagnostics for typhoid, paratyphoid A/B; and show the potential for pandemic response with nucleic acid sensors for SARS-CoV-2. Getting synthetic biology circuit-based sensors into field applications is still a challenge. Here the authors combine a circuit sensor with a glucose meter for small analyte and nucleic acid detection.
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Affiliation(s)
- Evan Amalfitano
- Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, ON, M5S 3M2, Canada
| | - Margot Karlikow
- Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, ON, M5S 3M2, Canada
| | - Masoud Norouzi
- Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, ON, M5S 3M2, Canada
| | - Katariina Jaenes
- Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, ON, M5S 3M2, Canada
| | - Seray Cicek
- Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, ON, M5S 3M2, Canada
| | - Fahim Masum
- Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, ON, M5S 3M2, Canada
| | | | - Yuxiu Guo
- Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, ON, M5S 3M2, Canada
| | - Laura Tang
- Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, ON, M5S 3M2, Canada
| | - Andrew Sydor
- Program in Cell Biology, Hospital for Sick Children, Peter Gilgan Center for Research and Learning, Toronto, ON, M5G 0A4, Canada
| | - Duo Ma
- Biodesign Center for Molecular Design and Biomimetics, The Biodesign Institute and the School of Molecular Sciences, Arizona State University, AZ, 85287, USA
| | - Joel D Pearson
- Lunenfeld Tanenbaum Research Institute, Mt Sinai Hospital, Sinai Health System, Toronto, M5G 1X5, ON, Canada.,Department of Ophthalmology and Vision Science, University of Toronto, Toronto, M5T 3A9, ON, Canada.,Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, M5S 1A8, ON, Canada
| | - Daniel Trcka
- Lunenfeld Tanenbaum Research Institute, Mt Sinai Hospital, Sinai Health System, Toronto, M5G 1X5, ON, Canada
| | - Mathieu Pinette
- Canadian Food Inspection Agency, National Centre for Foreign Animal Disease, Winnipeg, R3E 3M4, MB, Canada
| | - Aruna Ambagala
- Canadian Food Inspection Agency, National Centre for Foreign Animal Disease, Winnipeg, R3E 3M4, MB, Canada
| | - Shawn Babiuk
- Canadian Food Inspection Agency, National Centre for Foreign Animal Disease, Winnipeg, R3E 3M4, MB, Canada
| | - Bradley Pickering
- Canadian Food Inspection Agency, National Centre for Foreign Animal Disease, Winnipeg, R3E 3M4, MB, Canada.,Department of Medical Microbiology and Infectious Diseases, Faculty of Medicine, University of Manitoba, Winnipeg, R3E 0J9, MB, Canada.,Iowa State University, College of Veterinary Medicine, Department of Veterinary Microbiology and Preventive Medicine, Ames, IA, 50011, USA
| | - Jeff Wrana
- Lunenfeld Tanenbaum Research Institute, Mt Sinai Hospital, Sinai Health System, Toronto, M5G 1X5, ON, Canada.,Department of Molecular Genetics, University of Toronto, Toronto, M5S 1A8, ON, Canada
| | - Rod Bremner
- Lunenfeld Tanenbaum Research Institute, Mt Sinai Hospital, Sinai Health System, Toronto, M5G 1X5, ON, Canada.,Department of Ophthalmology and Vision Science, University of Toronto, Toronto, M5T 3A9, ON, Canada.,Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, M5S 1A8, ON, Canada
| | - Tony Mazzulli
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, M5S 1A8, ON, Canada.,Department of Microbiology, Sinai Health System/University Health Network, Toronto, M5G 1X5, ON, Canada
| | - David Sinton
- Department of Mechanical and Industrial Engineering, University of Toronto, Toronto, M5S 3G8, ON, Canada
| | - John H Brumell
- Program in Cell Biology, Hospital for Sick Children, Peter Gilgan Center for Research and Learning, Toronto, ON, M5G 0A4, Canada.,Department of Molecular Genetics, University of Toronto, Toronto, M5S 1A8, ON, Canada.,Institute of Medical Science, University of Toronto, Toronto, M5S 1A8, ON, Canada.,SickKids IBD Centre, Hospital for Sick Children, Toronto, M5G 1X8, ON, Canada
| | - Alexander A Green
- Biodesign Center for Molecular Design and Biomimetics, The Biodesign Institute and the School of Molecular Sciences, Arizona State University, AZ, 85287, USA.,Department of Biomedical Engineering, Boston University, Boston, MA, 02215, USA
| | - Keith Pardee
- Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, ON, M5S 3M2, Canada. .,Department of Mechanical and Industrial Engineering, University of Toronto, Toronto, M5S 3G8, ON, Canada.
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16
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Wolking D, Karmacharya D, Bista M, Shrestha R, Pandit P, Sharma A, Manandhar S, Shrestha B, Bajracharya S, Bhatta T, Dulal S, Rajbhandari R, Smith B, Mazet J, Goldstein T, Johnson C. Vulnerabilities for Exposure to Emerging Infectious Disease at Urban Settlements in Nepal. ECOHEALTH 2020; 17:345-358. [PMID: 33206274 PMCID: PMC7672689 DOI: 10.1007/s10393-020-01499-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/23/2019] [Revised: 07/01/2020] [Accepted: 10/02/2020] [Indexed: 06/11/2023]
Abstract
In Nepal, rapid urbanization and rural-to-urban migration especially due to internal civil conflict have catalyzed the development of temporary settlements, often along rivers on undeveloped land. This study conducted surveillance for viruses in small mammals and assessed potential risks for virus transmission to people in urban settlements along rivers in Kathmandu, Nepal. We collected samples from 411 small mammals (100 rodents and 311 shrews) at four riverside settlement sites and detected six viruses from four virus families including Thottapalayam virus; a strain of murine coronavirus; two new paramyxoviruses; and two new rhabdoviruses. Additionally, we conducted surveys of 264 residents to characterize animal-human contact. Forty-eight percent of individuals reported contact with wildlife, primarily with rodents and shrews (91%). Our findings confirm that rodents and shrews should be considered a health threat for residents of temporary settlements, and that assessment of disease transmission risk coupled with targeted surveillance for emerging pathogens could lead to improved disease control and health security for urban populations. Additionally, interventions focused on disease prevention should consider the unique urban ecology and social dynamics in temporary settlements, along with the importance of community engagement for identifying solutions that address specific multi-dimensional challenges that life on the urban river margins presents.
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Affiliation(s)
- David Wolking
- One Health Institute, University of California, Davis, USA
| | - Dibesh Karmacharya
- Center for Molecular Dynamics Nepal (CMDN), Thapathali -11, Kathmandu, Nepal.
| | - Manisha Bista
- Center for Molecular Dynamics Nepal (CMDN), Thapathali -11, Kathmandu, Nepal
| | - Rima Shrestha
- One Health Institute, University of California, Davis, USA
| | - Pranav Pandit
- One Health Institute, University of California, Davis, USA
| | - Ajay Sharma
- Center for Molecular Dynamics Nepal (CMDN), Thapathali -11, Kathmandu, Nepal
| | - Sulochana Manandhar
- Center for Molecular Dynamics Nepal (CMDN), Thapathali -11, Kathmandu, Nepal
| | - Bishwo Shrestha
- Center for Molecular Dynamics Nepal (CMDN), Thapathali -11, Kathmandu, Nepal
| | | | - Tarka Bhatta
- Center for Molecular Dynamics Nepal (CMDN), Thapathali -11, Kathmandu, Nepal
| | - Santosh Dulal
- Center for Molecular Dynamics Nepal (CMDN), Thapathali -11, Kathmandu, Nepal
| | - Rajesh Rajbhandari
- Center for Molecular Dynamics Nepal (CMDN), Thapathali -11, Kathmandu, Nepal
| | - Brett Smith
- One Health Institute, University of California, Davis, USA
| | - Jonna Mazet
- One Health Institute, University of California, Davis, USA
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17
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Alhaj-Qasem DM, Al-Hatamleh MAI, Irekeola AA, Khalid MF, Mohamud R, Ismail A, Mustafa FH. Laboratory Diagnosis of Paratyphoid Fever: Opportunity of Surface Plasmon Resonance. Diagnostics (Basel) 2020; 10:diagnostics10070438. [PMID: 32605310 PMCID: PMC7400347 DOI: 10.3390/diagnostics10070438] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Revised: 06/18/2020] [Accepted: 06/25/2020] [Indexed: 12/19/2022] Open
Abstract
Paratyphoid fever is caused by the bacterium Salmonellaenterica serovar Paratyphi (A, B and C), and contributes significantly to global disease burden. One of the major challenges in the diagnosis of paratyphoid fever is the lack of a proper gold standard. Given the absence of a licensed vaccine against S. Paratyphi, this diagnostic gap leads to inappropriate antibiotics use, thus, enhancing antimicrobial resistance. In addition, the symptoms of paratyphoid overlap with other infections, including the closely related typhoid fever. Since the development and utilization of a standard, sensitive, and accurate diagnostic method is essential in controlling any disease, this review discusses a new promising approach to aid the diagnosis of paratyphoid fever. This advocated approach is based on the use of surface plasmon resonance (SPR) biosensor and DNA probes to detect specific nucleic acid sequences of S. Paratyphi. We believe that this SPR-based genoassay can be a potent alternative to the current conventional diagnostic methods, and could become a rapid diagnostic tool for paratyphoid fever.
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Affiliation(s)
| | - Mohammad A. I. Al-Hatamleh
- Department of Immunology, School of Medical Sciences, Universiti Sains Malaysia, Kubang Kerian, Kelantan 16150, Malaysia; (M.A.I.A.-H.); (R.M.)
| | - Ahmad Adebayo Irekeola
- Department of Medical Microbiology and Parasitology, School of Medical Sciences, Universiti Sains Malaysia, Kubang Kerian, Kelantan 16150, Malaysia;
- Microbiology Unit, Department of Biological Sciences, College of Natural and Applied Sciences, Summit University Offa, Offa PMB 4412, Kwara State, Nigeria
| | - Muhammad Fazli Khalid
- Institute for Research in Molecular Medicine (INFORMM), Universiti Sains Malaysia, Kubang Kerian, Kelantan 16150, Malaysia; (M.F.K.); (A.I.)
| | - Rohimah Mohamud
- Department of Immunology, School of Medical Sciences, Universiti Sains Malaysia, Kubang Kerian, Kelantan 16150, Malaysia; (M.A.I.A.-H.); (R.M.)
- Hospital Universiti Sains Malaysia, Kubang Kerian, Kelantan 16150, Malaysia
| | - Aziah Ismail
- Institute for Research in Molecular Medicine (INFORMM), Universiti Sains Malaysia, Kubang Kerian, Kelantan 16150, Malaysia; (M.F.K.); (A.I.)
| | - Fatin Hamimi Mustafa
- Institute for Research in Molecular Medicine (INFORMM), Universiti Sains Malaysia, Kubang Kerian, Kelantan 16150, Malaysia; (M.F.K.); (A.I.)
- Correspondence: ; Tel.: +60-9767-2432
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18
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Mather RG, Hopkins H, Parry CM, Dittrich S. Redefining typhoid diagnosis: what would an improved test need to look like? BMJ Glob Health 2019; 4:e001831. [PMID: 31749999 PMCID: PMC6830052 DOI: 10.1136/bmjgh-2019-001831] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2019] [Revised: 10/04/2019] [Accepted: 10/05/2019] [Indexed: 12/14/2022] Open
Abstract
INTRODUCTION Typhoid fever is one of the most common bacterial causes of acute febrile illness in the developing world, with an estimated 10.9 million new cases and 116.8 thousand deaths in 2017. Typhoid point-of-care (POC) diagnostic tests are widely used but have poor sensitivity and specificity, resulting in antibiotic overuse that has led to the emergence and spread of multidrug-resistant strains. With recent advances in typhoid surveillance and detection, this is the ideal time to produce a target product profile (TPP) that guides product development and ensure that a next-generation test meets the needs of users in the resource-limited settings where typhoid is endemic. METHODS A structured literature review was conducted to develop a draft TPP for a next-generation typhoid diagnostic test with minimal and optimal desired characteristics for 36 test parameters. The TPP was refined using feedback collected from a Delphi survey of key stakeholders in clinical medicine, microbiology, diagnostics and public and global health. RESULTS A next-generation typhoid diagnostic test should improve patient management through the diagnosis and treatment of infection with acute Salmonella enterica serovars Typhi or Paratyphi with a sensitivity ≥90% and specificity ≥95%. The test would ideally be used at the lowest level of the healthcare system in settings without a reliable power or water supply and provide results in <15 min at a cost of CONCLUSION This report outlines the first comprehensive TPP for typhoid fever and is intended to guide the development of a next-generation typhoid diagnostic test. An accurate POC test will reduce the morbidity and mortality of typhoid fever through rapid diagnosis and treatment and will have the greatest impact in reducing antimicrobial resistance if it is combined with diagnostics for other causes of acute febrile illness in a treatment algorithm.
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Affiliation(s)
- Richard G Mather
- Malaria and Fever Program, Foundation for Innovative New Diagnostics (FIND), Geneva, Switzerland
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, UK
| | - Heidi Hopkins
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, UK
| | - Christopher M Parry
- Department of Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, UK
- School of Tropical Medicine and Global Health, Nagasaki University, Nagasaki, Japan
| | - Sabine Dittrich
- Malaria and Fever Program, Foundation for Innovative New Diagnostics (FIND), Geneva, Switzerland
- Nuffield Department of Medicine, University of Oxford, Oxford, UK
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19
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Popoola O, Kehinde A, Ogunleye V, Adewusi OJ, Toy T, Mogeni OD, Aroyewun EO, Agbi S, Adekanmbi O, Adepoju A, Muyibi S, Adebiyi I, Elaturoti OO, Nwimo C, Adeoti H, Omotosho T, Akinlabi OC, Adegoke PA, Adeyanju OA, Panzner U, Baker S, Park SE, Marks F, Okeke IN. Bacteremia Among Febrile Patients Attending Selected Healthcare Facilities in Ibadan, Nigeria. Clin Infect Dis 2019; 69:S466-S473. [PMID: 31665773 PMCID: PMC6821210 DOI: 10.1093/cid/ciz516] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND The relative contribution of bacterial infections to febrile disease is poorly understood in many African countries due to diagnostic limitations. This study screened pediatric and adult patients attending 4 healthcare facilities in Ibadan, Nigeria, for bacteremia and malaria parasitemia. METHODS Febrile patients underwent clinical diagnosis, malaria parasite testing, and blood culture. Bacteria from positive blood cultures were isolated and speciated using biochemical and serological methods, and Salmonella subtyping was performed by polymerase chain reaction. Antimicrobial susceptibility was tested by disk diffusion. RESULTS A total of 682 patients were recruited between 16 June and 16 October 2017; 467 (68.5%) were <18 years of age. Bacterial pathogens were cultured from the blood of 117 (17.2%) patients, with Staphylococcus aureus (69 [59.0%]) and Salmonella enterica (34 [29.1%]) being the most common species recovered. Twenty-seven (79.4%) of the Salmonella isolates were serovar Typhi and the other 7 belonged to nontyphoidal Salmonella serovarieties. Thirty-four individuals were found to be coinfected with Plasmodium falciparum and bacteria. Five (14.7%) of these coinfections were with Salmonella, all in children aged <5 years. Antimicrobial susceptibility testing revealed that most of the Salmonella and Staphylococcus isolates were multidrug resistant. CONCLUSIONS The study demonstrates that bacteria were commonly recovered from febrile patients with or without malaria in this location. Focused and extended epidemiological studies are needed for the introduction of typhoid conjugate vaccines that have the potential to prevent a major cause of severe community-acquired febrile diseases in our locality.
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Affiliation(s)
- Oluwafemi Popoola
- Department of Community Medicine, Faculty of Public Health, College of Medicine, University of Ibadan, Nigeria
- University College Hospital Ibadan, Nigeria
| | - Aderemi Kehinde
- University College Hospital Ibadan, Nigeria
- Department of Medical Microbiology and Parasitology, and, Nigeria
| | | | | | - Trevor Toy
- International Vaccine Institute, Seoul National University Research Park, Republic of Korea
| | - Ondari D Mogeni
- International Vaccine Institute, Seoul National University Research Park, Republic of Korea
| | | | - Sarah Agbi
- College of Medicine, University of Ibadan, Nigeria
| | - Olukemi Adekanmbi
- University College Hospital Ibadan, Nigeria
- Department of Medicine, University of Ibadan
| | - Akinlolu Adepoju
- University College Hospital Ibadan, Nigeria
- Department of Paediatrics, College of Medicine, University of Ibadan
| | | | | | | | | | | | | | - Olabisi C Akinlabi
- Department of Pharmaceutical Microbiology, Faculty of Pharmacy, University of Ibadan
| | | | | | - Ursula Panzner
- International Vaccine Institute, Seoul National University Research Park, Republic of Korea
| | - Stephen Baker
- Department of Medicine, University of Cambridge, Cambridge, United Kingdom
| | - Se Eun Park
- International Vaccine Institute, Seoul National University Research Park, Republic of Korea
- Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
| | - Florian Marks
- International Vaccine Institute, Seoul National University Research Park, Republic of Korea
- Department of Medicine, University of Cambridge, Cambridge, United Kingdom
| | - Iruka N Okeke
- Department of Pharmaceutical Microbiology, Faculty of Pharmacy, University of Ibadan
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Msefula CL, Olgemoeller F, Jambo N, Segula D, Van Tan T, Nyirenda TS, Nedi W, Kennedy N, Graham M, Henrion MYR, Baker S, Feasey N, Gordon M, Heyderman RS. Ascertaining the burden of invasive Salmonella disease in hospitalised febrile children aged under four years in Blantyre, Malawi. PLoS Negl Trop Dis 2019; 13:e0007539. [PMID: 31314752 PMCID: PMC6663031 DOI: 10.1371/journal.pntd.0007539] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Revised: 07/29/2019] [Accepted: 06/10/2019] [Indexed: 11/19/2022] Open
Abstract
Typhoid fever is endemic across sub-Saharan Africa. However, estimates of the burden of typhoid are undermined by insufficient blood volumes and lack of sensitivity of blood culture. Here, we aimed to address this limitation by exploiting pre-enrichment culture followed by PCR, alongside routine blood culture to improve typhoid case detection. We carried out a prospective diagnostic cohort study and enrolled children (aged 0-4 years) with non-specific febrile disease admitted to a tertiary hospital in Blantyre, Malawi from August 2014 to July 2016. Blood was collected for culture (BC) and real-time PCR after a pre-enrichment culture in tryptone soy broth and ox-bile. DNA was subjected to PCR for invA (Pan-Salmonella), staG (S. Typhi), and fliC (S. Typhimurium) genes. A positive PCR was defined as invA plus either staG or fliC (CT<29). IgM and IgG ELISA against four S. Typhi antigens was also performed. In total, 643 children (median age 1.3 years) with nonspecific febrile disease were enrolled; 31 (4.8%) were BC positive for Salmonella (n = 13 S. Typhi, n = 16 S. Typhimurium, and n = 2 S. Enteritidis). Pre-enrichment culture of blood followed by PCR identified a further 8 S. Typhi and 15 S. Typhimurium positive children. IgM and IgG titres to the S. Typhi antigen STY1498 (haemolysin) were significantly higher in children that were PCR positive but blood culture negative compared to febrile children with all other non-typhoid illnesses. The addition of pre-enrichment culture and PCR increased the case ascertainment of invasive Salmonella disease in children by 62-94%. These data support recent burden estimates that highlight the insensitivity of blood cultures and support the targeting of pre-school children for typhoid vaccine prevention in Africa. Blood culture with real-time PCR following pre-enrichment should be used to further refine estimates of vaccine effectiveness in typhoid vaccine trials.
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Affiliation(s)
- Chisomo L. Msefula
- Pathology Department, College of Medicine, University of Malawi, Blantyre, Malawi
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, College of Medicine, University of Malawi, Blantyre, Malawi
- * E-mail:
| | - Franziska Olgemoeller
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, College of Medicine, University of Malawi, Blantyre, Malawi
- Department of Paediatrics, Queen Elizabeth Central Hospital, College of Medicine, University of Malawi, Blantyre, Malawi
| | - Ndaru Jambo
- Pathology Department, College of Medicine, University of Malawi, Blantyre, Malawi
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, College of Medicine, University of Malawi, Blantyre, Malawi
- University of Liverpool, Liverpool, United Kingdom
| | - Dalitso Segula
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, College of Medicine, University of Malawi, Blantyre, Malawi
- Department of Internal Medicine, Queen Elizabeth Central Hospital, College of Medicine, University of Malawi, Blantyre, Malawi
| | - Trinh Van Tan
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
| | - Tonney S. Nyirenda
- Pathology Department, College of Medicine, University of Malawi, Blantyre, Malawi
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, College of Medicine, University of Malawi, Blantyre, Malawi
| | - Wilfred Nedi
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, College of Medicine, University of Malawi, Blantyre, Malawi
| | - Neil Kennedy
- Department of Paediatrics, Queen Elizabeth Central Hospital, College of Medicine, University of Malawi, Blantyre, Malawi
- Centre for Medical Education, Queens University, Belfast, United Kingdom
| | - Matthew Graham
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
| | - Marc Y. R. Henrion
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, College of Medicine, University of Malawi, Blantyre, Malawi
- Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Stephen Baker
- The Department of Medicine, The University of Cambridge, Cambridge, United Kingdom
| | - Nicholas Feasey
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, College of Medicine, University of Malawi, Blantyre, Malawi
- Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Melita Gordon
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, College of Medicine, University of Malawi, Blantyre, Malawi
- University of Liverpool, Liverpool, United Kingdom
| | - Robert S. Heyderman
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, College of Medicine, University of Malawi, Blantyre, Malawi
- Division of Infection & Immunity, University College London, London, England, United Kingdom
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Arora P, Thorlund K, Brenner DR, Andrews JR. Comparative accuracy of typhoid diagnostic tools: A Bayesian latent-class network analysis. PLoS Negl Trop Dis 2019; 13:e0007303. [PMID: 31067228 PMCID: PMC6527309 DOI: 10.1371/journal.pntd.0007303] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Revised: 05/20/2019] [Accepted: 03/13/2019] [Indexed: 11/19/2022] Open
Abstract
Background Typhoid fevers are infections caused by the bacteria Salmonella enterica serovar Typhi (Salmonella Typhi) and Paratyphi A, B and C (Salmonella Paratyphi). Approximately 17.8 million incident cases of typhoid fever occur annually, and incidence is highest in children. The accuracy of current diagnostic tests of typhoid fever is poorly understood. We aimed to determine the comparative accuracy of available tests for the pediatric population. Methods We first conducted a systematic literature review to identify studies that compared diagnostic tests for typhoid fever in children (aged ≤15 years) to blood culture results. We applied a Bayesian latent-class extension to a network meta-analysis model. We modelled known diagnostic properties of bone marrow culture and the relationship between bone marrow and blood culture as informative priors in a Bayesian framework. We tested sensitivities for the proportion of negative blood samples that were false as well as bone marrow sensitivity and specificity. Results We found 510 comparisons from 196 studies and 57 specific to the pediatric population. IgM-based tests outperformed their IgG-based counterparts for ELISA and Typhidot tests. The lateral flow IgG test performed comparatively well with 92% sensitivity (72% to 98% across scenario analyses) and 94% specificity. The most sensitive test of those investigated for the South Asian pediatric population was the Reverse Passive Hemagglutination Assay with 99% sensitivity (98% - 100% across scenario analyses). Adding a Widal slide test to other typhoid diagnostics did not substantially improve diagnostic performance beyond the single test alone, however, a lateral flow-based IgG rapid test combined with the typhoid/paratyphoid (TPT) assay yielded improvements in sensitivity without substantial declines in specificity and was the best performing combination test in this setting. Conclusion In the pediatric population, lateral-flow IgG, TPT and Reverse Passive Hemagglutination tests had high diagnostic accuracy compared to other diagnostics. Combinations of tests may provide a feasible option to increase diagnostic sensitivity. South Asia has the most informed set of data on typhoid diagnostic testing accuracy, and the evidence base in other important regions needs to be expanded. Typhoid fever is an infection caused by the bacterium Salmonella Typhi. Typhoid fever is rare in developed countries but remains high in the developing world. Effective treatment is available but accurate diagnosis of typhoid fever is challenging as typhoid fever can be difficult to distinguish from other infections. Bone marrow culture is the most accurate diagnostic test for typhoid fever however is invasive and not feasible in many settings. New vaccines for typhoid and the need for improved estimates of burden increases the demand for improved understanding of diagnostic accuracy. Comparing the diagnostic accuracy of tests for typhoid fever is challenging as head-to-head studies are few. We applied newly developed methods for comparative evaluation of diagnostic tests for typhoid fever in children using statistical approaches that allowed for the proper incorporation of uncertainty and comparison of tests that had not been compared directly. The lateral-flow IgG, TPT and Reverse Passive Hemagglutination tests all had good diagnostic accuracy compared to other diagnostics. Combinations of tests may provide a feasible option to increase diagnostic sensitivity. Finally, while South Asia has the most informed set of data on typhoid diagnostic testing accuracy, the evidence base in other important regions needs to be expanded.
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Affiliation(s)
- Paul Arora
- Dalla Lana School of Public Health, Division of Epidemiology, University of Toronto, Ontario, Canada
- * E-mail:
| | - Kristian Thorlund
- Department of Health Research Methods, Evidence, and Impact, McMaster University, Hamilton, Ontario, Canada
| | - Darren R. Brenner
- Departments of Oncology and Community Health Sciences, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Jason R. Andrews
- Division of Infectious Diseases and Geographic Medicine, Stanford University, Stanford, California, United States of America
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Gal-Mor O. Persistent Infection and Long-Term Carriage of Typhoidal and Nontyphoidal Salmonellae. Clin Microbiol Rev 2019; 32:e00088-18. [PMID: 30487167 PMCID: PMC6302356 DOI: 10.1128/cmr.00088-18] [Citation(s) in RCA: 74] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The ability of pathogenic bacteria to affect higher organisms and cause disease is one of the most dramatic properties of microorganisms. Some pathogens can establish transient colonization only, but others are capable of infecting their host for many years or even for a lifetime. Long-term infection is called persistence, and this phenotype is fundamental for the biology of important human pathogens, including Helicobacter pylori, Mycobacterium tuberculosis, and Salmonella enterica Both typhoidal and nontyphoidal serovars of the species Salmonella enterica can cause persistent infection in humans; however, as these two Salmonella groups cause clinically distinct diseases, the characteristics of their persistent infections in humans differ significantly. Here, following a general summary of Salmonella pathogenicity, host specificity, epidemiology, and laboratory diagnosis, I review the current knowledge about Salmonella persistence and discuss the relevant epidemiology of persistence (including carrier rate, duration of shedding, and host and pathogen risk factors), the host response to Salmonella persistence, Salmonella genes involved in this lifestyle, as well as genetic and phenotypic changes acquired during prolonged infection within the host. Additionally, I highlight differences between the persistence of typhoidal and nontyphoidal Salmonella strains in humans and summarize the current gaps and limitations in our understanding, diagnosis, and curing of persistent Salmonella infections.
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Affiliation(s)
- Ohad Gal-Mor
- Infectious Diseases Research Laboratory, Sheba Medical Center, Tel-Hashomer, Israel
- Department of Clinical Microbiology and Immunology, Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv, Israel
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Ajibola O, Mshelia MB, Gulumbe BH, Eze AA. Typhoid Fever Diagnosis in Endemic Countries: A Clog in the Wheel of Progress? MEDICINA (KAUNAS, LITHUANIA) 2018; 54:E23. [PMID: 30344254 PMCID: PMC6037256 DOI: 10.3390/medicina54020023] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 03/07/2018] [Revised: 04/17/2018] [Accepted: 04/19/2018] [Indexed: 12/27/2022]
Abstract
Typhoid fever causes significant morbidity and mortality in developing countries, with inaccurate estimates in some countries affected, especially those situated in Sub-Saharan Africa. Disease burden assessment is limited by lack of a high degree of sensitivity and specificity by many current rapid diagnostic tests. Some of the new technologies, such as PCR and proteomics, may also be useful but are difficult for low-resource settings to apply as point-of-care diagnostics. Weak laboratory surveillance systems may also contribute to the spread of multidrug resistant Salmonella serovar Typhi across endemic areas. In addition, most typhoid-endemic countries employ serological tests that have low sensitivity and specificity making diagnosis unreliable. Here we review currently available typhoid fever diagnostics, and advances in serodiagnosis of S. Typhi.
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Affiliation(s)
- Olumide Ajibola
- Department of Microbiology, Faculty of Science, Federal University Birnin Kebbi, P.M.B. 1157 Kalgo, Kebbi State, Nigeria.
| | - Mari B Mshelia
- Department of Microbiology, Faculty of Science, Federal University Birnin Kebbi, P.M.B. 1157 Kalgo, Kebbi State, Nigeria.
| | - Bashar H Gulumbe
- Department of Microbiology, Faculty of Science, Federal University Birnin Kebbi, P.M.B. 1157 Kalgo, Kebbi State, Nigeria.
| | - Anthonius A Eze
- Department of Medical Biochemistry, University of Nigeria, Enugu Campus, Enugu 400241, Nigeria.
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24
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Anyanwu LJ, Mohammad A, Abdullahi L, Farinyaro A, Obaro S. Determinants of postoperative morbidity and mortality in children managed for typhoid intestinal perforation in Kano Nigeria. J Pediatr Surg 2018; 53:847-852. [PMID: 29277466 DOI: 10.1016/j.jpedsurg.2017.11.058] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/30/2017] [Revised: 11/18/2017] [Accepted: 11/26/2017] [Indexed: 11/28/2022]
Abstract
BACKGROUND Intestinal perforation is a serious but poorly understood complication of typhoid fever. This study aims to determine the patient factors associated with postoperative morbidity and mortality. METHODS We retrospectively reviewed the records of all children presenting to our unit with typhoid intestinal perforation (TIP) between March 2009 and December 2013. The patients were grouped based on postoperative outcome status and were compared with respect to patient related variables, using chi square test. Multivariate analysis was performed using a binary logistic regression model. Significance was assigned to a p-value <0.05. RESULTS The records of 129 children were analyzed. There were 78 (60.5%) boys and 51 (39.5%) girls. The male/female ratio was 1.53:1. Their ages ranged from 3years to 13years (mean 8.14years; SD 2.61years). A single intestinal perforation was seen in 73.4% (94/128) of them, while 26.6% (34/128) had two or more. Mortality rate was 10.9%. Multivariate analysis showed that multiple intestinal perforations significantly predicted postoperative mortality (p=0.005) and development of postoperative fecal fistula (p=0.013), while serum albumin <32g/L was a predictor of postoperative surgical site infection (p=0.002). CONCLUSION Multiple intestinal perforations, a postoperative fecal fistula and hypoalbuminemia adversely affected outcome in our patients. LEVEL OF EVIDENCE III (Retrospective study). Type of study-Prognosis study.
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Affiliation(s)
- Lofty-John Anyanwu
- Paediatric Surgery Unit, Department Of Surgery, Aminu Kano Teaching Hospital and Bayero University Kano, Nigeria.
| | - Aminu Mohammad
- Paediatric Surgery Unit, Department Of Surgery, Aminu Kano Teaching Hospital and Bayero University Kano, Nigeria
| | - Lawal Abdullahi
- Paediatric Surgery Unit, Department Of Surgery, Aminu Kano Teaching Hospital and Bayero University Kano, Nigeria
| | - Aliyu Farinyaro
- Paediatric Surgery Unit, Department Of Surgery, Aminu Kano Teaching Hospital and Bayero University Kano, Nigeria
| | - Stephen Obaro
- Division Of Pediatrics Infectious Disease University of Nebraska Medical Center, Omaha, USA
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25
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Kavai SM, Kangogo M, Muigai AWT, Kariuki S. Analysis of Trends in Resistance to Fluoroquinolones and Extended Spectrum Beta-Lactams among <i>Salmonella</i> Typhi Isolates Obtained from Patients at Four Outpatient Clinics in Nairobi County, Kenya. ACTA ACUST UNITED AC 2018. [DOI: 10.4236/aim.2018.87038] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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26
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Abstract
PURPOSE OF REVIEW Increasing antimicrobial resistance in Salmonella Typhi is a serious public health concern, especially in industrializing countries. Here we review recent clinical and laboratory data concerning the evolution of antimicrobial resistance, with particular reference to the emergence resistance against fluoroquinolones, third generation cephalosporins, and azithromycin. RECENT FINDINGS The last 40 years have witnessed the sequential emergence of resistance to all first-line antimicrobials used in the treatment of S. Typhi infections. Multidrug resistance (MDR), defined by resistance to chloramphenicol, amoxicillin, and co-trimoxazole, emerged in the 1990s, followed rapidly by reduced susceptibility to fluoroquinolones. In the current decade, high-level fluoroquinolone resistance has emerged in south Asia and threatens to spread worldwide. Increasing reliance is now being placed on the activity of third generation cephalosporins and azithromycin, but resistance against these agents is developing. Carbapenems and tigecycline may be alternatives, although clinical data are sparse, and in some settings reversion to chloramphenicol and co-trimoxazole susceptibility is occurring. Therefore, older drugs may yet have a role in the treatment of S. Typhi infections. SUMMARY Good surveillance, improved diagnostics, more prudent use of antimicrobials, and effective vaccines will all be critical to reducing the burden of disease caused by S. Typhi.
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Darton TC, Jones C, Dongol S, Voysey M, Blohmke CJ, Shrestha R, Karkey A, Shakya M, Arjyal A, Waddington CS, Gibani M, Carter MJ, Basnyat B, Baker S, Pollard AJ. Assessment and Translation of the Antibody-in-Lymphocyte Supernatant (ALS) Assay to Improve the Diagnosis of Enteric Fever in Two Controlled Human Infection Models and an Endemic Area of Nepal. Front Microbiol 2017; 8:2031. [PMID: 29109704 PMCID: PMC5660281 DOI: 10.3389/fmicb.2017.02031] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2016] [Accepted: 10/04/2017] [Indexed: 11/17/2022] Open
Abstract
New diagnostic tests for enteric fever are urgently needed to assist with timely antimicrobial treatment of patients and to measure the efficacy of prevention measures such as vaccination. In a novel translational approach, here we use two recently developed controlled human infection models (CHIM) of enteric fever to evaluate an antibody-in-lymphocyte supernatant (ALS) assay, which can detect recent IgA antibody production by circulating B cells in ex vivo mononuclear cell culture. We calculated the discriminative ability of the ALS assay to distinguish diagnosed cases in the two CHIM studies in Oxford, prior to evaluating blood culture-confirmed diagnoses of patients presenting with fever to hospital in an endemic areas of Kathmandu, Nepal. Antibody responses to membrane preparations and lipopolysaccharide provided good sensitivity (>90%) for diagnosing systemic infection after oral challenge with Salmonella Typhi or S. Paratyphi A. Assay specificity was moderate (~60%) due to imperfect sensitivity of blood culture as the reference standard and likely unrecognized subclinical infection. These findings were augmented through the translation of the assay into the endemic setting in Nepal. Anti-MP IgA responses again exhibited good sensitivity (86%) but poor specificity (51%) for detecting blood culture-confirmed enteric fever cases (ROC AUC 0.79, 95%CI 0.70–0.88). Patients with anti-MP IgA ALS titers in the upper quartile exhibited a clinical syndrome synonymous with enteric fever. While better reference standards are need to assess enteric fever diagnostics, routine use of this ALS assay could be used to rule out infection and has the potential to double the laboratory detection rate of enteric fever in this setting over blood culture alone.
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Affiliation(s)
- Thomas C Darton
- Oxford Vaccine Group, Centre for Clinical Vaccinology and Tropical Medicine, Department of Paediatrics, University of Oxford, National Institute for Health Research Oxford Biomedical Research Centre, Oxford, United Kingdom.,Wellcome Trust Major Overseas Programme, Hospital for Tropical Diseases, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam.,Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield, Sheffield, United Kingdom
| | - Claire Jones
- Oxford Vaccine Group, Centre for Clinical Vaccinology and Tropical Medicine, Department of Paediatrics, University of Oxford, National Institute for Health Research Oxford Biomedical Research Centre, Oxford, United Kingdom
| | - Sabina Dongol
- Oxford University Clinical Research Unit, Patan Academy of Health Sciences, Kathmandu, Nepal
| | - Merryn Voysey
- Oxford Vaccine Group, Centre for Clinical Vaccinology and Tropical Medicine, Department of Paediatrics, University of Oxford, National Institute for Health Research Oxford Biomedical Research Centre, Oxford, United Kingdom.,Nuffield Department of Primary Care Health Sciences, University of Oxford, Oxford, United Kingdom
| | - Christoph J Blohmke
- Oxford Vaccine Group, Centre for Clinical Vaccinology and Tropical Medicine, Department of Paediatrics, University of Oxford, National Institute for Health Research Oxford Biomedical Research Centre, Oxford, United Kingdom
| | - Rajendra Shrestha
- Oxford University Clinical Research Unit, Patan Academy of Health Sciences, Kathmandu, Nepal
| | - Abhilasha Karkey
- Wellcome Trust Major Overseas Programme, Hospital for Tropical Diseases, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam.,Oxford University Clinical Research Unit, Patan Academy of Health Sciences, Kathmandu, Nepal
| | - Mila Shakya
- Oxford University Clinical Research Unit, Patan Academy of Health Sciences, Kathmandu, Nepal
| | - Amit Arjyal
- Oxford University Clinical Research Unit, Patan Academy of Health Sciences, Kathmandu, Nepal
| | - Claire S Waddington
- Oxford Vaccine Group, Centre for Clinical Vaccinology and Tropical Medicine, Department of Paediatrics, University of Oxford, National Institute for Health Research Oxford Biomedical Research Centre, Oxford, United Kingdom
| | - Malick Gibani
- Oxford Vaccine Group, Centre for Clinical Vaccinology and Tropical Medicine, Department of Paediatrics, University of Oxford, National Institute for Health Research Oxford Biomedical Research Centre, Oxford, United Kingdom
| | - Michael J Carter
- Oxford Vaccine Group, Centre for Clinical Vaccinology and Tropical Medicine, Department of Paediatrics, University of Oxford, National Institute for Health Research Oxford Biomedical Research Centre, Oxford, United Kingdom.,Oxford University Clinical Research Unit, Patan Academy of Health Sciences, Kathmandu, Nepal
| | - Buddha Basnyat
- Oxford University Clinical Research Unit, Patan Academy of Health Sciences, Kathmandu, Nepal
| | - Stephen Baker
- Wellcome Trust Major Overseas Programme, Hospital for Tropical Diseases, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
| | - Andrew J Pollard
- Oxford Vaccine Group, Centre for Clinical Vaccinology and Tropical Medicine, Department of Paediatrics, University of Oxford, National Institute for Health Research Oxford Biomedical Research Centre, Oxford, United Kingdom
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Darton TC, Baker S, Randall A, Dongol S, Karkey A, Voysey M, Carter MJ, Jones C, Trappl K, Pablo J, Hung C, Teng A, Shandling A, Le T, Walker C, Molina D, Andrews J, Arjyal A, Basnyat B, Pollard AJ, Blohmke CJ. Identification of Novel Serodiagnostic Signatures of Typhoid Fever Using a Salmonella Proteome Array. Front Microbiol 2017; 8:1794. [PMID: 28970824 PMCID: PMC5609549 DOI: 10.3389/fmicb.2017.01794] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2017] [Accepted: 09/05/2017] [Indexed: 11/26/2022] Open
Abstract
Current diagnostic tests for typhoid fever, the disease caused by Salmonella Typhi, are poor. We aimed to identify serodiagnostic signatures of typhoid fever by assessing microarray signals to 4,445 S. Typhi antigens in sera from 41 participants challenged with oral S. Typhi. We found broad, heterogeneous antibody responses with increasing IgM/IgA signals at diagnosis. In down-selected 250-antigen arrays we validated responses in a second challenge cohort (n = 30), and selected diagnostic signatures using machine learning and multivariable modeling. In four models containing responses to antigens including flagellin, OmpA, HlyE, sipC, and LPS, multi-antigen signatures discriminated typhoid (n = 100) from other febrile bacteremia (n = 52) in Nepal. These models contained combinatorial IgM, IgA, and IgG responses to 5 antigens (ROC AUC, 0.67 and 0.71) or 3 antigens (0.87), although IgA responses to LPS also performed well (0.88). Using a novel systematic approach we have identified and validated optimal serological diagnostic signatures of typhoid fever.
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Affiliation(s)
- Thomas C Darton
- Oxford Vaccine Group, Centre for Clinical Vaccinology and Tropical Medicine, Department of Paediatrics, and the Oxford National Institutes for Health Research Biomedical Research Centre, University of OxfordOxford, United Kingdom.,The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research UnitHo Chi Minh City, Vietnam.,Department of Infection, Immunity and Cardiovascular Disease, The University of SheffieldSheffield, United Kingdom
| | - Stephen Baker
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research UnitHo Chi Minh City, Vietnam
| | - Arlo Randall
- Antigen Discovery Incorporated, IrvineCA, United States
| | - Sabina Dongol
- Oxford University Clinical Research Unit, Patan Academy of Health SciencesKathmandu, Nepal
| | - Abhilasha Karkey
- Oxford University Clinical Research Unit, Patan Academy of Health SciencesKathmandu, Nepal
| | - Merryn Voysey
- Oxford Vaccine Group, Centre for Clinical Vaccinology and Tropical Medicine, Department of Paediatrics, and the Oxford National Institutes for Health Research Biomedical Research Centre, University of OxfordOxford, United Kingdom.,Nuffield Department of Primary Care Health Sciences, University of OxfordOxford, United Kingdom
| | - Michael J Carter
- Oxford Vaccine Group, Centre for Clinical Vaccinology and Tropical Medicine, Department of Paediatrics, and the Oxford National Institutes for Health Research Biomedical Research Centre, University of OxfordOxford, United Kingdom
| | - Claire Jones
- Oxford Vaccine Group, Centre for Clinical Vaccinology and Tropical Medicine, Department of Paediatrics, and the Oxford National Institutes for Health Research Biomedical Research Centre, University of OxfordOxford, United Kingdom
| | - Krista Trappl
- Antigen Discovery Incorporated, IrvineCA, United States
| | - Jozelyn Pablo
- Antigen Discovery Incorporated, IrvineCA, United States
| | - Chris Hung
- Antigen Discovery Incorporated, IrvineCA, United States
| | - Andy Teng
- Antigen Discovery Incorporated, IrvineCA, United States
| | | | - Tim Le
- Antigen Discovery Incorporated, IrvineCA, United States
| | | | | | - Jason Andrews
- Division of Infectious Diseases and Geographic Medicine, Stanford University, StanfordCA, United States
| | - Amit Arjyal
- Nuffield Department of Primary Care Health Sciences, University of OxfordOxford, United Kingdom
| | - Buddha Basnyat
- Nuffield Department of Primary Care Health Sciences, University of OxfordOxford, United Kingdom
| | - Andrew J Pollard
- Oxford Vaccine Group, Centre for Clinical Vaccinology and Tropical Medicine, Department of Paediatrics, and the Oxford National Institutes for Health Research Biomedical Research Centre, University of OxfordOxford, United Kingdom
| | - Christoph J Blohmke
- Oxford Vaccine Group, Centre for Clinical Vaccinology and Tropical Medicine, Department of Paediatrics, and the Oxford National Institutes for Health Research Biomedical Research Centre, University of OxfordOxford, United Kingdom
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A cross-sectional seroepidemiological survey of typhoid fever in Fiji. PLoS Negl Trop Dis 2017; 11:e0005786. [PMID: 28727726 PMCID: PMC5549756 DOI: 10.1371/journal.pntd.0005786] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2017] [Revised: 08/08/2017] [Accepted: 07/06/2017] [Indexed: 12/26/2022] Open
Abstract
Fiji, an upper-middle income state in the Pacific Ocean, has experienced an increase in confirmed case notifications of enteric fever caused by Salmonella enterica serovar Typhi (S. Typhi). To characterize the epidemiology of typhoid exposure, we conducted a cross-sectional sero-epidemiological survey measuring IgG against the Vi antigen of S. Typhi to estimate the effect of age, ethnicity, and other variables on seroprevalence. Epidemiologically relevant cut-off titres were established using a mixed model analysis of data from recovering culture-confirmed typhoid cases. We enrolled and assayed plasma of 1787 participants for anti-Vi IgG; 1,531 of these were resident in mainland areas that had not been previously vaccinated against S. Typhi (seropositivity 32.3% (95%CI 28.2 to 36.3%)), 256 were resident on Taveuni island, which had been previously vaccinated (seropositivity 71.5% (95%CI 62.1 to 80.9%)). The seroprevalence on the Fijian mainland is one to two orders of magnitude higher than expected from confirmed case surveillance incidence, suggesting substantial subclinical or otherwise unreported typhoid. We found no significant differences in seropositivity prevalences by ethnicity, which is in contrast to disease surveillance data in which the indigenous iTaukei Fijian population are disproportionately affected. Using multivariable logistic regression, seropositivity was associated with increased age (odds ratio 1.3 (95% CI 1.2 to 1.4) per 10 years), the presence of a pit latrine (OR 1.6, 95%CI 1.1 to 2.3) as opposed to a septic tank or piped sewer, and residence in settlements rather than residential housing or villages (OR 1.6, 95% CI 1.0 to 2.7). Increasing seropositivity with age is suggestive of low-level endemic transmission in Fiji. Improved sanitation where pit latrines are used and addressing potential transmission routes in settlements may reduce exposure to S. Typhi. Widespread unreported infection suggests there may be a role for typhoid vaccination in Fiji, in addition to public health management of cases and outbreaks. Fiji has experienced a decade-long increase in typhoid fever cases, a potentially life-threatening systemic bacterial disease caused by Salmonella Typhi. We undertook a representative blood-serum community survey to measure antibodies (IgG) against the Vi antigen of Salmonella Typhi using a rigorous survey design. We found one in three residents of mainland, unvaccinated Fiji had detectable antibody against Vi. This was higher than would be expected from confirmed case notifications received by the national surveillance system. Additionally, similar antibody responses were detected in Fijians of all ethnicities, which contrasts to surveillance cases in which indigenous iTaukei Fijians were disproportionately affected. Serology on a Fijian island where a significant proportion of the population has been vaccinated found that three-quarters of residents were seropositive three years after the Vi-polysaccharide typhoid vaccination campaign. Importantly, in mainland participants, seroprevalence increased with age, suggesting long-standing, low-level, endemic transmission. Pit latrines were associated with seropositivity when compared with septic tanks, and settlements compared with residential housing. Very high antibody titres in a small percentage of participants may suggest carriage of Salmonella Typhi. The seroprevalence findings suggest eliminating typhoid from Fiji by focussing on cases and outbreaks alone will be challenging. Our results support typhoid vaccination and further development of water, sanitation and hygiene infrastructure in Fiji.
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Darton TC, Meiring JE, Tonks S, Khan MA, Khanam F, Shakya M, Thindwa D, Baker S, Basnyat B, Clemens JD, Dougan G, Dolecek C, Dunstan SJ, Gordon MA, Heyderman RS, Holt KE, Pitzer VE, Qadri F, Zaman K, Pollard AJ. The STRATAA study protocol: a programme to assess the burden of enteric fever in Bangladesh, Malawi and Nepal using prospective population census, passive surveillance, serological studies and healthcare utilisation surveys. BMJ Open 2017; 7:e016283. [PMID: 28674145 PMCID: PMC5726077 DOI: 10.1136/bmjopen-2017-016283] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
INTRODUCTION Invasive infections caused by Salmonella enterica serovar Typhi and Paratyphi A are estimated to account for 12-27 million febrile illness episodes worldwide annually. Determining the true burden of typhoidal Salmonellae infections is hindered by lack of population-based studies and adequate laboratory diagnostics.The Strategic Typhoid alliance across Africa and Asia study takes a systematic approach to measuring the age-stratified burden of clinical and subclinical disease caused by typhoidal Salmonellae infections at three high-incidence urban sites in Africa and Asia. We aim to explore the natural history of Salmonella transmission in endemic settings, addressing key uncertainties relating to the epidemiology of enteric fever identified through mathematical models, and enabling optimisation of vaccine strategies. METHODS/DESIGN Using census-defined denominator populations of ≥100 000 individuals at sites in Malawi, Bangladesh and Nepal, the primary outcome is to characterise the burden of enteric fever in these populations over a 24-month period. During passive surveillance, clinical and household data, and laboratory samples will be collected from febrile individuals. In parallel, healthcare utilisation and water, sanitation and hygiene surveys will be performed to characterise healthcare-seeking behaviour and assess potential routes of transmission. The rates of both undiagnosed and subclinical exposure to typhoidal Salmonellae (seroincidence), identification of chronic carriage and population seroprevalence of typhoid infection will be assessed through age-stratified serosurveys performed at each site. Secondary attack rates will be estimated among household contacts of acute enteric fever cases and possible chronic carriers. ETHICS AND DISSEMINATION This protocol has been ethically approved by the Oxford Tropical Research Ethics Committee, the icddr,b Institutional Review Board, the Malawian National Health Sciences Research Committee and College of Medicine Research Ethics Committee and Nepal Health Research Council. The study is being conducted in accordance with the principles of the Declaration of Helsinki and Good Clinical Practice. Informed consent was obtained before study enrolment. Results will be submitted to international peer-reviewed journals and presented at international conferences. TRIAL REGISTRATION NUMBER ISRCTN 12131979. ETHICS REFERENCES Oxford (Oxford Tropical Research Ethics Committee 39-15).Bangladesh (icddr,b Institutional Review Board PR-15119).Malawi (National Health Sciences Research Committee 15/5/1599).Nepal (Nepal Health Research Council 306/2015).
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Affiliation(s)
- Thomas C Darton
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
- Department of Paediatrics, Oxford Vaccine Group, University of Oxford, and the NIHR Oxford Biomedical Research Centre, Oxford, UK
- Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield Medical School, Sheffield, UK
| | - James E Meiring
- Department of Paediatrics, Oxford Vaccine Group, University of Oxford, and the NIHR Oxford Biomedical Research Centre, Oxford, UK
| | - Susan Tonks
- Department of Paediatrics, Oxford Vaccine Group, University of Oxford, and the NIHR Oxford Biomedical Research Centre, Oxford, UK
| | | | - Farhana Khanam
- International Centre for Diarrhoeal Diseases Research, Dhaka, Bangladesh
| | - Mila Shakya
- Oxford University Clinical Research Unit, Patan Academy of Health Sciences, Kathmandu, Nepal
| | - Deus Thindwa
- Malawi Liverpool Wellcome Trust Clinical Research Programme, University of Malawi College of Medicine, Blantyre, Malawi
| | - Stephen Baker
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
- Nuffield Department of Medicine, Centre for Tropical Medicine and Global Health, University of Oxford, Oxford, UK
- The Wellcome Trust Sanger Institute, Cambridgeshire, UK
| | - Buddha Basnyat
- Oxford University Clinical Research Unit, Patan Academy of Health Sciences, Kathmandu, Nepal
- Nuffield Department of Medicine, Centre for Tropical Medicine and Global Health, University of Oxford, Oxford, UK
| | - John D Clemens
- International Centre for Diarrhoeal Diseases Research, Dhaka, Bangladesh
- UCLA Fielding School of Public Health, Los Angeles, USA
| | - Gordon Dougan
- The Wellcome Trust Sanger Institute, Cambridgeshire, UK
| | - Christiane Dolecek
- Nuffield Department of Medicine, Centre for Tropical Medicine and Global Health, University of Oxford, Oxford, UK
- Mahidol-Oxford Tropical Medicine Research Unit, Mahidol University, Bangkok, Thailand
| | - Sarah J Dunstan
- The Peter Doherty Institute for Infection and Immunity, The University of Melbourne, Melbourne, Australia
| | - Melita A Gordon
- Malawi Liverpool Wellcome Trust Clinical Research Programme, University of Malawi College of Medicine, Blantyre, Malawi
- Institute of Infection and Global Health, University of Liverpool, Liverpool, UK
| | - Robert S Heyderman
- Malawi Liverpool Wellcome Trust Clinical Research Programme, University of Malawi College of Medicine, Blantyre, Malawi
- Division of Infection and Immunity, University College London, London, UK
| | - Kathryn E Holt
- Centre for Systems Genomics, University of Melbourne, Victoria, Australia
- Department of Biochemistry and Molecular Biology, University of Melbourne, Victoria, Australia
| | - Virginia E Pitzer
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, Yale University, New Haven, Connecticut, USA
| | - Firdausi Qadri
- International Centre for Diarrhoeal Diseases Research, Dhaka, Bangladesh
| | - K Zaman
- International Centre for Diarrhoeal Diseases Research, Dhaka, Bangladesh
| | - Andrew J Pollard
- Department of Paediatrics, Oxford Vaccine Group, University of Oxford, and the NIHR Oxford Biomedical Research Centre, Oxford, UK
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Abstract
BACKGROUND Differentiating both typhoid (Salmonella Typhi) and paratyphoid (Salmonella Paratyphi A) infection from other causes of fever in endemic areas is a diagnostic challenge. Although commercial point-of-care rapid diagnostic tests (RDTs) for enteric fever are available as alternatives to the current reference standard test of blood or bone marrow culture, or to the widely used Widal Test, their diagnostic accuracy is unclear. If accurate, they could potentially replace blood culture as the World Health Organization (WHO)-recommended main diagnostic test for enteric fever. OBJECTIVES To assess the diagnostic accuracy of commercially available rapid diagnostic tests (RDTs) and prototypes for detecting Salmonella Typhi or Paratyphi A infection in symptomatic persons living in endemic areas. SEARCH METHODS We searched the Cochrane Infectious Diseases Group Specialized Register, MEDLINE, Embase, Science Citation Index, IndMED, African Index Medicus, LILACS, ClinicalTrials.gov, and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) up to 4 March 2016. We manually searched WHO reports, and papers from international conferences on Salmonella infections. We also contacted test manufacturers to identify studies. SELECTION CRITERIA We included diagnostic accuracy studies of enteric fever RDTs in patients with fever or with symptoms suggestive of enteric fever living in endemic areas. We classified the reference standard used as either Grade 1 (result from a blood culture and a bone marrow culture) or Grade 2 (result from blood culture and blood polymerase chain reaction, or from blood culture alone). DATA COLLECTION AND ANALYSIS Two review authors independently extracted the test result data. We used a modified QUADAS-2 extraction form to assess methodological quality. We performed a meta-analysis when there were sufficient studies for the test and heterogeneity was reasonable. MAIN RESULTS Thirty-seven studies met the inclusion criteria and included a total of 5080 participants (range 50 to 1732). Enteric fever prevalence rates in the study populations ranged from 1% to 75% (median prevalence 24%, interquartile range (IQR) 11% to 46%). The included studies evaluated 16 different RDTs, and 16 studies compared two or more different RDTs. Only three studies used the Grade 1 reference standard, and only 11 studies recruited unselected febrile patients. Most included studies were from Asia, with five studies from sub-Saharan Africa. All of the RDTs were designed to detect S.Typhi infection only.Most studies evaluated three RDTs and their variants: TUBEX in 14 studies; Typhidot (Typhidot, Typhidot-M, and TyphiRapid-Tr02) in 22 studies; and the Test-It Typhoid immunochromatographic lateral flow assay, and its earlier prototypes (dipstick, latex agglutination) developed by the Royal Tropical Institute, Amsterdam (KIT) in nine studies. Meta-analyses showed an average sensitivity of 78% (95% confidence interval (CI) 71% to 85%) and specificity of 87% (95% CI 82% to 91%) for TUBEX; and an average sensitivity of 69% (95% CI 59% to 78%) and specificity of 90% (95% CI 78% to 93%) for all Test-It Typhoid and prototype tests (KIT). Across all forms of the Typhidot test, the average sensitivity was 84% (95% CI 73% to 91%) and specificity was 79% (95% CI 70% to 87%). When we based the analysis on the 13 studies of the Typhidot test that either reported indeterminate test results or where the test format means there are no indeterminate results, the average sensitivity was 78% (95% CI 65% to 87%) and specificity was 77% (95% CI 66% to 86%). We did not identify any difference in either sensitivity or specificity between TUBEX, Typhidot, and Test-it Typhoid tests when based on comparison to the 13 Typhidot studies where indeterminate results are either reported or not applicable. If TUBEX and Test-it Typhoid are compared to all Typhidot studies, the sensitivity of Typhidot was higher than Test-it Typhoid (15% (95% CI 2% to 28%), but other comparisons did not show a difference at the 95% level of CIs.In a hypothetical cohort of 1000 patients presenting with fever where 30% (300 patients) have enteric fever, on average Typhidot tests reporting indeterminate results or where tests do not produce indeterminate results will miss the diagnosis in 66 patients with enteric fever, TUBEX will miss 66, and Test-It Typhoid and prototype (KIT) tests will miss 93. In the 700 people without enteric fever, the number of people incorrectly diagnosed with enteric fever would be 161 with Typhidot tests, 91 with TUBEX, and 70 with Test-It Typhoid and prototype (KIT) tests. The CIs around these estimates were wide, with no difference in false positive results shown between tests.The quality of the data for each study was evaluated using a standardized checklist called QUADAS-2. Overall, the certainty of the evidence in the studies that evaluated enteric fever RDTs was low. AUTHORS' CONCLUSIONS In 37 studies that evaluated the diagnostic accuracy of RDTs for enteric fever, few studies were at a low risk of bias. The three main RDT tests and variants had moderate diagnostic accuracy. There was no evidence of a difference between the average sensitivity and specificity of the three main RDT tests. More robust evaluations of alternative RDTs for enteric fever are needed.
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Affiliation(s)
- Lalith Wijedoru
- Liverpool School of Tropical MedicineDepartment of Clinical SciencesLiverpoolUKL3 5QA
| | - Sue Mallett
- University of BirminghamInstitute of Applied Health SciencesEdgbastonBirminghamUKB15 2TT
| | - Christopher M Parry
- Liverpool School of Tropical MedicineDepartment of Clinical SciencesLiverpoolUKL3 5QA
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32
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Tran Vu Thieu N, Trinh Van T, Tran Tuan A, Klemm EJ, Nguyen Ngoc Minh C, Voong Vinh P, Pham Thanh D, Ho Ngoc Dan T, Pham Duc T, Langat P, Martin LB, Galan J, Liang L, Felgner PL, Davies DH, de Jong HK, Maude RR, Fukushima M, Wijedoru L, Ghose A, Samad R, Dondorp AM, Faiz A, Darton TC, Pollard AJ, Thwaites GE, Dougan G, Parry CM, Baker S. An evaluation of purified Salmonella Typhi protein antigens for the serological diagnosis of acute typhoid fever. J Infect 2017; 75:104-114. [PMID: 28551371 PMCID: PMC5522525 DOI: 10.1016/j.jinf.2017.05.007] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2017] [Revised: 05/15/2017] [Accepted: 05/16/2017] [Indexed: 12/14/2022]
Abstract
Objectives The diagnosis of typhoid fever is a challenge. Aiming to develop a typhoid diagnostic we measured antibody responses against Salmonella Typhi (S. Typhi) protein antigens and the Vi polysaccharide in a cohort of Bangladeshi febrile patients. Methods IgM against 12 purified antigens and the Vi polysaccharide was measured by ELISA in plasma from patients with confirmed typhoid fever (n = 32), other confirmed infections (n = 17), and healthy controls (n = 40). ELISAs with the most specific antigens were performed on plasma from 243 patients with undiagnosed febrile disease. Results IgM against the S. Typhi protein antigens correlated with each other (rho > 0.8), but not against Vi (rho < 0.6). Typhoid patients exhibited higher IgM against 11/12 protein antigens and Vi than healthy controls and those with other infections. Vi, PilL, and CdtB exhibited the greatest sensitivity and specificity. Specificity and sensitivity was improved when Vi was combined with a protein antigen, generating sensitivities and specificities of 0.80 and >0.85, respectively. Applying a dynamic cut-off to patients with undiagnosed febrile disease suggested that 34–58% had an IgM response indicative of typhoid. Conclusions We evaluated the diagnostic potential of several S. Typhi antigens; our assays give good sensitivity and specificity, but require further assessment in differing patient populations.
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Affiliation(s)
- Nga Tran Vu Thieu
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Viet Nam
| | - Tan Trinh Van
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Viet Nam
| | - Anh Tran Tuan
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Viet Nam
| | - Elizabeth J Klemm
- The Wellcome Trust Sanger Institute, Hinxton, Cambridgeshire, United Kingdom
| | - Chau Nguyen Ngoc Minh
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Viet Nam
| | - Phat Voong Vinh
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Viet Nam
| | - Duy Pham Thanh
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Viet Nam
| | - Thanh Ho Ngoc Dan
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Viet Nam
| | - Trung Pham Duc
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Viet Nam
| | - Pinky Langat
- The Wellcome Trust Sanger Institute, Hinxton, Cambridgeshire, United Kingdom
| | - Laura B Martin
- Sclavo Berhing Vaccines Institute for Global Health, Siena, Italy
| | - Jorge Galan
- Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, CT, USA
| | - Li Liang
- Department of Medicine, Division of Infectious Diseases, University of California, Irvine, CA, USA
| | - Philip L Felgner
- Department of Medicine, Division of Infectious Diseases, University of California, Irvine, CA, USA
| | - D Huw Davies
- Department of Medicine, Division of Infectious Diseases, University of California, Irvine, CA, USA
| | - Hanna K de Jong
- Department of Internal Medicine, Division of Infectious Diseases and Center for Infection and Immunity Amsterdam (CINIMA), Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Rapeephan R Maude
- Mahidol-Oxford Tropical Medicine Research Unit (MORU), Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand; Centre for Tropical Medicine and Global Health, Oxford University, Oxford, United Kingdom
| | - Masako Fukushima
- Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Lalith Wijedoru
- Mahidol-Oxford Tropical Medicine Research Unit (MORU), Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | | | - Rasheda Samad
- Chittagong Medical College Hospital, Chittagong, Bangladesh
| | - Arjen M Dondorp
- Mahidol-Oxford Tropical Medicine Research Unit (MORU), Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand; Malaria Research Group and Dev Care Foundation, Bangladesh
| | - Abul Faiz
- Malaria Research Group and Dev Care Foundation, Bangladesh
| | - Thomas C Darton
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Viet Nam; Sheffield Teaching Hospitals NHS Trust Foundation and the University of Sheffield, Sheffield, United Kingdom
| | - Andrew J Pollard
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford and the NIHR Oxford Biomedical Research Centre, Oxford, United Kingdom
| | - Guy E Thwaites
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Viet Nam; Centre for Tropical Medicine and Global Health, Oxford University, Oxford, United Kingdom
| | - Gordon Dougan
- The Wellcome Trust Sanger Institute, Hinxton, Cambridgeshire, United Kingdom; The Department of Medicine, University of Cambridge, Cambridge, United Kingdom
| | - Christopher M Parry
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford and the NIHR Oxford Biomedical Research Centre, Oxford, United Kingdom
| | - Stephen Baker
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Viet Nam; Centre for Tropical Medicine and Global Health, Oxford University, Oxford, United Kingdom; The Department of Medicine, University of Cambridge, Cambridge, United Kingdom.
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Näsström E, Parry CM, Vu Thieu NT, Maude RR, de Jong HK, Fukushima M, Rzhepishevska O, Marks F, Panzner U, Im J, Jeon H, Park S, Chaudhury Z, Ghose A, Samad R, Van TT, Johansson A, Dondorp AM, Thwaites GE, Faiz A, Antti H, Baker S. Reproducible diagnostic metabolites in plasma from typhoid fever patients in Asia and Africa. eLife 2017; 6. [PMID: 28483042 PMCID: PMC5423768 DOI: 10.7554/elife.15651] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2016] [Accepted: 04/17/2017] [Indexed: 11/13/2022] Open
Abstract
Salmonella Typhi is the causative agent of typhoid. Typhoid is diagnosed by blood culture, a method that lacks sensitivity, portability and speed. We have previously shown that specific metabolomic profiles can be detected in the blood of typhoid patients from Nepal (Näsström et al., 2014). Here, we performed mass spectrometry on plasma from Bangladeshi and Senegalese patients with culture confirmed typhoid fever, clinically suspected typhoid, and other febrile diseases including malaria. After applying supervised pattern recognition modelling, we could significantly distinguish metabolite profiles in plasma from the culture confirmed typhoid patients. After comparing the direction of change and degree of multivariate significance, we identified 24 metabolites that were consistently up- or down regulated in a further Bangladeshi/Senegalese validation cohort, and the Nepali cohort from our previous work. We have identified and validated a metabolite panel that can distinguish typhoid from other febrile diseases, providing a new approach for typhoid diagnostics.
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Affiliation(s)
- Elin Näsström
- Department of Chemistry, Computational Life Science Cluster, Umeå University, Umeå, Sweden
| | - Christopher M Parry
- Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, United Kingdom.,School of Tropical Medicine and Global Health, Nagasaki University, Nagasaki, Japan
| | - Nga Tran Vu Thieu
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University, Oxford, United Kingdom.,Clinical Research Unit, Ho Chi Minh City, Vietnam
| | - Rapeephan R Maude
- Mahidol-Oxford Tropical Medicine Research Unit (MORU), Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Hanna K de Jong
- Department of Internal Medicine, Division of Infectious Diseases and Center for Infection and Immunity Amsterdam (CINIMA), University of Amsterdam, Amsterdam, the Netherlands.,Center for Experimental Molecular Medicine (CEMM), Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Masako Fukushima
- Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Olena Rzhepishevska
- Department of Chemistry, Computational Life Science Cluster, Umeå University, Umeå, Sweden
| | - Florian Marks
- The International Vaccine Institute, Seoul, South Korea
| | | | - Justin Im
- The International Vaccine Institute, Seoul, South Korea
| | - Hyonjin Jeon
- The International Vaccine Institute, Seoul, South Korea
| | - Seeun Park
- The International Vaccine Institute, Seoul, South Korea
| | | | | | - Rasheda Samad
- Chittagong Medical College Hospital, Chittagong, Bangladesh
| | - Tan Trinh Van
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University, Oxford, United Kingdom
| | - Anders Johansson
- Department of Clinical Microbiology, Umeå University, Umeå, Sweden
| | - Arjen M Dondorp
- Mahidol-Oxford Tropical Medicine Research Unit (MORU), Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Guy E Thwaites
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University, Oxford, United Kingdom.,Centre for Tropical Medicine, Oxford University, Oxford, United Kingdom
| | - Abul Faiz
- Malaria Research Group and Dev Care Foundation, Dhaka, Bangladesh
| | - Henrik Antti
- Department of Chemistry, Computational Life Science Cluster, Umeå University, Umeå, Sweden
| | - Stephen Baker
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University, Oxford, United Kingdom.,Centre for Tropical Medicine, Oxford University, Oxford, United Kingdom.,Department of Medicine, The University of Cambridge, Cambridge, United Kingdom
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Chiyangi H, Muma JB, Malama S, Manyahi J, Abade A, Kwenda G, Matee MI. Identification and antimicrobial resistance patterns of bacterial enteropathogens from children aged 0-59 months at the University Teaching Hospital, Lusaka, Zambia: a prospective cross sectional study. BMC Infect Dis 2017; 17:117. [PMID: 28152988 PMCID: PMC5290660 DOI: 10.1186/s12879-017-2232-0] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2016] [Accepted: 01/31/2017] [Indexed: 11/25/2022] Open
Abstract
BACKGROUND Bacterial diarrhoeal disease is among the most common causes of mortality and morbidity in children 0-59 months at the University Teaching Hospital in Lusaka, Zambia. However, most cases are treated empirically without the knowledge of aetiological agents or antimicrobial susceptibility patterns. The aim of this study was, therefore, to identify bacterial causes of diarrhoea and determine their antimicrobial susceptibility patterns in stool specimens obtained from the children at the hospital. METHODS This hospital-based cross-sectional study involved children aged 0-59 months presenting with diarrhoea at paediatrics wards at the University Teaching Hospital in Lusaka, Zambia, from January to May 2016. Stool samples were cultured on standard media for enteropathogenic bacteria, and identified further by biochemical tests. Multiplex polymerase chain reaction was used for characterization of diarrhoeagenic Escherichia coli strains. Antimicrobial susceptibility testing was performed on antibiotics that are commonly prescribed at the hospital using the Kirby-Bauer disc diffusion method, which was performed using the Clinical Laboratory Standards International guidelines. RESULTS Of the 271 stool samples analysed Vibrio cholerae 01 subtype and Ogawa serotype was the most commonly detected pathogen (40.8%), followed by Salmonella species (25.5%), diarrhoeagenic Escherichia coli (18%), Shigella species (14.4%) and Campylobacter species (3.5%). The majority of the bacterial pathogens were resistant to two or more drugs tested, with ampicillin and co-trimoxazole being the most ineffective drugs. All diarrhoeagenic Escherichia coli isolates were extended spectrum β-lactamase producers. CONCLUSION Five different groups of bacterial pathogens were isolated from the stool specimens, and the majority of these organisms were multidrug resistant. These data calls for urgent revision of the current empiric treatment of diarrhoea in children using ampicillin and co-trimoxazole, and emphasizes the need for continuous antimicrobial surveillance as well as the implementation of prevention programmes for childhood diarrhoea.
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Affiliation(s)
- Harriet Chiyangi
- Department of Epidemiology and Biostatistics, School of Public Health and Social Sciences, Muhimbili University of Health and Allied Science, Dar es Salaam, Tanzania
- Tanzania Field Epidemiology and Laboratory Management Program, Ministry of Health, Dar es Salaam, Tanzania
| | - John B Muma
- Department of Disease Control, School of Veterinary, University of Zambia, Lusaka, Zambia
| | - Sydney Malama
- Health Promotions Research Program, Institute of Economic and Social Research, University of Zambia, Lusaka, Zambia.
| | - Joel Manyahi
- Health Promotions Research Program, Institute of Economic and Social Research, University of Zambia, Lusaka, Zambia
| | - Ahmed Abade
- Tanzania Field Epidemiology and Laboratory Management Program, Ministry of Health, Dar es Salaam, Tanzania
| | - Geoffrey Kwenda
- Department of Biomedical Sciences, School of Health Sciences, University of Zambia, Lusaka, Zambia
| | - Mecky I Matee
- Department of Microbiology and Immunology, School of Medicine, Muhimbili University of Health and Allied Science, Dar es Salaam, Tanzania
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Darton TC, Zhou L, Blohmke CJ, Jones C, Waddington CS, Baker S, Pollard AJ. Blood culture-PCR to optimise typhoid fever diagnosis after controlled human infection identifies frequent asymptomatic cases and evidence of primary bacteraemia. J Infect 2017; 74:358-366. [PMID: 28130144 PMCID: PMC5345565 DOI: 10.1016/j.jinf.2017.01.006] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2016] [Revised: 01/11/2017] [Accepted: 01/14/2017] [Indexed: 01/09/2023]
Abstract
Background Improved diagnostics for typhoid are needed; a typhoid controlled human infection model may accelerate their development and translation. Here, we evaluated a blood culture-PCR assay for detecting infection after controlled human infection with S. Typhi and compared test performance with optimally performed blood cultures. Methodology/Principal findings Culture-PCR amplification of blood samples was performed alongside daily blood culture in 41 participants undergoing typhoid challenge. Study endpoints for typhoid diagnosis (TD) were fever and/or bacteraemia. Overall, 24/41 (59%) participants reached TD, of whom 21/24 (86%) had ≥1 positive blood culture (53/674, 7.9% of all cultures) or 18/24 (75%) had ≥1 positive culture-PCR assay result (57/684, 8.3%). A further five non-bacteraemic participants produced culture-PCR amplicons indicating infection; overall sensitivity/specificity of the assay compared to the study endpoints were 70%/65%. We found no significant difference between blood culture and culture-PCR methods in ability to identify cases (12 mismatching pairs, p = 0.77, binomial test). Clinical and stool culture metadata demonstrated that additional culture-PCR amplification positive individuals likely represented true cases missed by blood culture, suggesting the overall attack rate may be 30/41 (73%) rather than 24/41 (59%). Several participants had positive culture-PCR results soon after ingesting challenge providing new evidence for occurrence of an early primary bacteraemia. Conclusions/Significance Overall the culture-PCR assay performed well, identifying extra typhoid cases compared with routine blood culture alone. Despite limitations to widespread field-use, the benefits of increased diagnostic yield, reduced blood volume and faster turn-around-time, suggest that this assay could enhance laboratory typhoid diagnostics in research applications and high-incidence settings. Culture in ox-bile/tryptone soy broth selectively enriches for bile-tolerant Salmonella Typhi while lysing human cells. PCR sensitivity for detecting typhoid in clinical blood is limited by very low level bacteraemia during clinical illness. PCR amplification of S. Typhi fliC-d in pre-cultured blood can accurately identify typhoid infection in challenge study participants. Daily culture-PCR of blood collected from challenge study participants suggests primary bacteraemia occurs 12–36 h after S. Typhi ingestion. Additional use of culture-PCR demonstrates the true attack rate after typhoid challenge is markedly higher (75%) than previously assumed (60%).
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Affiliation(s)
- Thomas C Darton
- Oxford Vaccine Group, Department of Paediatrics and the NIHR Oxford Biomedical Research Centre, University of Oxford, Oxford, United Kingdom; The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Viet Nam.
| | - Liqing Zhou
- Oxford Vaccine Group, Department of Paediatrics and the NIHR Oxford Biomedical Research Centre, University of Oxford, Oxford, United Kingdom
| | - Christoph J Blohmke
- Oxford Vaccine Group, Department of Paediatrics and the NIHR Oxford Biomedical Research Centre, University of Oxford, Oxford, United Kingdom
| | - Claire Jones
- Oxford Vaccine Group, Department of Paediatrics and the NIHR Oxford Biomedical Research Centre, University of Oxford, Oxford, United Kingdom
| | - Claire S Waddington
- Oxford Vaccine Group, Department of Paediatrics and the NIHR Oxford Biomedical Research Centre, University of Oxford, Oxford, United Kingdom
| | - Stephen Baker
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Viet Nam; Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, Oxford University, Oxford, United Kingdom
| | - Andrew J Pollard
- Oxford Vaccine Group, Department of Paediatrics and the NIHR Oxford Biomedical Research Centre, University of Oxford, Oxford, United Kingdom
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Maheshwari V, Kaore NM, Ramnani VK, Sarda S. A Comparative Evaluation of Different Diagnostic Modalities in the Diagnosis of Typhoid Fever Using a Composite Reference Standard: A Tertiary Hospital Based Study in Central India. J Clin Diagn Res 2016; 10:DC01-DC04. [PMID: 27891335 DOI: 10.7860/jcdr/2016/20426.8684] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2016] [Accepted: 07/19/2016] [Indexed: 11/24/2022]
Abstract
INTRODUCTION Enteric fever, caused by Salmonella spp. is a major cause of morbidity and mortality worldwide and endemic in many developing countries including India and other South-East Asian countries. Blood culture is regarded as the gold standard for diagnosis. Currently, the standard serological method is tube agglutination with moderate sensitivity and specificity. Dot blot assay detecting IgM and IgG antibodies to a specific 50kD Outer Membrane Protein (OMP) antigen of Salmonella spp. is a simple, reliable, affordable and rapid test which can help in the early diagnosis of typhoid fever. AIM To systematically evaluate the different diagnostic modalities against a composite reference standard for the better diagnosis of typhoid fever in clinically suspected cases of typhoid fever. MATERIALS AND METHODS This cross-sectional, prospective analytical study was carried out at a tertiary care hospital attached to Medical College in central India from November 2011 to June 2013. A total of 163 blood samples, collected aseptically from patients clinically diagnosed of enteric fever, were tested using various component tests like blood culture, Tube Widal and Dot Enzyme Immuno Assay (Dot EIA) for IgG and/or IgM. Composite Reference Standard (CRS) was created for defining the confirmed cases of typhoid fever using the component tests, wherein culture positive and in absence of culture positivity any two component test positive patients were taken as confirmed cases. All the component tests were evaluated against the CRS for sensitivity, specificity, PPV and NPV and their significance in relation to the duration of illness using statistical tests of significance. RESULTS Blood culture was positive in 16 (9.81%) whereas, Tube Widal, IgM, IgG and IgM+IgG in combination were positive in 88(54%), 58(35.58%), 30 (18.40%) and 75 (46.01%) respectively. Using a two test criteria of CRS framed, a total of 104 patients were considered as confirmed cases. Though specificity of blood culture was 100%, the sensitivity was low with significant detection rate in 1st week of illness. Tube Widal showed a sensitivity of 65.38% and specificity of 89.83% with significant detection rate in 2nd week. Dot blot assay for IgM, IgG and Combined IgM and IgG showed a sensitivity of 71.15%, 65.28% and 51.72% respectively whereas, the specificity was 10.16%, 47.45% and 74.57% respectively with significant detection rate in 2nd and 3rd week of illness. CONCLUSION It can be concluded that though blood culture is still the gold standard, Dot blot assay found to have high sensitivity and good specificity might be a practical alternative test for the rapid diagnosis of typhoid fever if interpreted with care particularly using a composite reference standard. Further, it is reliable, simple to perform and rapid; results being available in 1 hour when compared to 48 hours for blood culture and 18 hours for Tube Widal test.
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Affiliation(s)
- Veena Maheshwari
- Assistant Professor, Department of Microbiology, RKDF MCH and RC , Bhopal, India
| | | | - Vijay Kumar Ramnani
- Professor and Head, Department of Microbiology, L.N. Medical College , Bhopal, India
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Tennant SM, Toema D, Qamar F, Iqbal N, Boyd MA, Marshall JM, Blackwelder WC, Wu Y, Quadri F, Khan A, Aziz F, Ahmad K, Kalam A, Asif E, Qureshi S, Khan E, Zaidi AK, Levine MM. Detection of Typhoidal and Paratyphoidal Salmonella in Blood by Real-time Polymerase Chain Reaction. Clin Infect Dis 2016; 61 Suppl 4:S241-50. [PMID: 26449938 DOI: 10.1093/cid/civ726] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND The gold standard for diagnosis of enteric fever caused by Salmonella Typhi or Salmonella Paratyphi A or B is bone marrow culture. However, because bone marrow aspiration is highly invasive, many hospitals and large health centers perform blood culture instead. As blood culture has several limitations, there is a need for novel typhoid diagnostics with improved sensitivity and more rapid time to detection. METHODS We developed a clyA-based real-time polymerase chain reaction (qPCR) method to detect Salmonella Typhi and Salmonella Paratyphi A simultaneously in blood. The sensitivity and specificity of this probeset was first evaluated in vitro in the laboratory and then in a typhoid-endemic population, in Karachi, Pakistan, and in healthy US volunteers. RESULTS We optimized a DNA extraction and real-time PCR-based method that could reliably detect 1 colony-forming unit/mL of Salmonella Typhi. The probe set was able to detect clinical Salmonella Typhi and Salmonella Paratyphi A strains and also diarrheagenic Escherichia coli, but not invasive E. coli or other invasive bacteria. In the field, the clyA qPCR diagnostic was 40% as sensitive as blood culture. However, when qPCR-positive specimens were considered to be true positives, blood culture only exhibited 28.57% sensitivity. Specificity was ≥90% for all comparisons and in the healthy US volunteers. qPCR was significantly faster than blood culture in terms of detection of typhoid and paratyphoid. CONCLUSIONS Based on lessons learned, we recommend that future field trials of this and other novel diagnostics that detect typhoidal and nontyphoidal Salmonella employ multiple methodologies to define a "positive" sample.
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Affiliation(s)
- Sharon M Tennant
- Center for Vaccine Development Department of Medicine, University of Maryland, Baltimore
| | - Deanna Toema
- Center for Vaccine Development Department of Medicine, University of Maryland, Baltimore
| | | | - Najeeha Iqbal
- Department of Paediatrics and Child Health Department of Biological and Biomedical Sciences, Aga Khan University, Karachi, Pakistan
| | - Mary Adetinuke Boyd
- Center for Vaccine Development Department of Pediatrics, University of Maryland, Baltimore
| | - Joanna M Marshall
- Center for Vaccine Development Department of Medicine, University of Maryland, Baltimore
| | - William C Blackwelder
- Center for Vaccine Development Department of Medicine, University of Maryland, Baltimore
| | - Yukun Wu
- Center for Vaccine Development Department of Medicine, University of Maryland, Baltimore
| | | | - Asia Khan
- Department of Paediatrics and Child Health
| | | | | | - Adil Kalam
- Department of Paediatrics and Child Health
| | | | | | - Erum Khan
- Department of Pathology and Microbiology, Aga Khan University, Karachi, Pakistan
| | | | - Myron M Levine
- Center for Vaccine Development Department of Medicine, University of Maryland, Baltimore Department of Pediatrics, University of Maryland, Baltimore
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Storey HL, Huang Y, Crudder C, Golden A, de los Santos T, Hawkins K. A Meta-Analysis of Typhoid Diagnostic Accuracy Studies: A Recommendation to Adopt a Standardized Composite Reference. PLoS One 2015; 10:e0142364. [PMID: 26566275 PMCID: PMC4643909 DOI: 10.1371/journal.pone.0142364] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2015] [Accepted: 10/21/2015] [Indexed: 01/09/2023] Open
Abstract
Novel typhoid diagnostics currently under development have the potential to improve clinical care, surveillance, and the disease burden estimates that support vaccine introduction. Blood culture is most often used as the reference method to evaluate the accuracy of new typhoid tests; however, it is recognized to be an imperfect gold standard. If no single gold standard test exists, use of a composite reference standard (CRS) can improve estimation of diagnostic accuracy. Numerous studies have used a CRS to evaluate new typhoid diagnostics; however, there is no consensus on an appropriate CRS. In order to evaluate existing tests for use as a reference test or inclusion in a CRS, we performed a systematic review of the typhoid literature to include all index/reference test combinations observed. We described the landscape of comparisons performed, showed results of a meta-analysis on the accuracy of the more common combinations, and evaluated sources of variability based on study quality. This wide-ranging meta-analysis suggests that no single test has sufficiently good performance but some existing diagnostics may be useful as part of a CRS. Additionally, based on findings from the meta-analysis and a constructed numerical example demonstrating the use of CRS, we proposed necessary criteria and potential components of a typhoid CRS to guide future recommendations. Agreement and adoption by all investigators of a standardized CRS is requisite, and would improve comparison of new diagnostics across independent studies, leading to the identification of a better reference test and improved confidence in prevalence estimates.
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Affiliation(s)
- Helen L. Storey
- Diagnostics Program, PATH, Seattle, Washington, United States of America
- * E-mail:
| | - Ying Huang
- Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
| | - Chris Crudder
- Diagnostics Program, PATH, Seattle, Washington, United States of America
| | - Allison Golden
- Diagnostics Program, PATH, Seattle, Washington, United States of America
| | - Tala de los Santos
- Diagnostics Program, PATH, Seattle, Washington, United States of America
| | - Kenneth Hawkins
- Diagnostics Program, PATH, Seattle, Washington, United States of America
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Abstract
Salmonella enterica is a leading cause of community-acquired bloodstream infection in Africa. The contribution of typhoidal and nontyphoidal Salmonella serovars to invasive disease varies considerably in place and time, even within the same country. Nonetheless, many African countries are now thought to experience typhoid fever incidence >100 per 100,000 per year with approximately 1% of patients dying. Invasive nontyphoidal Salmonella (iNTS) disease was estimated to cause 3.4 million illnesses and 681 316 deaths in 2010, with the most disease in Africa. Antimicrobial drug resistance is a growing problem in S. enterica that threatens to further compromise patient outcomes. Reservoirs for nontyphoidal Salmonella and the predominant routes of transmission for typhoidal and nontyphoidal Salmonella are not well understood in Africa, hampering the design of evidence-based, non-vaccine- and vaccine-based prevention measures. It is difficult to distinguish clinically invasive Salmonella disease from febrile illnesses caused by other pathogens. Blood cultures are the mainstay of laboratory diagnosis, but lack sensitivity due to the low magnitude of bacteremia, do not produce results at point of care, and are not widely available in Africa. Serologic approaches to diagnosis remain inaccurate, and nucleic acid amplification tests are also compromised by low concentrations of bacteria. High-throughput whole-genome sequencing, together with a range of novel analytic pipelines, has provided new insights into the complex pattern of epidemiology, pathogenesis, and host adaptation. Concerted efforts are therefore needed to apply these new tools in the context of high-quality field surveillance to improve diagnosis, patient management, control, and prevention of invasive Salmonella infections in Africa.
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Affiliation(s)
- John A. Crump
- Centre for International Health, University of Otago, Dunedin, New Zealand
| | - Robert S. Heyderman
- Division of Infection and Immunity, Faculty of Medical Sciences, University College London, United Kingdom
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, University of Malawi College of Medicine, Blantyre
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Development of a TaqMan Array Card for Acute-Febrile-Illness Outbreak Investigation and Surveillance of Emerging Pathogens, Including Ebola Virus. J Clin Microbiol 2015; 54:49-58. [PMID: 26491176 DOI: 10.1128/jcm.02257-15] [Citation(s) in RCA: 69] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2015] [Accepted: 09/28/2015] [Indexed: 12/20/2022] Open
Abstract
Acute febrile illness (AFI) is associated with substantial morbidity and mortality worldwide, yet an etiologic agent is often not identified. Convalescent-phase serology is impractical, blood culture is slow, and many pathogens are fastidious or impossible to cultivate. We developed a real-time PCR-based TaqMan array card (TAC) that can test six to eight samples within 2.5 h from sample to results and can simultaneously detect 26 AFI-associated organisms, including 15 viruses (chikungunya, Crimean-Congo hemorrhagic fever [CCHF] virus, dengue, Ebola virus, Bundibugyo virus, Sudan virus, hantaviruses [Hantaan and Seoul], hepatitis E, Marburg, Nipah virus, o'nyong-nyong virus, Rift Valley fever virus, West Nile virus, and yellow fever virus), 8 bacteria (Bartonella spp., Brucella spp., Coxiella burnetii, Leptospira spp., Rickettsia spp., Salmonella enterica and Salmonella enterica serovar Typhi, and Yersinia pestis), and 3 protozoa (Leishmania spp., Plasmodium spp., and Trypanosoma brucei). Two extrinsic controls (phocine herpesvirus 1 and bacteriophage MS2) were included to ensure extraction and amplification efficiency. Analytical validation was performed on spiked specimens for linearity, intra-assay precision, interassay precision, limit of detection, and specificity. The performance of the card on clinical specimens was evaluated with 1,050 blood samples by comparison to the individual real-time PCR assays, and the TAC exhibited an overall 88% (278/315; 95% confidence interval [CI], 84% to 92%) sensitivity and a 99% (5,261/5,326, 98% to 99%) specificity. This TaqMan array card can be used in field settings as a rapid screen for outbreak investigation or for the surveillance of pathogens, including Ebola virus.
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Crump JA, Sjölund-Karlsson M, Gordon MA, Parry CM. Epidemiology, Clinical Presentation, Laboratory Diagnosis, Antimicrobial Resistance, and Antimicrobial Management of Invasive Salmonella Infections. Clin Microbiol Rev 2015; 28:901-37. [PMID: 26180063 PMCID: PMC4503790 DOI: 10.1128/cmr.00002-15] [Citation(s) in RCA: 651] [Impact Index Per Article: 72.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Salmonella enterica infections are common causes of bloodstream infection in low-resource areas, where they may be difficult to distinguish from other febrile illnesses and may be associated with a high case fatality ratio. Microbiologic culture of blood or bone marrow remains the mainstay of laboratory diagnosis. Antimicrobial resistance has emerged in Salmonella enterica, initially to the traditional first-line drugs chloramphenicol, ampicillin, and trimethoprim-sulfamethoxazole. Decreased fluoroquinolone susceptibility and then fluoroquinolone resistance have developed in association with chromosomal mutations in the quinolone resistance-determining region of genes encoding DNA gyrase and topoisomerase IV and also by plasmid-mediated resistance mechanisms. Resistance to extended-spectrum cephalosporins has occurred more often in nontyphoidal than in typhoidal Salmonella strains. Azithromycin is effective for the management of uncomplicated typhoid fever and may serve as an alternative oral drug in areas where fluoroquinolone resistance is common. In 2013, CLSI lowered the ciprofloxacin susceptibility breakpoints to account for accumulating clinical, microbiologic, and pharmacokinetic-pharmacodynamic data suggesting that revision was needed for contemporary invasive Salmonella infections. Newly established CLSI guidelines for azithromycin and Salmonella enterica serovar Typhi were published in CLSI document M100 in 2015.
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Affiliation(s)
- John A Crump
- Centre for International Health, University of Otago, Dunedin, Otago, New Zealand Division of Foodborne, Waterborne, and Environmental Diseases, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Maria Sjölund-Karlsson
- Division of Foodborne, Waterborne, and Environmental Diseases, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Melita A Gordon
- Department of Clinical Infection, Microbiology and Immunology, Institute of Infection and Global Health, University of Liverpool, Liverpool, United Kingdom Malawi-Liverpool-Wellcome Trust Clinical Research Programme, Blantyre, Malawi
| | - Christopher M Parry
- School of Tropical Medicine and Global Health, Nagasaki University, Nagasaki, Japan Department of Clinical Research, London School of Hygiene and Tropical Medicine, London, United Kingdom Department of Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
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Maude RR, de Jong HK, Wijedoru L, Fukushima M, Ghose A, Samad R, Hossain MA, Karim MR, Faiz MA, Parry CM. The diagnostic accuracy of three rapid diagnostic tests for typhoid fever at Chittagong Medical College Hospital, Chittagong, Bangladesh. Trop Med Int Health 2015; 20:1376-84. [PMID: 26094960 PMCID: PMC4832346 DOI: 10.1111/tmi.12559] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Objective To determine the diagnostic accuracy of three rapid diagnostic tests (RDTs) for typhoid fever in febrile hospitalised patients in Bangladesh. Methods Febrile adults and children admitted to Chittagong Medical College Hospital, Bangladesh, were investigated with Bact/Alert® blood cultures and real‐time PCR to detect Salmonella enterica Typhi and Paratyphi A and assays for Rickettsia, leptospirosis and dengue fever. Acute serum samples were examined with the LifeAssay (LA) Test‐it™ Typhoid IgM lateral flow assay detecting IgM antibodies against S. Typhi O antigen, CTKBiotech Onsite Typhoid IgG/IgM Combo Rapid‐test cassette lateral flow assay detecting IgG and IgM antibodies against S. Typhi O and H antigens and SD Bioline line assay for IgG and IgM antibodies against S. Typhi proteins. Results In 300 malaria smear‐negative febrile patients [median (IQR) age of 13.5 (5–31) years], 34 (11.3%) had confirmed typhoid fever: 19 positive by blood culture for S. Typhi (three blood PCR positive) and 15 blood culture negative but PCR positive for S. Typhi in blood. The respective sensitivity and specificity of the three RDTs in patients using a composite reference standard of blood culture and/or PCR‐confirmed typhoid fever were 59% and 61% for LifeAssay, 59% and 74% for the CTK IgM and/or IgG, and 24% and 96% for the SD Bioline RDT IgM and/or IgG. The LifeAssay RDT had a sensitivity of 63% and a specificity of 91% when modified with a positive cut‐off of ≥2+ and analysed using a Bayesian latent class model. Conclusions These typhoid RDTs demonstrated moderate diagnostic accuracies, and better tests are needed.
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Affiliation(s)
- Rapeephan R Maude
- Mahidol-Oxford Tropical Medicine Research Unit (MORU), Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Hanna K de Jong
- Department of Internal Medicine, Division of Infectious Diseases and Center for Infection and Immunity Amsterdam (CINIMA), Amsterdam, The Netherlands.,Center for Experimental Molecular Medicine (CEMM), Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Lalith Wijedoru
- Mahidol-Oxford Tropical Medicine Research Unit (MORU), Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Masako Fukushima
- Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, UK
| | | | - Rasheda Samad
- Chittagong Medical College Hospital, Chittagong, Bangladesh
| | | | | | - Mohammed Abul Faiz
- Mahidol-Oxford Tropical Medicine Research Unit (MORU), Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.,Centre for Specialized Care and Research, Chittagong, Bangladesh
| | - Christopher M Parry
- Mahidol-Oxford Tropical Medicine Research Unit (MORU), Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.,Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, UK.,London School of Hygiene and Tropical Medicine, London, UK.,School of Tropical Medicine and Global Health, Nagasaki University, Nagasaki, Japan
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Mehmood K, Sundus A, Naqvi IH, Ibrahim MF, Siddique O, Ibrahim NF. Typhidot - A blessing or a menace. Pak J Med Sci 2015; 31:439-43. [PMID: 26101507 PMCID: PMC4476358 DOI: 10.12669/pjms.312.5934] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2014] [Revised: 07/14/2014] [Accepted: 12/15/2014] [Indexed: 11/24/2022] Open
Abstract
Objectives: Typhoid remain an increasing problem in Third world countries like Pakistan. A reliable, easy and affordable rapid diagnostic test is a need for our clinicians, many of whom consider Typhidot to be promising. Typhidot has been used as the only tool to diagnose typhoid fever by general practitioners and consultants despite its low sensitivity and specificity causing misdiagnosis and treatment. We therefore conducted this study to evaluate the sensitivity and specificity of Typhidot in patients with fever. Methods: A retrospective analysis of a total of 145 febrile patients was done. Blood culture and Typhidot along with other relevant investigations had been performed in each case. Sensitivity, specificity and the association of Typhidot to the diagnosis was found using SPSS v16.0. Results: Out of 145 patients, 15(10.3%) had positive blood culture for Salmonella typhi, 7 (4.8%) had positive culture for salmonella paratyphi and 94(64.8%) had positive culture for other organisms. Twenty nine (20%) patients had negative culture results. Forty seven (32.4%) patients had only IgM positive on Typhidot, 7(4.8%) had both IgM and IgG positive and 91(62.8%) had both IgM and IgG negative. Amongst the 130 patients with diseases other than typhoid, 50(38.5%) showed a positive Typhidot result. Amongst the 15 patients with typhoid, 11(73.3%) showed a negative Typhidot result. The sensitivity of Typhidot was found to be 26.7% and the specificity was 61.5%. The Positive Predictive Value (PPV) was 7.4% and the Negative Predictive Value (NPV) was 87.9%. Conclusion: Even though Typhidot is rapid, easy and affordable, its use should be discouraged due to low sensitivity and specificity and insignificant (p=0.067) association to the disease.
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Affiliation(s)
- Khalid Mehmood
- Dr. Khalid Mehmood, FRCP, Head of Department, Medical Unit 3, Civil Hospital Karachi, Pakistan
| | - Ayesha Sundus
- Dr. Ayesha Sundus, MBBS, House Officer, Civil Hospital Karachi, Pakistan
| | - Iftikhar Haider Naqvi
- Dr. Iftikhar Haider Naqvi, FCPS, Assistant Professor, Medical Unit 3, Civil Hospital Karachi, Pakistan
| | - Mohammad Faisal Ibrahim
- Dr. Mohammad Faisal Ibrahim, MBBS, Graduate Medical Student, Dow University of Health Sciences, Karachi, Pakistan
| | - Osama Siddique
- Dr. Osama Siddique, MBBS, Graduate Medical Student, Dow University of Health Sciences, Karachi, Pakistan
| | - Nida Faisal Ibrahim
- Dr. Nida Faisal Ibrahim, MBBS, Graduate Medical Student, Dow University of Health Sciences, Karachi, Pakistan
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Watson CH, Edmunds WJ. A review of typhoid fever transmission dynamic models and economic evaluations of vaccination. Vaccine 2015; 33 Suppl 3:C42-54. [PMID: 25921288 PMCID: PMC4504000 DOI: 10.1016/j.vaccine.2015.04.013] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2015] [Revised: 03/31/2015] [Accepted: 04/01/2015] [Indexed: 01/22/2023]
Abstract
There are relatively few dynamic models or economic analyses of typhoid vaccination. The relative contribution of carriage to transmission is a key uncertainty. Published economic analyses use static models that omit indirect protection of vaccines. Nevertheless, vaccines appear highly cost-effective against WHO criteria in high-incidence settings. No economic model was found to compare vaccine and sanitation.
Despite a recommendation by the World Health Organization (WHO) that typhoid vaccines be considered for the control of endemic disease and outbreaks, programmatic use remains limited. Transmission models and economic evaluation may be informative in decision making about vaccine programme introductions and their role alongside other control measures. A literature search found few typhoid transmission models or economic evaluations relative to analyses of other infectious diseases of similar or lower health burden. Modelling suggests vaccines alone are unlikely to eliminate endemic disease in the short to medium term without measures to reduce transmission from asymptomatic carriage. The single identified data-fitted transmission model of typhoid vaccination suggests vaccines can reduce disease burden substantially when introduced programmatically but that indirect protection depends on the relative contribution of carriage to transmission in a given setting. This is an important source of epidemiological uncertainty, alongside the extent and nature of natural immunity. Economic evaluations suggest that typhoid vaccination can be cost-saving to health services if incidence is extremely high and cost-effective in other high-incidence situations, when compared to WHO norms. Targeting vaccination to the highest incidence age-groups is likely to improve cost-effectiveness substantially. Economic perspective and vaccine costs substantially affect estimates, with disease incidence, case-fatality rates, and vaccine efficacy over time also important determinants of cost-effectiveness and sources of uncertainty. Static economic models may under-estimate benefits of typhoid vaccination by omitting indirect protection. Typhoid fever transmission models currently require per-setting epidemiological parameterisation to inform their use in economic evaluation, which may limit their generalisability. We found no economic evaluation based on transmission dynamic modelling, and no economic evaluation of typhoid vaccination against interventions such as improvements in sanitation or hygiene.
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Affiliation(s)
- Conall H Watson
- Centre for the Mathematical Modelling of Infectious Diseases, London School of Hygiene & Tropical Medicine, United Kingdom.
| | - W John Edmunds
- Centre for the Mathematical Modelling of Infectious Diseases, London School of Hygiene & Tropical Medicine, United Kingdom
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Tarupiwa A, Tapera S, Mtapuri-Zinyowera S, Gumbo P, Ruhanya V, Gudza-Mugabe M, Majuru NX, Chin'ombe N. Evaluation of TUBEX-TF and OnSite Typhoid IgG/IgM Combo rapid tests to detect Salmonella enterica serovar Typhi infection during a typhoid outbreak in Harare, Zimbabwe. BMC Res Notes 2015; 8:50. [PMID: 25890321 PMCID: PMC4344803 DOI: 10.1186/s13104-015-1015-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2014] [Accepted: 02/13/2015] [Indexed: 11/29/2022] Open
Abstract
Background Salmonella enterica serovar Typhi, the causative agent of typhoid, is endemic in most parts of the world especially in Africa. Reliable and rapid diagnosis of the bacterium is therefore critical for confirmation of all suspected typhoid cases. In many parts of Zimbabwe, laboratory capacity to isolate the microorganism by culture method as a way of diagnosis has limitations. In this study, two rapid serological kits, TUBEX-TF and OnSite Typhoid IgG/IgM Combo, were evaluated for possible expeditious diagnosis of Salmonella enterica serovar Typhi infection during a typhoid outbreak in Zimbabwe. Methods Blood was collected from patients with clinical signs and symptoms of typhoid in Harare, Zimbabwe during an outbreak. The standard culture method was used to diagnose the disease. Two rapid kits, the TUBEX-TF and OnSite Typhoid IgG/IgM Combo, were also used in parallel to diagnose typhoid according to manufacturers’ instructions. The diagnostic accuracy of the two kits was evaluated using the culture method as the gold standard. Results From all the cases diagnosed by the blood culture (n = 136), we enrolled 131 patients for the TUBEX-TF and 136 for the OnSite Typhoid IgG/IgM Combo tests. With the culture method as a reference standard, we found that TUBEX-TF test was 100% sensitive and 94.12% specific, with 63.16% positive and 100% negative predictive values (NPVs) and the OnSite Typhoid IgG/IgM Combo test was 100% sensitive and 94.35% specific, with 63.16% positive and 100% NPVs. Conclusion Our results indicated that TUBEX-TF and OnSite Typhoid IgG/IgM Combo rapid tests were useful tools for the rapid diagnosis of Salmonella enterica serovar Typhi infection during typhoid outbreaks in Zimbabwe. The tests performed very well in laboratory evaluations of blood culture-confirmed typhoid cases in Harare, Zimbabwe.
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Affiliation(s)
- Andrew Tarupiwa
- National Microbiology Reference Laboratory, P O Box ST 749, Southerton, Harare, Zimbabwe.
| | - Simba Tapera
- National Microbiology Reference Laboratory, P O Box ST 749, Southerton, Harare, Zimbabwe.
| | | | - Peter Gumbo
- National Microbiology Reference Laboratory, P O Box ST 749, Southerton, Harare, Zimbabwe.
| | - Vurayai Ruhanya
- Department of Medical Microbiology, College of Health Sciences, University of Zimbabwe, P.O. Box A178, Avondale, Zimbabwe.
| | - Muchaneta Gudza-Mugabe
- National Microbiology Reference Laboratory, P O Box ST 749, Southerton, Harare, Zimbabwe.
| | - Ngoni Xmas Majuru
- National Microbiology Reference Laboratory, P O Box ST 749, Southerton, Harare, Zimbabwe.
| | - Nyasha Chin'ombe
- Department of Medical Microbiology, College of Health Sciences, University of Zimbabwe, P.O. Box A178, Avondale, Zimbabwe.
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46
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Jones C, Darton TC, Pollard AJ. Why the development of effective typhoid control measures requires the use of human challenge studies. Front Microbiol 2014; 5:707. [PMID: 25566221 PMCID: PMC4267421 DOI: 10.3389/fmicb.2014.00707] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2014] [Accepted: 11/27/2014] [Indexed: 01/21/2023] Open
Affiliation(s)
- Claire Jones
- Oxford Vaccine Group, Department of Paediatrics, National Institute for Health Research Oxford Biomedical Research Centre, University of Oxford Oxford, UK
| | - Thomas C Darton
- Oxford Vaccine Group, Department of Paediatrics, National Institute for Health Research Oxford Biomedical Research Centre, University of Oxford Oxford, UK
| | - Andrew J Pollard
- Oxford Vaccine Group, Department of Paediatrics, National Institute for Health Research Oxford Biomedical Research Centre, University of Oxford Oxford, UK
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47
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Thompson CN, Kama M, Acharya S, Bera U, Clemens J, Crump JA, Dawainavesi A, Dougan G, Edmunds WJ, Fox K, Jenkins K, Khan MI, Koroivueta J, Levine MM, Martin LB, Nilles E, Pitzer VE, Singh S, Raiwalu RV, Baker S, Mulholland K. Typhoid fever in Fiji: a reversible plague? Trop Med Int Health 2014; 19:1284-92. [PMID: 25066005 PMCID: PMC4285329 DOI: 10.1111/tmi.12367] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The country of Fiji, with a population of approximately 870 000 people, faces a growing burden of several communicable diseases including the bacterial infection typhoid fever. Surveillance data suggest that typhoid has become increasingly common in rural areas of Fiji and is more frequent amongst young adults. Transmission of the organisms that cause typhoid is facilitated by faecal contamination of food or water and may be influenced by local behavioural practices in Fiji. The Fijian Ministry of Health, with support from Australian Aid, hosted a meeting in August 2012 to develop comprehensive control and prevention strategies for typhoid fever in Fiji. International and local specialists were invited to share relevant data and discuss typhoid control options. The resultant recommendations focused on generating a clearer sense of the epidemiology of typhoid in Fiji and exploring the contribution of potential transmission pathways. Additionally, the panel suggested steps such as ensuring that recommended ciprofloxacin doses are appropriate to reduce the potential for relapse and reinfection in clinical cases, encouraging proper hand hygiene of food and drink handlers, working with water and sanitation agencies to review current sanitation practices and considering a vaccination policy targeting epidemiologically relevant populations.
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Affiliation(s)
- Corinne N Thompson
- Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research UnitHo Chi Minh City, Vietnam
- Centre for Tropical Medicine, Nuffield Department of Clinical Medicine, Oxford UniversityOxford, UK
| | | | | | - Una Bera
- Fijian Ministry of HealthSuva, Fiji
| | - John Clemens
- UCLA School of Public HealthLos Angeles, CA, USA
| | - John A Crump
- Centre for International Health, University of OtagoDunedin, New Zealand
| | - Aggie Dawainavesi
- Fijian Ministry of HealthSuva, Fiji
- World Health Organization Division of Pacific Technical SupportSuva, Fiji
| | - Gordon Dougan
- Wellcome Trust Sanger InstituteHinxton, Cambridgeshire, UK
| | - W John Edmunds
- London School of Hygiene and Tropical MedicineLondon, UK
| | - Kimberley Fox
- World Health Organization Regional Office for the Western PacificManila, Philippines
| | | | | | | | - Myron M Levine
- University of Maryland School of MedicineBaltimore, MD, USA
| | - Laura B Martin
- Novartis Vaccines Institute for Global HealthSiena, Italy
| | - Eric Nilles
- World Health Organization Division of Pacific Technical SupportSuva, Fiji
| | | | | | | | - Stephen Baker
- Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research UnitHo Chi Minh City, Vietnam
- Centre for Tropical Medicine, Nuffield Department of Clinical Medicine, Oxford UniversityOxford, UK
- London School of Hygiene and Tropical MedicineLondon, UK
| | - Kim Mulholland
- London School of Hygiene and Tropical MedicineLondon, UK
- Menzies School of Health Research, Royal Darwin Hospital CampusDarwin, NT, Australia
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48
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Dougan G, Baker S. Salmonella entericaSerovar Typhi and the Pathogenesis of Typhoid Fever. Annu Rev Microbiol 2014; 68:317-36. [DOI: 10.1146/annurev-micro-091313-103739] [Citation(s) in RCA: 191] [Impact Index Per Article: 19.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Gordon Dougan
- The Wellcome Trust Sanger Institute, The Wellcome Trust Genome Campus, Hinxton, Cambridge CB10 1SA, United Kingdom;
| | - Stephen Baker
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Program, Oxford University, Clinical Research Unit, Ho Chi Minh City, Vietnam;
- Centre for Tropical Medicine, Oxford University, Oxford OX3 7FZ, United Kingdom
- The London School of Hygiene and Tropical Medicine, London WC1E 7HT, United Kingdom
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49
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Näsström E, Vu Thieu NT, Dongol S, Karkey A, Voong Vinh P, Ha Thanh T, Johansson A, Arjyal A, Thwaites G, Dolecek C, Basnyat B, Baker S, Antti H. Salmonella Typhi and Salmonella Paratyphi A elaborate distinct systemic metabolite signatures during enteric fever. eLife 2014; 3. [PMID: 24902583 PMCID: PMC4077204 DOI: 10.7554/elife.03100] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2014] [Accepted: 05/26/2014] [Indexed: 12/31/2022] Open
Abstract
The host-pathogen interactions induced by Salmonella Typhi and Salmonella Paratyphi A during enteric fever are poorly understood. This knowledge gap, and the human restricted nature of these bacteria, limit our understanding of the disease and impede the development of new diagnostic approaches. To investigate metabolite signals associated with enteric fever we performed two dimensional gas chromatography with time-of-flight mass spectrometry (GCxGC/TOFMS) on plasma from patients with S. Typhi and S. Paratyphi A infections and asymptomatic controls, identifying 695 individual metabolite peaks. Applying supervised pattern recognition, we found highly significant and reproducible metabolite profiles separating S. Typhi cases, S. Paratyphi A cases, and controls, calculating that a combination of six metabolites could accurately define the etiological agent. For the first time we show that reproducible and serovar specific systemic biomarkers can be detected during enteric fever. Our work defines several biologically plausible metabolites that can be used to detect enteric fever, and unlocks the potential of this method in diagnosing other systemic bacterial infections.
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Affiliation(s)
- Elin Näsström
- Department of Chemistry, Computational Life Science Cluster, Umeå University, Umeå, Sweden
| | - Nga Tran Vu Thieu
- Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, The Hospital for Tropical Diseases, Ho Chi Minh City, Vietnam
| | - Sabina Dongol
- Oxford University Clinical Research Unit, Patan Academy of Health Sciences, Kathmandu, Nepal
| | - Abhilasha Karkey
- Oxford University Clinical Research Unit, Patan Academy of Health Sciences, Kathmandu, Nepal
| | - Phat Voong Vinh
- Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, The Hospital for Tropical Diseases, Ho Chi Minh City, Vietnam
| | - Tuyen Ha Thanh
- Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, The Hospital for Tropical Diseases, Ho Chi Minh City, Vietnam
| | - Anders Johansson
- Department of Clinical Microbiology, Umeå University, Umeå, Sweden
| | - Amit Arjyal
- Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, The Hospital for Tropical Diseases, Ho Chi Minh City, Vietnam
| | - Guy Thwaites
- Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, The Hospital for Tropical Diseases, Ho Chi Minh City, Vietnam
| | - Christiane Dolecek
- Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, The Hospital for Tropical Diseases, Ho Chi Minh City, Vietnam
| | - Buddha Basnyat
- Oxford University Clinical Research Unit, Patan Academy of Health Sciences, Kathmandu, Nepal
| | - Stephen Baker
- Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, The Hospital for Tropical Diseases, Ho Chi Minh City, Vietnam
| | - Henrik Antti
- Department of Chemistry, Computational Life Science Cluster, Umeå University, Umeå, Sweden
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50
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Jassim HM, Naushad VA, Alawsi JH, Chandra P, Alkilani H, Wilson G, Matheen M. ASL/ALT ratio as a triage marker for enteric fever in the emergency department. JOURNAL OF EMERGENCY MEDICINE, TRAUMA AND ACUTE CARE 2014. [DOI: 10.5339/jemtac.2014.2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
Objective: Early differentiation of enteric (typhoid) fever from other febrile conditions has been difficult due to the non-specific clinical presentations and lack of substantiating laboratory clues. Transaminase alterations in enteric fever were thought to be non-specific and have not been investigated before in comparison with other febrile conditions with regards to their prevalence and the aspartate amino transferase/alanine amino transferase (AST/ALT) ratio. We sought to examine these parameters as triage markers for enteric fever. Methods: We retrospectively studied 106 patients with enteric fever diagnosed by positive blood culture. 112 febrile patients tested negative for malaria were taken as controls. The controls were matched to the test group with respect to demographic and baseline clinical features. Serum AST, ALT values on first visit to the emergency department was noted and AST/ALT ratio was determined. The values between the test and control groups were compared and the results were analyzed using appropriate statistical methods. Results: The mean AST and ALT levels were found to be significantly higher for enteric fever patients than the control group (109.91 U/L ± 76.07 vs. 29.93 U/L ± 16.74; p < 0.0001) and (83.60 U/L ± 68.04 vs. 32.12 U/L ± 21.79; p < 0.0001) respectively. The mean AST/ALT ratio was found to be higher among enteric fever patients compared to the control group (1.42 ± 0.60 vs.1.07 ± 0.44; p < 0.0001). AST/ALT ratio of ≥ 1 combined with AST of ≥ 40 U/L was found in 72.6% of enteric patients vs. 6.2% in the control group (p < 0.0001). Conclusions: As compared to other common febrile conditions, transaminase alterations in enteric fever seem to follow a specific pattern characterized by higher prevalence of mild elevations (mean levels < 3 fold the upper limit of normal) with a general trend of AST/ALT ratios ≥ 1. In the febrile adult, having an AST/ALT ratio of >1 combined with an AST level of >40 U/L, may provide a simple and cheap triage marker for blood cultures and closer observation especially in the emergency department.
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Affiliation(s)
| | | | | | - Prem Chandra
- 3Medical Research Center, Hamad Medical Corporation, Doha, Qatar
| | - Hani Alkilani
- 2Emergency Department, Al Khor Hospital, Al Khor, Qatar
| | - Gudwin Wilson
- 4Microbiology Section - Laboratory Medicine and Pathology Department, Al Khor Hospital, Qatar
| | - Mubeen Matheen
- 5Biochemistry Section - Laboratory Medicine and Pathology Department, Al Khor Hospital, Qatar
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