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Qureshi S, Maria N, Chawla T, Iqbal J, Kazi AM, Adnan M, Hotwani A, Rahman N, Sadiq MW, Charles R, Baker S, Qamar FN. The frequency and associated factors of typhoid carriage in patients undergoing cholecystectomy for gallbladder disease in Pakistan: A cross-sectional study. PLoS Negl Trop Dis 2024; 18:e0011775. [PMID: 38865361 PMCID: PMC11168639 DOI: 10.1371/journal.pntd.0011775] [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: 11/16/2023] [Accepted: 04/22/2024] [Indexed: 06/14/2024] Open
Abstract
BACKGROUND Enteric fever is caused by Salmonella enterica serovars Typhi (S. Typhi) and Paratyphi A, B, and C. It continues to be a significant cause of morbidity and mortality worldwide. In highly endemic areas, children are disproportionately affected, and antimicrobial resistance reduces therapeutic options. It is estimated that 2-5% of enteric fever patients develop chronic asymptomatic infection. These carriers may act as reservoirs of infection; therefore, the prospective identification and treatment of carriers are critical for long-term disease control. We aimed to find the frequency of Salmonella Typhi carriers in patients undergoing cholecystectomy. We also compared the detection limit of culturing versus qPCR in detecting S. Typhi, performed a geospatial analysis of the carriers identified using this study, and evaluated the accuracy of anti-Vi and anti-YncE in identifying chronic typhoid carriage. METHODS We performed a cross-sectional study in two centers in Pakistan. Gallbladder specimens were subjected to quantitative PCR (qPCR) and serum samples were analyzed for IgG against YncE and Vi by ELISA. We also mapped the residential location of those with a positive qPCR result. FINDINGS Out of 988 participants, 3.4% had qPCR-positive gallbladder samples (23 S. Typhi and 11 S. Paratyphi). Gallstones were more likely to be qPCR positive than bile and gallbladder tissue. Anti-Vi and YncE were significantly correlated (r = 0.78 p<0.0001) and elevated among carriers as compared to qPCR negative controls, except for anti-Vi response in Paratyphi A. But the discriminatory values of these antigens in identifying carriers from qPCR negative controls were low. CONCLUSION The high prevalence of typhoid carriers observed in this study suggests that further studies are required to gain information that will help in controlling future typhoid outbreaks in a superior manner than they are currently being managed.
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Affiliation(s)
- Sonia Qureshi
- Department of Pediatrics and Child Health, Aga Khan University, Karachi, Sindh, Pakistan
| | - Noshi Maria
- Department of Pediatrics and Child Health, Aga Khan University, Karachi, Sindh, Pakistan
| | - Tabish Chawla
- Department of Pediatrics and Child Health, Aga Khan University, Karachi, Sindh, Pakistan
| | - Junaid Iqbal
- Department of Pediatrics and Child Health, Aga Khan University, Karachi, Sindh, Pakistan
| | - Abdul Momin Kazi
- Department of Pediatrics and Child Health, Aga Khan University, Karachi, Sindh, Pakistan
| | - Mehreen Adnan
- Department of Pediatrics and Child Health, Aga Khan University, Karachi, Sindh, Pakistan
| | - Aneeta Hotwani
- Department of Pediatrics and Child Health, Aga Khan University, Karachi, Sindh, Pakistan
| | - Najeeb Rahman
- Department of Pediatrics and Child Health, Aga Khan University, Karachi, Sindh, Pakistan
| | - Muhammed Wahhaab Sadiq
- Department of Pediatrics and Child Health, Aga Khan University, Karachi, Sindh, Pakistan
| | - Richelle Charles
- Division of Infectious Diseases, Massachusetts General Hospital, Boston, Massachusetts, United States of America
- Departments of Medicine and Pediatrics, Harvard Medical School, Boston, Massachusetts, United States of America
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, Massachusetts, United States of America
| | - Stephen Baker
- University of Cambridge School of Clinical Medicine, Cambridge Biomedical Campus, Cambridge, United Kingdom
- Department of Medicine, University of Cambridge School of Clinical Medicine, Cambridge Biomedical Campus, Cambridge, United Kingdom
| | - Farah Naz Qamar
- Department of Pediatrics and Child Health, Aga Khan University, Karachi, Sindh, Pakistan
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Meiring JE, Khanam F, Basnyat B, Charles RC, Crump JA, Debellut F, Holt KE, Kariuki S, Mugisha E, Neuzil KM, Parry CM, Pitzer VE, Pollard AJ, Qadri F, Gordon MA. Typhoid fever. Nat Rev Dis Primers 2023; 9:71. [PMID: 38097589 DOI: 10.1038/s41572-023-00480-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 11/06/2023] [Indexed: 12/18/2023]
Abstract
Typhoid fever is an invasive bacterial disease associated with bloodstream infection that causes a high burden of disease in Africa and Asia. Typhoid primarily affects individuals ranging from infants through to young adults. The causative organism, Salmonella enterica subsp. enterica serovar Typhi is transmitted via the faecal-oral route, crossing the intestinal epithelium and disseminating to systemic and intracellular sites, causing an undifferentiated febrile illness. Blood culture remains the practical reference standard for diagnosis of typhoid fever, where culture testing is available, but novel diagnostic modalities are an important priority under investigation. Since 2017, remarkable progress has been made in defining the global burden of both typhoid fever and antimicrobial resistance; in understanding disease pathogenesis and immunological protection through the use of controlled human infection; and in advancing effective vaccination programmes through strategic multipartner collaboration and targeted clinical trials in multiple high-incidence priority settings. This Primer thus offers a timely update of progress and perspective on future priorities for the global scientific community.
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Affiliation(s)
- James E Meiring
- Division of Clinical Medicine, School of Medicine and Population Health, University of Sheffield, Sheffield, UK
- Malawi-Liverpool-Wellcome Programme, Blantyre, Malawi
| | - Farhana Khanam
- International Centre for Diarrhoel Disease Research, Dhaka, Bangladesh
| | - Buddha Basnyat
- Oxford University Clinical Research Unit, Kathmandu, Nepal
| | - Richelle C Charles
- Massachusetts General Hospital, Harvard Medical School, Harvard T.H. Chan School of Public Health, Boston, MA, USA
| | - John A Crump
- Centre for International Health, University of Otago, Dunedin, New Zealand
| | | | - Kathryn E Holt
- Department of Infection Biology, Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, UK
- Department of Infectious Diseases, Central Clinical School, Monash University, Melbourne, Victoria, Australia
| | - Samuel Kariuki
- Centre for Microbiology Research, Kenya Medical Research Institute, Nairobi, Kenya
| | - Emmanuel Mugisha
- Center for Vaccine Innovation and Access, PATH, Seattle, WA, USA
| | - Kathleen M Neuzil
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Christopher M Parry
- Department of Clinical Sciences and Education, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, UK
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Virginia E Pitzer
- Department of Epidemiology of Microbial Diseases and Public Health Modelling Unit, Yale School of Public Health, Yale University, New Haven, CT, USA
| | - Andrew J Pollard
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford, Oxford, UK
- NIHR Oxford Biomedical Research Centre, Oxford, UK
| | - Firdausi Qadri
- International Centre for Diarrhoel Disease Research, Dhaka, Bangladesh
| | - Melita A Gordon
- Malawi-Liverpool-Wellcome Programme, Blantyre, Malawi.
- Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, UK.
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Dudhane RA, Bankar NJ, Shelke YP, Badge AK. The Rise of Non-typhoidal Salmonella Infections in India: Causes, Symptoms, and Prevention. Cureus 2023; 15:e46699. [PMID: 38021876 PMCID: PMC10630329 DOI: 10.7759/cureus.46699] [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] [Received: 09/10/2023] [Accepted: 10/08/2023] [Indexed: 12/01/2023] Open
Abstract
Non-typhoidal Salmonella infections (NTS) are a growing concern in India, posing a significant health risk to the population. These infections are becoming more common at worrisome rates, primarily because of inadequate surveillance. Salmonella non-typhoidal causes severe gastroenteritis and can even cause invasive infections, such as bacteremia, and focal infections, such as meningitis and septic arthritis, and is acquired through contaminated food and water sources. From moderate to severe, the symptoms might vary. Certain serovars exhibit a stronger propensity for specific syndromes, with serious infections more commonly observed in vulnerable populations. Consuming contaminated food, using inadequate sanitation procedures while handling meat from animals slaughtered, and contaminated water supplies are some of the causes of these diseases. Proper food and water treatment, better sanitary facilities, public awareness campaigns, and adherence to food safety laws are all part of prevention measures. The issue of antimicrobial resistance further emphasizes the necessity for prudent antibiotic usage. The Indian government has put in place programs including public awareness campaigns, better sanitary facilities, and stricter food safety laws. In the future, efforts should, however, concentrate on improving laws, boosting hygienic practices, and funding the development of new medicines and vaccines. These actions will lessen the burden of NTS infections in India by assisting in their prevention and management. This review aims to understand the reasons for this growing tendency, which is essential for creating efficient control and prevention strategies.
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Affiliation(s)
- Radhika A Dudhane
- Microbiology, Datta Meghe Medical College, Datta Meghe Institute of Higher Education and Research, Wardha, IND
| | - Nandkishor J Bankar
- Microbiology, Jawaharlal Nehru Medical College, Datta Meghe Institute of Higher Education and Research, Wardha, IND
| | - Yogendra P Shelke
- Microbiology, Bhaktshreshtha Kamalakarpant Laxmanrao Walwalkar Rural Medical College, Ratnagiri, IND
| | - Ankit K Badge
- Microbiology, Datta Meghe Medical College, Datta Meghe Institute of Higher Education and Research, Wardha, IND
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Johnston PI, Bogue P, Chirambo AC, Mbewe M, Prakash R, Kandoole-Kabwere V, Lester R, Darton T, Baker S, Gordon MA, Meiring JE. Bacterial shedding and serologic responses following an outbreak of Salmonella Typhi in an endemic cohort. BMC Infect Dis 2023; 23:416. [PMID: 37340341 DOI: 10.1186/s12879-023-08385-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2022] [Accepted: 06/08/2023] [Indexed: 06/22/2023] Open
Abstract
BACKGROUND Salmonella enterica serovar Typhi (Salmonella Typhi) is the cause of typhoid fever. Salmonella Typhi may be transmitted through shedding in the stool, which can continue after recovery from acute illness. Shedding is detected by culturing stool, which is challenging to co-ordinate at scale. We hypothesised that sero-surveillance would direct us to those shedding Salmonella Typhi in stool following a typhoid outbreak. METHODS In 2016 a typhoid outbreak affected one in four residents of a Nursing School in Malosa, Malawi. The Department of Health asked for assistance to identify nursing students that might spread the outbreak to other health facilities. We measured IgG antibody titres against Vi capsular polysaccharide (anti-Vi IgG) and IgM / IgG antibodies against H:d flagellin (anti-H:d) three and six months after the outbreak. We selected participants in the highest and lowest deciles for anti-Vi IgG titre (measured at visit one) and obtained stool for Salmonella culture and PCR. All participants reported whether they had experienced fever persisting for three days or more during the outbreak (in keeping with the WHO definitions of 'suspected typhoid'). We tested for salmonellae in the Nursing School environment. RESULTS We obtained 320 paired serum samples from 407 residents. We cultured stool from 25 residents with high anti-Vi IgG titres and 24 residents with low titres. We did not recover Salmonella Typhi from stool; four stool samples yielded non-typhoidal salmonellae; one sample produced a positive PCR amplification for a Salmonella Typhi target. Median anti-Vi and anti-H:d IgG titres fell among participants who reported persistent fever. There was a smaller fall in anti-H:d IgG titres among participants who did not report persistent fever. Non-typhoidal salmonellae were identified in water sampled at source and from a kitchen tap. CONCLUSION High titres of anti-Vi IgG did not identify culture-confirmed shedding of Salmonella Typhi. There was a clear serologic signal of recent typhoid exposure in the cohort, represented by waning IgG antibody titres over time. The presence of non-typhoidal salmonellae in drinking water indicates sub-optimal sanitation. Developing methods to detect and treat shedding remains an important priority to complement typhoid conjugate vaccination in efforts to achieve typhoid elimination.
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Affiliation(s)
- Peter I Johnston
- Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, UK.
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, Blantyre, Malawi.
| | - Patrick Bogue
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, Blantyre, Malawi
| | - Angeziwa Chunga Chirambo
- Department of Medical Laboratory Sciences, Kamuzu University of Health Sciences, Blantyre, Malawi
| | - Maurice Mbewe
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, Blantyre, Malawi
| | - Reenesh Prakash
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, Blantyre, Malawi
| | | | - Rebecca Lester
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, Blantyre, Malawi
| | - Thomas Darton
- Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield, South Yorkshire, UK
| | - Stephen Baker
- Cambridge Institute of Therapeutic Immunology and Infectious Disease, University of Cambridge, Cambridge, UK
| | - Melita A Gordon
- Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, UK
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, Blantyre, Malawi
| | - James E Meiring
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, Blantyre, Malawi
- Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield, South Yorkshire, UK
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McCann N, Scott P, Parry CM, Brown M. Antimicrobial agents for the treatment of enteric fever chronic carriage: A systematic review. PLoS One 2022; 17:e0272043. [PMID: 35905082 PMCID: PMC9337697 DOI: 10.1371/journal.pone.0272043] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Accepted: 07/13/2022] [Indexed: 11/18/2022] Open
Abstract
Background
Chronic carriage of S. Typhi or S. Paratyphi is an important source of enteric fever transmission. Existing guidance and treatment options for this condition are limited. This systematic review aims to assess the evidence concerning the efficacy of different antimicrobials in treating enteric fever chronic carriage.
Methods
We searched major bibliographic databases using relevant keywords between 1946 and September 2021. We included all interventional studies that included patients with confirmed enteric fever chronic carriage and deployed an antimicrobial that remains in clinical practice today. Case reports and case series of under 10 patients were excluded. Two reviewers screened abstracts, selected articles for final inclusion and quality-assessed the included studies for risk of bias. Extracted data was analysed, with pooling of data and eradication rates for each antimicrobial calculated. As only one randomised controlled trial was identified, no meta-analysis was performed.
Results
Of the 593 papers identified by the initial search, a total of eight studies met the inclusion criteria and were included in the systematic review. Evidence was identified for the use of fluoroquinolones and amoxicillin/ampicillin in the treatment for enteric fever chronic carriage. Fluoroquinolones were superior to amoxicillin/ampicillin with 92% of patients achieving eradication after one antimicrobial course compared to 68% (p = 0.02). The quality of included studies was poor, and all were carried out before 1990.
Conclusion
This review identified fluoroquinolones and amoxicillin/ampicillin as treatment options for enteric fever chronic carriage, with fluoroquinolones the more effective option. However, this evidence pre-dates rises in antimicrobial resistance in enteric fever and therefore the significance of these findings to today’s practice is unclear. Further research is needed to investigate whether these antimicrobials remain appropriate treatment options or whether alternative interventions are more effective.
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Affiliation(s)
- Naina McCann
- UCL Faculty of Population Health Sciences, University College London (UCL), London, United Kingdom
- Hospital for Tropical Diseases, University College London Hospitals NHS Foundation Trust, London, United Kingdom
- * E-mail: ,
| | - Peter Scott
- UCL Faculty of Population Health Sciences, University College London (UCL), London, United Kingdom
- Hospital for Tropical Diseases, University College London Hospitals NHS Foundation Trust, London, United Kingdom
| | - Christopher M. Parry
- Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
- Alder Hey Children’s NHS Foundation Trust, Liverpool, United Kingdom
- Centre for Tropical Medicine and Global Health, University of Oxford, Oxford, United Kingdom
| | - Michael Brown
- Hospital for Tropical Diseases, University College London Hospitals NHS Foundation Trust, London, United Kingdom
- Clinical Research Dept, London School of Hygiene & Tropical Medicine, London, United Kingdom
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Khanam F, Darton TC, Meiring JE, Sarker PK, Biswas PK, Bhuiyan MAI, Rajib NH, Tonks S, Pollard AJ, Clemens JD, Qadri F. Salmonella Typhi stool shedding by enteric fever patients and asymptomatic chronic carriers in an endemic urban setting. J Infect Dis 2021; 224:S759-S763. [PMID: 34586391 PMCID: PMC8687075 DOI: 10.1093/infdis/jiab476] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The burden of Salmonella Typhi shedding in stool and its contribution to transmission in endemic settings is unknown. During passive surveillance S. Typhi shedding was seen during convalescence in 332 bacteremic typhoid patients although none persisted at one-year follow-up. Anti-Vi-IgG titres were measured in age-stratified cohort of serosurveillance participants. Systematic stool sampling of 303 participants with high anti-Vi-IgG titres identified one asymptomatic carrier shedding. These findings suggest ongoing S. Typhi transmission in this setting is more likely to occur from acute convalescent cases although better approaches are needed to identify true chronic carriers in the community to enable typhoid elimination.
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Affiliation(s)
- Farhana Khanam
- icddr,b, (International Centre for Diarrhoeal Disease Research, Bangladesh), Dhaka, Bangladesh.,School of Medical Science, Griffith University, Gold Coast, Australia
| | - Thomas C Darton
- Department of Infection, Immunity and Cardiovascular Disease, and the Florey Institute for Host-Pathogen Interactions, University of Sheffield, Sheffield, UK
| | - James E Meiring
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford, and the NIHR Oxford Biomedical Research Centre, Oxford, UK
| | - Protup Kumer Sarker
- icddr,b, (International Centre for Diarrhoeal Disease Research, Bangladesh), Dhaka, Bangladesh
| | - Prasanta Kumar Biswas
- icddr,b, (International Centre for Diarrhoeal Disease Research, Bangladesh), Dhaka, Bangladesh
| | - Md Amirul Islam Bhuiyan
- icddr,b, (International Centre for Diarrhoeal Disease Research, Bangladesh), Dhaka, Bangladesh
| | - Nazmul Hasan Rajib
- icddr,b, (International Centre for Diarrhoeal Disease Research, Bangladesh), Dhaka, Bangladesh
| | - Susan Tonks
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford, and the NIHR Oxford Biomedical Research Centre, Oxford, UK
| | - Andrew J Pollard
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford, and the NIHR Oxford Biomedical Research Centre, Oxford, UK
| | - John D Clemens
- icddr,b, (International Centre for Diarrhoeal Disease Research, Bangladesh), Dhaka, Bangladesh
| | - Firdausi Qadri
- icddr,b, (International Centre for Diarrhoeal Disease Research, Bangladesh), Dhaka, Bangladesh
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Nucleic Acid-Based Lateral Flow Biosensor for Salmonella Typhi and Salmonella Paratyphi: A Detection in Stool Samples of Suspected Carriers. Diagnostics (Basel) 2021; 11:diagnostics11040700. [PMID: 33919817 PMCID: PMC8070779 DOI: 10.3390/diagnostics11040700] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Revised: 04/11/2021] [Accepted: 04/11/2021] [Indexed: 11/17/2022] Open
Abstract
A multiplex rapid detection system, based on a PCR-lateral flow biosensor (mPCR-LFB) was developed to identify Salmonella Typhi and Salmonella Paratyphi A from suspected carriers. The lower detection limit for S. Typhi and S. Paratyphi A was 0.16 and 0.08 ng DNA equivalent to 10 and 102 CFU/mL, respectively. Lateral flow biosensor was used for visual detection of mPCR amplicons (stgA, SPAint, ompC, internal amplification control) by labeling forward primers with fluorescein-isothiocyanate (FITC), Texas Red, dinitrophenol (DNP) and digoxigenin (DIG) and reverse primers with biotin. Binding of streptavidin-colloidal gold conjugate with the amplicons resulted in formation of a red color dots on the strip after 15-20 min of sample exposure. The nucleic acid lateral flow analysis of the mPCR-LFB was better in sensitivity and more rapid than the conventional agarose gel electrophoresis. Moreover, the mPCR-LFB showed 100% sensitivity and specificity when evaluated with stools spiked with 100 isolates of Salmonella genus and other bacteria. A prospective cohort study on stool samples of 1176 food handlers in outbreak areas (suspected carriers) resulted in 23 (2%) positive for S. Typhi. The developed assay has potential to be used for rapid detection of typhoid carriers in surveillance program.
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Gallbladder carriage generates genetic variation and genome degradation in Salmonella Typhi. PLoS Pathog 2020; 16:e1008998. [PMID: 33085725 PMCID: PMC7605710 DOI: 10.1371/journal.ppat.1008998] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Revised: 11/02/2020] [Accepted: 09/21/2020] [Indexed: 11/19/2022] Open
Abstract
Despite recent advances in typhoid fever control, asymptomatic carriage of Salmonella Typhi in the gallbladder remains poorly understood. Aiming to understand if S. Typhi becomes genetically adapted for long-term colonisation in the gallbladder, we performed whole genome sequencing on a collection of S. Typhi isolated from the gallbladders of typhoid carriers. These sequences were compared to contemporaneously sampled sequences from organisms isolated from the blood of acute patients within the same population. We found that S. Typhi carriage was not restricted to any particular genotype or conformation of antimicrobial resistance genes, but was largely reflective of S. Typhi circulating in the general population. However, gallbladder isolates showed a higher genetic variability than acute isolates, with median pairwise SNP distances of 21 and 13 SNPs (p = 2.8x10-9), respectively. Within gallbladder isolates of the predominant H58 genotype, variation was associated with a higher prevalence of nonsense mutations. Notably, gallbladder isolates displayed a higher frequency of non-synonymous mutations in genes encoding hypothetical proteins, membrane lipoproteins, transport/binding proteins, surface antigens, and carbohydrate degradation. Specifically, we identified several gallbladder-specific non-synonymous mutations involved in LPS synthesis and modification, with some isolates lacking the Vi capsular polysaccharide vaccine target due to the 134Kb deletion of SPI-7. S. Typhi is under strong selective pressure in the human gallbladder, which may be reflected phylogenetically by long terminal branches that may distinguish organisms from chronic and acute infections. Our work shows that selective pressures asserted by the hostile environment of the human gallbladder generate new antigenic variants and raises questions regarding the role of carriage in the epidemiology of typhoid fever. Salmonella Typhi is the bacterium that causes typhoid. Salmonella Typhi is infamous for being able to be carried in the gallbladder, with Typhoid Mary being the best-known example of a typhoid carrier. Despite having new tools for typhoid control, we have made little progress in understanding this disease process. Aiming to understand if Salmonella Typhi is adapted for long-term survival in the gallbladder, we sequenced the genomes of 24 Salmonella Typhi isolated from the gallbladders of typhoid carriers. We compared these genomes to Salmonella Typhi from acute typhoid patients within the same population. The carriage of Salmonella Typhi was not restricted to any specific genotype or resistance to antibiotics, but reflective of the organisms causing acute disease. However, gallbladder isolates had higher genetic variability than acute isolates, with a higher frequency of mutations changing the amino acid sequences of hypothetical proteins, membrane lipoproteins, transport/binding proteins, surface antigens, and carbohydrate degradation. We identified several gallbladder-specific mutations involved in polysaccharide synthesis on the bacterial surface. Our work shows that selective pressures asserted by the hostile environment of the human gallbladder generates genetic variation, which is not observed in acute isolates, raising questions regarding the role of carriage in the epidemiology of typhoid.
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Abstract
In 1993, the International Task Force on Disease Eradication classified the political will for typhoid eradication as "none." Here we revisit the Task Force's assessment in light of developments in typhoid vaccines and increasing antimicrobial resistance in Salmonella Typhi that have served to increase interest in typhoid elimination. Considering the requisite biological and technical factors for elimination, effective interventions exist for typhoid, and humans are the organism's only known reservoir. Improvements in water supply, sanitation, hygiene, and food safety are critical for robust long-term typhoid control, and the recent Strategic Advisory Group of Experts on Immunization recommendation and World Health Organization prequalification should make typhoid conjugate vaccine more accessible and affordable in low-income countries, which will allow the vaccine to offer a critical bridge to quickly reduce burden. While these developments are encouraging, all current typhoid diagnostics are inadequate, having either poor performance characteristics, limited scalability, or both. No clear solution exists, and this should be viewed as a critical challenge to any elimination effort. Moreover, asymptomatic carriers and limited data and surveillance remain major challenges, and countries considering elimination campaigns will need to develop strategies to identify high-risk populations and to monitor progress over time. Finally, policymakers must be realistic in planning, learn from the planning failures of previous elimination and eradication efforts, and expect unforeseeable shocks and setbacks. In the end, if we assume neither unanticipated breakthroughs in typhoid control nor any chaotic shocks, history suggests that we should expect typhoid elimination to take decades.
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Affiliation(s)
- Jeffrey D Stanaway
- Institute for Health Metrics and Evaluation, University of Washington, Seattle, Washington, USA
| | - Phionah L Atuhebwe
- World Health Organization, Regional Office for Africa, Brazzaville, Congo
| | - Stephen P Luby
- Infectious Diseases and Geographic Medicine, Stanford University, Stanford, California, USA
| | - John A Crump
- Centre for International Health, University of Otago, Dunedin, New Zealand
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10
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Zerfu B, Medhin G, Mamo G, Getahun G, Tschopp R, Legesse M. Community-based prevalence of typhoid fever, typhus, brucellosis and malaria among symptomatic individuals in Afar Region, Ethiopia. PLoS Negl Trop Dis 2018; 12:e0006749. [PMID: 30286076 PMCID: PMC6191156 DOI: 10.1371/journal.pntd.0006749] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2018] [Revised: 10/16/2018] [Accepted: 08/11/2018] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND In sub-Saharan Africa, where there is the scarcity of proper diagnostic tools, febrile illness related symptoms are often misdiagnosed as malaria. Information on causative agents of febrile illness related symptoms among pastoral communities in Ethiopia have rarely been described. METHODS In this a community based cross-sectional survey, we assessed the prevalence of typhoid fever, typhus, brucellosis and malaria among individuals with a set of given symptoms in Amibara district, Afar Region, Ethiopia. Blood samples were collected from 650 study participants, and examined by Widal and Weilfelix direct card agglutination test (DCAT) as well as test tube based titration test for Salmonella enterica serotype Typhi (S. Typhi) and Rickettsia infections. Rose Bengal Plate Test (RBPT) and Complement Fixation Test (CFT) were used to screen Brucella infection. Thin and thick blood smears were used to diagnosis malaria. RESULTS Out of 630 sera screened by DCAT, 83 (13.2%) were reactive to H and/or O antigens for S. Typhi infection. Among these, 46 (55.4%) were reactive by the titration test at the cut off value ≥ 1:80. The combined sero-prevalence for S. Typhi by the two tests was 7.3% (46/630). The seroprevalence for Rickettsia infection was 26.2% (165/630) by DCAT and 53.3% (88/165) by the titration test at the cut off value ≥ 1:80. The combined sero-prevalence for Rickettsia infection by the two tests was 14.0% (88/630). The sero-prevalence for Brucella infection was 12.7% (80/630) by RBPT, of which 28/80 (35%) were positive by CFT. The combined sero-prevalence for Brucella infection by the two tests was 4.4% (28/630). Out 650 suspected individuals for malaria, 16 (2.5%) were found positive for P. falciparum infection. CONCLUSION In this study, typhoid fever, typhus, brucellosis and malaria were observed among symptomatic individuals. The study also highlighted that brucellosis cases can be misdiagnosed as malaria or other disease based solely on clinical diagnosis. Therefore, efforts are needed to improve disease awareness and laboratory services for the diagnosis of brucellosis and other zoonotic diseases to identify other causes of febrile illness in this pastoral setting.
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Affiliation(s)
- Biruk Zerfu
- Department of Medical Laboratory Sciences, College of Health Sciences, Addis Ababa University, Addis Ababa, Ethiopia
| | - Girmay Medhin
- Microbiology Research Unit, Aklilu Lemma Institute of Pathobiology, Addis Ababa University, Addis Ababa, Ethiopia
| | - Gezahegne Mamo
- Department of Veterinary Microbiology, Immunology and Public Health, College of Veterinary Medicine and Agriculture, Addis Ababa University, Bishoftu, Ethiopia
| | - Gezahegn Getahun
- Melka Werer Health Center, Amibara district, Melka Were, Ethiopia
| | - Rea Tschopp
- Armauer Hansen Research Institute, Addis Ababa, Ethiopia
- Swiss TPH, Basel, Switzerland
| | - Mengistu Legesse
- Microbiology Research Unit, Aklilu Lemma Institute of Pathobiology, Addis Ababa University, Addis Ababa, Ethiopia
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11
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Näsström E, Jonsson P, Johansson A, Dongol S, Karkey A, Basnyat B, Tran Vu Thieu N, Trinh Van T, Thwaites GE, Antti H, Baker S. Diagnostic metabolite biomarkers of chronic typhoid carriage. PLoS Negl Trop Dis 2018; 12:e0006215. [PMID: 29373578 PMCID: PMC5802941 DOI: 10.1371/journal.pntd.0006215] [Citation(s) in RCA: 19] [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: 10/08/2017] [Revised: 02/07/2018] [Accepted: 01/05/2018] [Indexed: 12/13/2022] Open
Abstract
Background Salmonella Typhi and Salmonella Paratyphi A are the agents of enteric (typhoid) fever; both can establish chronic carriage in the gallbladder. Chronic Salmonella carriers are typically asymptomatic, intermittently shedding bacteria in the feces, and contributing to disease transmission. Detecting chronic carriers is of public health relevance in areas where enteric fever is endemic, but there are no routinely used methods for prospectively identifying those carrying Salmonella in their gallbladder. Methodology/Principal findings Here we aimed to identify biomarkers of Salmonella carriage using metabolite profiling. We performed metabolite profiling on plasma from Nepali patients undergoing cholecystectomy with confirmed S. Typhi or S. Paratyphi A gallbladder carriage (and non-carriage controls) using two-dimensional gas chromatography coupled with time-of-flight mass spectrometry (GCxGC-TOFMS) and supervised pattern recognition modeling. We were able to significantly discriminate Salmonella carriage samples from non-carriage control samples. We were also able to detect differential signatures between S. Typhi and S. Paratyphi A carriers. We additionally compared carriage metabolite profiles with profiles generated during acute infection; these data revealed substantial heterogeneity between metabolites associated with acute enteric fever and chronic carriage. Lastly, we found that Salmonella carriers could be significantly distinguished from non-carriage controls using only five metabolites, indicating the potential of these metabolites as diagnostic markers for detecting chronic Salmonella carriers. Conclusions/Significance Our novel approach has highlighted the potential of using metabolomics to search for diagnostic markers of chronic Salmonella carriage. We suggest further epidemiological investigations of these potential biomarkers in alternative endemic enteric fever settings. Enteric fever, caused by typhoidal Salmonella serovars, remains a substantial public health problem in many low- and middle-income countries. The human-restricted nature of these organisms combined with the development of new vaccines suggests that regional elimination of enteric fever should be possible. However, individuals that chronically carry Salmonella in their gallbladder, such as the notorious Typhoid Mary, complicates enteric fever transmission and maintain circulation of the organisms. The prospective detection of chronic Salmonella carriers is therefore a critical step for regional enteric fever elimination. However, there are currently no diagnostic methods routinely in use for this purpose. Here, we used a novel method for identifying chronic Salmonella carriers by comparing metabolite patterns in plasma samples from patients with chronic Salmonella carriage against non-carriage controls. We could significantly distinguish Salmonella carriers from non-carriers based on a large set of metabolites. Five metabolites were then highlighted, after comparing metabolite patterns obtained during chronic Salmonella carriage and acute enteric fever respectively, which could significantly distinguish Salmonella carriers from non-carriers. These potential biomarkers require further evaluation in epidemiological investigations of enteric fever in alternative endemic settings but this study provides a first step towards improved detection of Salmonella carriers.
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Affiliation(s)
- Elin Näsström
- Department of Chemistry, Umeå University, Umeå, Sweden
| | - Pär Jonsson
- Department of Chemistry, Umeå University, Umeå, Sweden
| | - Anders Johansson
- Department of Clinical Microbiology and the Laboratory for Molecular Infection Medicine Sweden, Umeå University, Umeå, Sweden
| | - 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
| | - Buddha Basnyat
- Oxford University Clinical Research Unit, Patan Academy of Health Sciences, Kathmandu, Nepal
| | - Nga Tran Vu Thieu
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
| | - Tan Trinh Van
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
| | - Guy E. Thwaites
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
- Centre for Tropical Medicine and Global Health, Oxford University, Oxford, United Kingdom
| | - Henrik Antti
- Department of Chemistry, Umeå University, Umeå, Sweden
- * E-mail: (SB); (HA)
| | - Stephen Baker
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
- Centre for Tropical Medicine and Global Health, Oxford University, Oxford, United Kingdom
- The Department of Medicine, The University of Cambridge, Cambridge, United Kingdom
- * E-mail: (SB); (HA)
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12
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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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13
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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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14
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Yap KP, Thong KL. Salmonella Typhi genomics: envisaging the future of typhoid eradication. Trop Med Int Health 2017; 22:918-925. [PMID: 28544285 DOI: 10.1111/tmi.12899] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Next-generation whole-genome sequencing has revolutionised the study of infectious diseases in recent years. The availability of genome sequences and its understanding have transformed the field of molecular microbiology, epidemiology, infection treatments and vaccine developments. We review the key findings of the publicly accessible genomes of Salmonella enterica serovar Typhi since the first complete genome to the most recent release of thousands of Salmonella Typhi genomes, which remarkably shape the genomic research of S. Typhi and other pathogens. Important new insights acquired from the genome sequencing of S. Typhi, pertaining to genomic variations, evolution, population structure, antibiotic resistance, virulence, pathogenesis, disease surveillance/investigation and disease control are discussed. As the numbers of sequenced genomes are increasing at an unprecedented rate, fine variations in the gene pool of S. Typhi are captured in high resolution, allowing deeper understanding of the pathogen's evolutionary trends and its pathogenesis, paving the way to bringing us closer to eradication of typhoid through effective vaccine/treatment development.
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Affiliation(s)
- Kien-Pong Yap
- Institute of Biological Science, Faculty of Science, University of Malaya, Kuala Lumpur, Malaysia
| | - Kwai Lin Thong
- Institute of Biological Science, Faculty of Science, University of Malaya, Kuala Lumpur, Malaysia
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15
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Im J, Nichols C, Bjerregaard-Andersen M, Sow AG, Løfberg S, Tall A, Pak GD, Aaby P, Baker S, Clemens JD, Espinoza LMC, Konings F, May J, Monteiro M, Niang A, Panzner U, Park SE, Schütt-Gerowitt H, Wierzba TF, Marks F, von Kalckreuth V. Prevalence of Salmonella Excretion in Stool: A Community Survey in 2 Sites, Guinea-Bissau and Senegal. Clin Infect Dis 2016; 62 Suppl 1:S50-5. [PMID: 26933022 DOI: 10.1093/cid/civ789] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Chronic and convalescent carriers play an important role in the transmission and endemicity of many communicable diseases. A high incidence of Salmonella enterica serovar Typhi and invasive nontyphoidal Salmonella (NTS) infection has been reported in parts of sub-Saharan Africa, yet the prevalence of Salmonella excretion in the general population is unknown. METHODS Stool specimens were collected from a random sample of households in 2 populations in West Africa: Bissau, Guinea-Bissau, and Dakar, Senegal. Stool was cultured to detect presence of Salmonella, and antimicrobial susceptibility testing was performed on the isolated organisms. RESULTS Stool was cultured from 1077 and 1359 individuals from Guinea-Bissau and Senegal, respectively. Salmonella Typhi was not isolated from stool samples at either site. Prevalence of NTS in stool samples was 24.1 (95% confidence interval [CI], 16.5-35.1; n = 26/1077) per 1000 population in Guinea-Bissau and 10.3 (95% CI, 6.1-17.2; n = 14/1359) per 1000 population in Senegal. CONCLUSIONS Evidence of NTS excretion in stool in both study populations indicates a possible NTS transmission route in these settings.
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Affiliation(s)
- Justin Im
- International Vaccine Institute, Seoul, Republic of Korea
| | | | | | - Amy Gassama Sow
- Institut Pasteur de Dakar Université Cheikh Anta Diop de Dakar, Senegal
| | - Sandra Løfberg
- Bandim Health Project, INDEPTH Network, Bissau, Guinea-Bissau
| | | | - Gi Deok Pak
- International Vaccine Institute, Seoul, Republic of Korea
| | - Peter Aaby
- Bandim Health Project, INDEPTH Network, Bissau, Guinea-Bissau
| | - Stephen Baker
- Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam Centre for Tropical Medicine, Nuffield Department of Clinical Medicine, Oxford University London School of Hygiene and Tropical Medicine, United Kingdom
| | - John D Clemens
- International Vaccine Institute, Seoul, Republic of Korea International Centre for Diarrhoeal Disease Research, Bangladesh (icddr,b), Dhaka Fielding School of Public Health, University of California, Los Angeles
| | | | - Frank Konings
- International Vaccine Institute, Seoul, Republic of Korea
| | - Jürgen May
- Bernhard Nocht Institute for Tropical Medicine, and German Center for Infection Research, partner site Hamburg-Borstel-Lübeck, Hamburg
| | - Mario Monteiro
- Bandim Health Project, INDEPTH Network, Bissau, Guinea-Bissau
| | | | - Ursula Panzner
- International Vaccine Institute, Seoul, Republic of Korea
| | - Se Eun Park
- International Vaccine Institute, Seoul, Republic of Korea
| | - Heidi Schütt-Gerowitt
- International Vaccine Institute, Seoul, Republic of Korea Institute of Medical Microbiology, University of Cologne, Germany
| | | | - Florian Marks
- International Vaccine Institute, Seoul, Republic of Korea
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16
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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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17
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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: 659] [Impact Index Per Article: 73.2] [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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18
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Gunn JS, Marshall JM, Baker S, Dongol S, Charles RC, Ryan ET. Salmonella chronic carriage: epidemiology, diagnosis, and gallbladder persistence. Trends Microbiol 2014; 22:648-55. [PMID: 25065707 PMCID: PMC4252485 DOI: 10.1016/j.tim.2014.06.007] [Citation(s) in RCA: 184] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2014] [Revised: 06/26/2014] [Accepted: 06/27/2014] [Indexed: 12/13/2022]
Abstract
Typhoid (enteric fever) remains a major cause of morbidity and mortality worldwide, causing over 21 million new infections annually, with the majority of deaths occurring in young children. Because typhoid fever-causing Salmonella have no known environmental reservoir, the chronic, asymptomatic carrier state is thought to be a key feature of continued maintenance of the bacterium within human populations. Despite the importance of this disease to public health, our understanding of the molecular mechanisms that catalyze carriage, as well as our ability to reliably identify and treat the Salmonella carrier state, have only recently begun to advance.
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Affiliation(s)
- John S Gunn
- Department of Microbial Infection and Immunity, Center for Microbial Interface Biology, The Ohio State University, OH, USA.
| | - Joanna M Marshall
- Department of Microbial Infection and Immunity, Center for Microbial Interface Biology, The Ohio State University, OH, USA
| | - Stephen Baker
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam; Centre for Tropical Medicine, Oxford University, Oxford, United Kingdom; The London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Sabina Dongol
- Oxford University Clinical Research Unit, Patan Academy of Health Sciences, Kathmandu, Nepal
| | - Richelle C Charles
- Division of Infectious Diseases, Massachusetts General Hospital, Boston, MA, USA; Department of Medicine, Harvard Medical School, Boston, MA, USA
| | - Edward T Ryan
- Division of Infectious Diseases, Massachusetts General Hospital, Boston, MA, USA; Department of Medicine, Harvard Medical School, Boston, MA, USA; Department of Immunology and Infectious Diseases, Harvard School of Public Health, Boston, MA, USA
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19
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Parry CM, Wijedoru L, Arjyal A, Baker S. The utility of diagnostic tests for enteric fever in endemic locations. Expert Rev Anti Infect Ther 2014; 9:711-25. [DOI: 10.1586/eri.11.47] [Citation(s) in RCA: 118] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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20
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Saul A, Smith T, Maire N. Stochastic simulation of endemic Salmonella enterica serovar Typhi: the importance of long lasting immunity and the carrier state. PLoS One 2013; 8:e74097. [PMID: 24040177 PMCID: PMC3769365 DOI: 10.1371/journal.pone.0074097] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2013] [Accepted: 07/28/2013] [Indexed: 11/29/2022] Open
Abstract
Background Typhoid fever caused by Salmonella enterica serovar Typhi (S. Typhi) remains a serious burden of disease, especially in developing countries of Asia and Africa. It is estimated that it causes 200,000 deaths per year, mainly in children. S. Typhi is an obligate pathogen of humans and although it has a relatively complex life cycle with a long lived carrier state, the absence of non-human hosts suggests that well targeted control methods should have a major impact on disease. Newer control methods including new generations of vaccines offer hope but their implementation would benefit from quantitative models to guide the most cost effective strategies. This paper presents a quantitative model of Typhoid disease, immunity and transmission as a first step in that process. Methodology/Principal Findings A stochastic agent-based model has been developed that incorporates known features of the biology of typhoid including probability of infection, the consequences of infection, treatment options, acquisition and loss of immunity as a result of infection and vaccination, the development of the carrier state and the impact of environmental or behavioral factors on transmission. The model has been parameterized with values derived where possible from the literature and where this was not possible, feasible parameters space has been determined by sensitivity analyses, fitting the simulations to age distribution of field data. The model is able to adequately predict the age distribution of typhoid in two settings. Conclusions/Significance The modeling highlights the importance of variations in the exposure/resistance of infants and young children to infection in different settings, especially as this impacts on design of control programs; it predicts that naturally induced clinical and sterile immunity to typhoid is long lived and highlights the importance of the carrier state especially in areas of low transmission.
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Affiliation(s)
- Allan Saul
- Novartis Vaccines Institute for Global Health, Siena, Italy
- * E-mail:
| | - Tom Smith
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - Nicolas Maire
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
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21
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Charles RC, Sultana T, Alam MM, Yu Y, Wu-Freeman Y, Bufano MK, Rollins SM, Tsai L, Harris JB, LaRocque RC, Leung DT, Brooks WA, Nga TVT, Dongol S, Basnyat B, Calderwood SB, Farrar J, Khanam F, Gunn JS, Qadri F, Baker S, Ryan ET. Identification of immunogenic Salmonella enterica serotype Typhi antigens expressed in chronic biliary carriers of S. Typhi in Kathmandu, Nepal. PLoS Negl Trop Dis 2013; 7:e2335. [PMID: 23936575 PMCID: PMC3731212 DOI: 10.1371/journal.pntd.0002335] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2013] [Accepted: 06/12/2013] [Indexed: 11/21/2022] Open
Abstract
Background Salmonella enterica serotype Typhi can colonize and persist in the biliary tract of infected individuals, resulting in a state of asymptomatic chronic carriage. Chronic carriers may act as persistent reservoirs of infection within a community and may introduce infection to susceptible individuals and new communities. Little is known about the interaction between the host and pathogen in the biliary tract of chronic carriers, and there is currently no reliable diagnostic assay to identify asymptomatic S. Typhi carriage. Methodology/Principal Findings To study host-pathogen interactions in the biliary tract during S. Typhi carriage, we applied an immunoscreening technique called in vivo-induced antigen technology (IVIAT), to identify potential biomarkers unique to carriers. IVIAT identifies humorally immunogenic bacterial antigens expressed uniquely in the in vivo environment, and we hypothesized that S. Typhi surviving in the biliary tract of humans may express a distinct antigenic profile. Thirteen S. Typhi antigens that were immunoreactive in carriers, but not in healthy individuals from a typhoid endemic area, were identified. The identified antigens included a number of putative membrane proteins, lipoproteins, and hemolysin-related proteins. YncE (STY1479), an uncharacterized protein with an ATP-binding motif, gave prominent responses in our screen. The response to YncE in patients whose biliary tract contained S. Typhi was compared to responses in patients whose biliary tract did not contain S. Typhi, patients with acute typhoid fever, and healthy controls residing in a typhoid endemic area. Seven of 10 (70%) chronic carriers, 0 of 8 bile culture-negative controls (0%), 0 of 8 healthy Bangladeshis (0%), and 1 of 8 (12.5%) Bangladeshis with acute typhoid fever had detectable anti-YncE IgG in blood. IgA responses were also present. Conclusions/Significance Further evaluation of YncE and other antigens identified by IVIAT could lead to the development of improved diagnostic assays to identify asymptomatic S. Typhi carriers. Salmonella enterica serotype Typhi is the cause of typhoid fever and infects over 21 million individuals and causes 200,000 deaths each year. With adequate treatment, most patients recover from their acute stage of illness and clear infection. However, a small percentage of S. Typhi infected individuals develop a chronic but asymptomatic infection in the biliary tract that can persist for decades. Since S. Typhi is a human-restricted pathogen, chronic carriers may act as reservoirs of infection. Correctly identifying and treating asymptomatic chronic carriers could be critical for ultimate control of typhoid fever. Using an immunoscreening technique called in vivo-induced antigen technology (IVIAT), we have identified potential biomarkers unique to S. Typhi chronic carriers. Further evaluation of these antigens could lead to the development of improved diagnostic assays to detect asymptomatic S. Typhi carriers in typhoid endemic zones, and to an improved understanding of the pathogenesis of S. Typhi in the chronic carrier state.
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Affiliation(s)
- Richelle C Charles
- Division of Infectious Diseases, Massachusetts General Hospital, Boston, Massachusetts, USA.
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22
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Guerra-Silveira F, Abad-Franch F. Sex bias in infectious disease epidemiology: patterns and processes. PLoS One 2013; 8:e62390. [PMID: 23638062 PMCID: PMC3634762 DOI: 10.1371/journal.pone.0062390] [Citation(s) in RCA: 197] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2012] [Accepted: 03/25/2013] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND Infectious disease incidence is often male-biased. Two main hypotheses have been proposed to explain this observation. The physiological hypothesis (PH) emphasizes differences in sex hormones and genetic architecture, while the behavioral hypothesis (BH) stresses gender-related differences in exposure. Surprisingly, the population-level predictions of these hypotheses are yet to be thoroughly tested in humans. METHODS AND FINDINGS For ten major pathogens, we tested PH and BH predictions about incidence and exposure-prevalence patterns. Compulsory-notification records (Brazil, 2006-2009) were used to estimate age-stratified ♂:♀ incidence rate ratios for the general population and across selected sociological contrasts. Exposure-prevalence odds ratios were derived from 82 published surveys. We estimated summary effect-size measures using random-effects models; our analyses encompass ∼0.5 million cases of disease or exposure. We found that, after puberty, disease incidence is male-biased in cutaneous and visceral leishmaniasis, schistosomiasis, pulmonary tuberculosis, leptospirosis, meningococcal meningitis, and hepatitis A. Severe dengue is female-biased, and no clear pattern is evident for typhoid fever. In leprosy, milder tuberculoid forms are female-biased, whereas more severe lepromatous forms are male-biased. For most diseases, male bias emerges also during infancy, when behavior is unbiased but sex steroid levels transiently rise. Behavioral factors likely modulate male-female differences in some diseases (the leishmaniases, tuberculosis, leptospirosis, or schistosomiasis) and age classes; however, average exposure-prevalence is significantly sex-biased only for Schistosoma and Leptospira. CONCLUSIONS Our results closely match some key PH predictions and contradict some crucial BH predictions, suggesting that gender-specific behavior plays an overall secondary role in generating sex bias. Physiological differences, including the crosstalk between sex hormones and immune effectors, thus emerge as the main candidate drivers of gender differences in infectious disease susceptibility.
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Affiliation(s)
- Felipe Guerra-Silveira
- Instituto Leônidas e Maria Deane – Fiocruz Amazônia, Manaus, Amazonas, Brazil
- School of Medicine, Universidade do Estado do Amazonas, Manaus, Amazonas, Brazil
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23
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A human IgG anti-Vi reference for Salmonella typhi with weight-based antibody units assigned. Vaccine 2013; 31:1970-4. [PMID: 23422143 DOI: 10.1016/j.vaccine.2013.02.006] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2012] [Revised: 01/08/2013] [Accepted: 02/04/2013] [Indexed: 11/22/2022]
Abstract
Recent data showing the high incidence of typhoid fever in young children, the demonstration of safety and efficacy of a Vi conjugate for this age group, the safety and similar immunogenicity in infants when administrated concurrently with EPI vaccines, together with the interests of manufacturers and investigators in studying such conjugate vaccines prompted us to prepare a human IgG anti-Vi standard to facilitate this work. Volunteers were injected with an investigational Vi-recombinant Pseudomonas aeruginosa exoprotein A (Vi-rEPA) conjugate vaccine. Plasmas with the highest levels of IgG anti-Vi were pooled. The IgG anti-Vi content of this preparation, assayed by precipitin analysis with purified Vi, was 33 μg/ml. Accordingly, the estimated IgG anti-Vi protective level of 3.5 ELISA unit/ml, derived from our efficacy trial of Vi-rEPA in 2-5 years old children, is equivalent to 4.3 μg/ml. This reagent is suitable for comparison of immune response of Vi conjugate vaccines or for other purposes requiring anti-Vi measurement.
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24
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Baddam R, Kumar N, Shaik S, Suma T, Ngoi ST, Thong KL, Ahmed N. Genome sequencing and analysis of Salmonella enterica serovar Typhi strain CR0063 representing a carrier individual during an outbreak of typhoid fever in Kelantan, Malaysia. Gut Pathog 2012; 4:20. [PMID: 23234298 PMCID: PMC3528463 DOI: 10.1186/1757-4749-4-20] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/14/2012] [Accepted: 11/29/2012] [Indexed: 12/01/2022] Open
Abstract
Salmonella Typhi is a human restricted pathogen with a significant number of individuals as asymptomatic carriers of the bacterium. Salmonella infection can be effectively controlled if a reliable method for identification of these carriers is developed. In this context, the availability of whole genomes of carrier strains through high- throughput sequencing and further downstream analysis by comparative genomics approaches is very promising. Herein we describe the genome sequence of a Salmonella Typhi isolate representing an asymptomatic carrier individual during a prolonged outbreak of typhoid fever in Kelantan, Malaysia. Putative genomic coordinates relevant in pathogenesis and persistence of this carrier strain are identified and discussed.
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Affiliation(s)
- Ramani Baddam
- Pathogen Biology Laboratory, Department of Biotechnology and Bioinformatics, School of Life Sciences, University of Hyderabad, Hyderabad, India.
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25
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Chua AL, Aziah I, Balaram P, Bhuvanendran S, Anthony AA, Mohmad SN, Nasir NM, Hassan H, Naim R, Meran LP, Hussin HM, Ismail A. Identification of carriers among individuals recruited in the typhoid registry in Malaysia using stool culture, polymerase chain reaction, and dot enzyme immunoassay as detection tools. Asia Pac J Public Health 2012; 27:NP2740-8. [PMID: 23000800 DOI: 10.1177/1010539512458521] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Chronic carriers of Salmonella Typhi act as reservoirs for the organism and become the agents of typhoid outbreaks in a community. In this study, chronic carriers in Kelantan, Malaysia were first identified using the culture and polymerase chain reaction method. Then, a novel serological tool, designated Typhidot-C, was evaluated in retrospect using the detected individuals as control positives. Chronic carriage positive by the culture and polymerase chain reaction method was recorded at 3.6% (4 out of 110) among individuals who previously had acute typhoid fever and a 9.4% (10 out of 106) carriage rate was observed among food handlers screened during outbreaks. The Typhidot-C assay was able to detect all these positive carriers showing its potential as a viable carrier screening tool and can be used for efficient detection of typhoid carriers in an endemic area. These findings were used to establish the first carrier registry for S Typhi carriers in Malaysia.
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Affiliation(s)
- Ang Lim Chua
- Universiti Sains Malaysia, Kubang Kerian, Malaysia
| | - Ismail Aziah
- Universiti Sains Malaysia, Kubang Kerian, Malaysia
| | | | | | | | | | | | | | - Rochman Naim
- Universiti Sains Malaysia, Kubang Kerian, Malaysia
| | | | | | - Asma Ismail
- Universiti Sains Malaysia, Kubang Kerian, Malaysia
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26
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Gopinath S, Carden S, Monack D. Shedding light on Salmonella carriers. Trends Microbiol 2012; 20:320-7. [DOI: 10.1016/j.tim.2012.04.004] [Citation(s) in RCA: 100] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2012] [Revised: 04/03/2012] [Accepted: 04/10/2012] [Indexed: 01/10/2023]
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27
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Bhuvanendran S, Hussin HM, Meran LP, Anthony AA, Zhang L, Burch LH, Phua KK, Ismail A, Balaram P. Toll-like receptor 4 Asp299Gly and Thr399Ile polymorphisms and typhoid susceptibility in Asian Malay population in Malaysia. Microbes Infect 2011; 13:844-51. [PMID: 21612766 DOI: 10.1016/j.micinf.2011.04.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2011] [Revised: 04/10/2011] [Accepted: 04/18/2011] [Indexed: 12/19/2022]
Abstract
Typhoid fever is a major health problem with frequent outbreaks in Kelantan, Malaysia. Prevalence of TLR4 gene polymorphisms varies with ethnic groups (0-20%) and predisposean individual to gram-negative infections. The prevalence rate of TLR4 Asp299Gly and Thr399lle polymorphisms in the Malay population or the influence of these on typhoid fever susceptibility is not yet reported. 250 normal and 304 susceptible Malay individuals were investigated for these polymorphisms using allele-specific PCR and analysed for its association with typhoid fever susceptibility. The total prevalence of polymorphisms in the normal population was 4.8% in comparison to 12.5% in the susceptible population (p = 0.002). An increased frequency of both polymorphisms was observed in the susceptible population (p < 0.01) with no homozygous mutants observed. Co-segregation was observed in 2% of controls and 3.6% of the susceptible individuals. This study, for the first time, reports the prevalence of TLR4 gene polymorphisms in the Malay population and suggests that these polymorphisms confer a higher risk for typhoid, infection. The higher incidence of typhoid fever in Kelantan could be attributed to the higher percentage of Malays (95%) in this state. In order to reduce the incidence of this disease, people with these polymorphisms, can be prioritised for prophylactic strategies.
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Affiliation(s)
- Saatheeyavaane Bhuvanendran
- Institute for Research in Molecular Medicine, Health Campus, Universiti Sains Malaysia, 16150 Kubang Kerian, Kelantan, Malaysia
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28
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Safaeian M, Gao YT, Sakoda LC, Quraishi SM, Rashid A, Wang BS, Chen J, Pruckler J, Mintz E, Hsing AW. Chronic typhoid infection and the risk of biliary tract cancer and stones in Shanghai, China. Infect Agent Cancer 2011; 6:6. [PMID: 21535882 PMCID: PMC3110129 DOI: 10.1186/1750-9378-6-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2010] [Accepted: 05/02/2011] [Indexed: 01/06/2023] Open
Abstract
Previous studies have shown a positive association between chronic typhoid carriage and biliary cancers. We compared serum Salmonella enterica serovar Typhi antibody titers between biliary tract cancer cases, biliary stone cases without evidence of cancer, and healthy subjects in a large population-based case-control study in Shanghai, China. Participants included 627 newly diagnosed primary biliary tract cancer patients; 1,037 biliary stone cases (774 gallbladder and 263 bile-duct) and 959 healthy subjects without a history of cancer, randomly selected from the Shanghai Resident Registry. Overall only 6/2,293 (0.26%) were Typhi positive. The prevalence of Typhi was 1/457 (0.22%), 4/977 (0.41%), and 1/859 (0.12%) among cancer cases, biliary-stone cases, and population controls, respectively. We did not find an association between Typhi and biliary cancer in Shanghai, due to the very low prevalence of chronic carriers in this population. The low seroprevalence of S. Typhi in Shanghai is unlikely to explain the high incidence of biliary cancers in this population.
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Affiliation(s)
- Mahboobeh Safaeian
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, Bethesda, Maryland, USA.
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29
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An outbreak of Salmonella Paratyphi A in a boarding school: a community-acquired enteric fever and carriage investigation. Epidemiol Infect 2010; 138:1765-74. [PMID: 20800009 DOI: 10.1017/s0950268810001986] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Salmonella Paratyphi A (SPA) is rapidly becoming a common cause of enteric fever in South East Asia. A large outbreak of SPA occurred in a boarding middle school in China in 2004. There were 394 suspected cases; 95·5% were students. The highest incidence was in the youngest children (7th grade). Forty-four of 151 (29%) blood cultures and 4/54 (7·4%) rectal swabs were positive for SPA; three were from kitchen workers. The geometric mean levels of serum IgG anti-lipopolysaccharide (anti-LPS) from patients was higher than from healthy individuals [35·25 vs. 5·20 ELISA units (EU), P<0·001]. A kitchen worker with a positive rectal swab, negative blood culture and a high level of serum IgG anti-LPS (529·65 EU), was identified as a possible SPA carrier. No SPA was isolated from water or food samples. A survey of students' habits indicated drinking unboiled water as being the main reason for contracting the disease. Hand washing was the second most important factor. A food handler with possible SPA carriage could also have been a risk factor. Attention to maintaining a safe water supply, enhancing food-handler hygiene and proper hand washing can help to prevent similar outbreaks in the future.
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30
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Abstract
Typhoid and paratyphoid fever continue to be important causes of illness and death, particularly among children and adolescents in south-central and Southeast Asia, where enteric fever is associated with poor sanitation and unsafe food and water. High-quality incidence data from Asia are underpinning efforts to expand access to typhoid vaccines. Efforts are underway to develop vaccines that are immunogenic in infants after a single dose and that can be produced locally in countries of endemicity. The growing importance of Salmonella enterica serotype Paratyphi A in Asia is concerning. Antimicrobial resistance has sequentially emerged to traditional first-line drugs, fluoroquinolones, and third-generation cephalosporins, posing patient treatment challenges. Azithromycin has proven to be an effective alternative for treatment of uncomplicated typhoid fever. The availability of full genome sequences for S. enterica serotype Typhi and S. enterica serotype Paratyphi A confirms their place as monomorphic, human-adapted pathogens vulnerable to control measures if international efforts can be redoubled.
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Affiliation(s)
- John A Crump
- Enteric Diseases Epidemiology Branch, National Center for Zoonotic, Vectorborne, and Enteric Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia 30333, USA.
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31
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Kim S, Kim SH, Park JH, Lee KS, Park MS, Lee BK. Clustering analysis of Salmonella enterica serovar Typhi isolates in Korea by PFGE, ribotying, and phage typing. Foodborne Pathog Dis 2009; 6:733-8. [PMID: 19580446 DOI: 10.1089/fpd.2008.0212] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Salmonella enterica serovar Typhi is a Gram-negative bacterium causing the acute febrile disease typhoid fever. In Korea from 2004 to 2006, a total of 51 Salmonella Typhi isolates were identified in stool and blood from healthy carriers and patients with or without overseas travel histories. In this study, antibiogram, pulsed-field gel electrophoresis (PFGE), and automated ribotyping were performed as molecular epidemiological methods with phage typing as a classical subtyping tool of the isolates. Only two isolates were multidrug resistant and 82.3% of the isolates were susceptible to 16 antimicrobial agents tested. When the dendrogram was created based on the PFGE results, the subtypes could be clustered into five groups by 80% similarity criterion. The PFGE patterns of 31 isolates (60.8%) belonged to Cluster 3, the predominant cluster in the study. Three overseas travel-associated cases were differentiated into Cluster 4 of which three isolates were nalidixic acid or multidrug resistant. Major phage type and ribotype were A and PvuII-436-8-S-6, respectively. This study also showed the prevalence of PFGE Cluster 3 in Korea by clustering analysis and the link between some typhoid cases and travel to Cambodia, India, or Indonesia.
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Affiliation(s)
- Shukho Kim
- Center for Infectious Diseases, Korea National Institute of Health, Seoul, South Korea
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32
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Crump JA, Ram PK, Gupta SK, Miller MA, Mintz ED. Part I. Analysis of data gaps pertaining to Salmonella enterica serotype Typhi infections in low and medium human development index countries, 1984-2005. Epidemiol Infect 2008; 136:436-48. [PMID: 17686194 PMCID: PMC2870843 DOI: 10.1017/s0950268807009338] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/30/2007] [Indexed: 11/05/2022] Open
Abstract
There are only 10 contemporary, population-based studies of typhoid fever that evaluate disease incidence using blood culture for confirmation of cases. Reported incidence ranged from 13 to 976/100 000 persons per year. These studies are likely to have been done preferentially in high- incidence sites which makes generalization of data difficult. Only five of these studies reported mortality. Of these the median (range) mortality was 0% (0-1.8%). Since study conditions usually involved enhanced clinical management of patients and the studies were not designed to evaluate mortality as an outcome, their usefulness for generalizing case-fatality rates is uncertain. No contemporary population-based studies reported rates of complications. Hospital-based typhoid fever studies reported median (range) complication rates of 2.8% (0.6-4.9%) for intestinal perforation and case-fatality rates of 2.0% (0-14.8%). Rates of complications other than intestinal perforation were not reported in contemporary hospital-based studies. Hospital-based studies capture information on the most severe illnesses among persons who have access to health-care services limiting their generalizability. Only two studies have informed the current understanding of typhoid fever age distribution curves. Extrapolation from population-based studies suggests that most typhoid fever occurs among young children in Asia. To reduce gaps in the current understanding of typhoid fever incidence, complications, and case-fatality rate, large population-based studies using blood culture confirmation of cases are needed in representative sites, especially in low and medium human development index countries outside Asia.
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Affiliation(s)
- J A Crump
- Enteric Diseases Epidemiology Branch, National Center for Zoonotic, Vectorborne, and Enteric Diseases, Centers for Disease Control and Prevention, Atlanta, GA 30333, USA.
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Chart H, Cheasty T, de Pinna E, Siorvanes L, Wain J, Alam D, Nizami Q, Bhutta Z, Threlfall EJ. Serodiagnosis of Salmonella enterica serovar Typhi and S. enterica serovars Paratyphi A, B and C human infections. J Med Microbiol 2007; 56:1161-1166. [PMID: 17761477 DOI: 10.1099/jmm.0.47197-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The aim of this study was to evaluate an immunoassay for the detection of human serum antibodies to the LPS and flagellar antigens of Salmonella Typhi and Salmonella Paratyphi A, B and C, and to the Vi capsular polysaccharide of S. Typhi and S. Paratyphi C. A total of 330 sera were used; these originated from 15 patients who were culture-positive for S. Typhi and 15 healthy controls, together with 300 sera submitted to the Laboratory of Enteric Pathogens for Salmonella serodiagnosis. By SDS-PAGE/immunoblotting, all 15 sera from culture-positive patients had serum antibodies to the 9,12 LPS antigens and 10 had antibodies to the ‘d’ flagellar antigens. Of the 300 reference sera, 22 had antibodies to the 9,12 LPS antigens, one to the 1,4,5,12 LPS antigens and 12 to the 6,7 LPS antigens. Only two sera had antibodies to flagellar antigens, one of which bound to the ‘b’ and the other to the ‘d’ antigen. An ELISA was developed that successfully detected serum antibodies to the Vi capsular polysaccharides, but because of the kinetics of serum antibody production to the Vi, these antibodies may be of limited value in the serodiagnosis of acute infection with S. Typhi and S. Paratyphi C. The immunoassays described here provide a sensitive means of detecting serum antibodies to the LPS, flagellar and Vi antigens of S. Typhi and S. Paratyphi, and constitute a viable replacement for the Widal assay for the screening of sera. The Salmonella serodiagnosis protocols described here are the new standard operating procedures used by the Health Protection Agency's National Salmonella Reference Centre based in the Laboratory of Enteric Pathogens, Colindale, UK.
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Affiliation(s)
- Henrik Chart
- Laboratory of Enteric Pathogens, Department of Gastrointestinal Infections, Centre for Infections, Health Protection Agency, 61 Colindale Avenue, London NW9 5EQ, UK
| | - Thomas Cheasty
- Laboratory of Enteric Pathogens, Department of Gastrointestinal Infections, Centre for Infections, Health Protection Agency, 61 Colindale Avenue, London NW9 5EQ, UK
| | - Elizabeth de Pinna
- Laboratory of Enteric Pathogens, Department of Gastrointestinal Infections, Centre for Infections, Health Protection Agency, 61 Colindale Avenue, London NW9 5EQ, UK
| | - Lisa Siorvanes
- Laboratory of Enteric Pathogens, Department of Gastrointestinal Infections, Centre for Infections, Health Protection Agency, 61 Colindale Avenue, London NW9 5EQ, UK
| | - John Wain
- The Wellcome Trust Sanger Institute Wellcome Trust Genome Campus, Hinxton, Cambridge CB10 1SA, UK
| | - Didar Alam
- Department of Paediatrics and Child Health, The Aga Khan University Medical Centre, PO Box 3500, Karachi, Pakistan
| | - Qamarauddin Nizami
- Department of Paediatrics and Child Health, The Aga Khan University Medical Centre, PO Box 3500, Karachi, Pakistan
| | - Zulfiqar Bhutta
- Department of Paediatrics and Child Health, The Aga Khan University Medical Centre, PO Box 3500, Karachi, Pakistan
| | - E John Threlfall
- Laboratory of Enteric Pathogens, Department of Gastrointestinal Infections, Centre for Infections, Health Protection Agency, 61 Colindale Avenue, London NW9 5EQ, UK
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