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Kazazian L, Silver R, Rao CY, Park M, Ciuba C, Farron M, Henao OL. A toolkit for planning and implementing acute febrile illness (AFI) surveillance. PLOS GLOBAL PUBLIC HEALTH 2024; 4:e0003115. [PMID: 38635502 PMCID: PMC11025857 DOI: 10.1371/journal.pgph.0003115] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Accepted: 03/06/2024] [Indexed: 04/20/2024]
Abstract
Acute febrile illness (AFI) is a broad clinical syndrome with a wide range of potential infectious etiologies. The lack of accessible, standardized approaches to conducting AFI etiologic investigations has contributed to significant global gaps in data on the epidemiology of AFI. Based on lessons learned from years of supporting AFI sentinel surveillance worldwide, the U.S. Centers for Disease Control and Prevention developed the toolkit for planning and implementing AFI surveillance, described here. This toolkit provides a comprehensive yet flexible framework to guide researchers, public health officials, and other implementers in developing a strategy to identify and/or monitor the potential causes of AFI. The toolkit comprises a cohesive set of planning aids and supporting materials, including an implementation framework, generic protocol, several generic forms (including screening, case report, specimen collection and testing, and informed consent and assent), and a generic data dictionary. These materials incorporate key elements intended to harmonize approaches for AFI surveillance, as well as setting-specific components and considerations for adaptation based on local surveillance objectives and limitations. Appropriate adaptation and implementation of this toolkit may generate data that expand the global AFI knowledge base, strengthen countries' surveillance and laboratory capacity, and enhance outbreak detection and response efforts.
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Affiliation(s)
- Lilit Kazazian
- Global Epidemiology, Laboratory, and Surveillance Branch, Division of Global Health Protection, Global Health Center, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
| | - Rachel Silver
- Global Epidemiology, Laboratory, and Surveillance Branch, Division of Global Health Protection, Global Health Center, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
| | - Carol Y. Rao
- Global Epidemiology, Laboratory, and Surveillance Branch, Division of Global Health Protection, Global Health Center, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
| | - Michael Park
- Global Epidemiology, Laboratory, and Surveillance Branch, Division of Global Health Protection, Global Health Center, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
| | - Chandler Ciuba
- Global Epidemiology, Laboratory, and Surveillance Branch, Division of Global Health Protection, Global Health Center, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
| | - Madeline Farron
- Global Epidemiology, Laboratory, and Surveillance Branch, Division of Global Health Protection, Global Health Center, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
| | - Olga L. Henao
- Global Epidemiology, Laboratory, and Surveillance Branch, Division of Global Health Protection, Global Health Center, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
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Muthumbi EM, Mwanzu A, Mbae C, Bigogo G, Karani A, Mwarumba S, Verani JR, Kariuki S, Scott JAG. The epidemiology of fecal carriage of nontyphoidal Salmonella among healthy children and adults in three sites in Kenya. PLoS Negl Trop Dis 2023; 17:e0011716. [PMID: 37883602 PMCID: PMC10629669 DOI: 10.1371/journal.pntd.0011716] [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: 04/11/2023] [Revised: 11/07/2023] [Accepted: 10/10/2023] [Indexed: 10/28/2023] Open
Abstract
BACKGROUND Despite the importance of non-Typhoidal Salmonella (NTS) disease in Africa, epidemiologic data on carriage and transmission are few. These data are important to understand the transmission of NTS in Africa and to design control strategies. METHOD To estimate the prevalence of stool carriage of NTS in Kenya, we conducted a cross-sectional study in Kilifi, Nairobi, and Siaya, sites with a low, moderate and high incidence of invasive NTS disease, respectively. At each site, we randomly selected 100 participants in each age-group of 0-11 months, 12-59 months, 5-14 years, 15-54 years and ≥55 years. We collected stool, venous blood (for hemoglobin and malaria rapid tests), anthropometric measurements, and administered a questionnaire on Water Access Sanitation and Hygiene (WASH) practices. Stool samples were cultured on selective agar for Salmonella; suspect isolates underwent serotyping and antimicrobial susceptibility testing. RESULT Overall, 53 (3.5%) isolates of NTS were cultured from 1497 samples. Age-adjusted prevalence was 13.1% (95%CI 8.8-17.4) in Kilifi, 0.4% (95%CI 0-1.3) in Nairobi, and 0.9% (95%CI 0-2.0) in Siaya. Prevalence was highest among those aged 15-54 years (6.2%). Of 53 isolates; 5 were S. Enteritidis, 1 was S. Typhimurium. No S. Typhi was isolated. None of the risk factors were associated with carriage of NTS. All isolates were susceptible to all antibiotics tested, including ampicillin, chloramphenicol, ciprofloxacin and co-trimoxazole. CONCLUSION Prevalence of fecal carriage was high in Kilifi, an area of low incidence of invasive NTS disease and was low in areas of higher incidence in Nairobi and Siaya. The age-prevalence, risk factors, geographical and serotype distribution of NTS in carriage differs from invasive disease.
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Affiliation(s)
- Esther M. Muthumbi
- Kenya Medical Research Institute–Centre for Geographic Medicine Research, Coast, Kilifi, Kenya
- Department of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Alfred Mwanzu
- Kenya Medical Research Institute–Centre for Geographic Medicine Research, Coast, Kilifi, Kenya
| | - Cecilia Mbae
- Kenya Medical Research Institute–Centre for Microbiology Research, Nairobi, Kenya
| | - Godfrey Bigogo
- Kenya Medical Research Institute–Centre for Global Health Research, Kisumu, Kenya
| | - Angela Karani
- Kenya Medical Research Institute–Centre for Geographic Medicine Research, Coast, Kilifi, Kenya
| | - Salim Mwarumba
- Kenya Medical Research Institute–Centre for Geographic Medicine Research, Coast, Kilifi, Kenya
| | - Jennifer R. Verani
- U.S. Centers for Disease Control and Prevention, Division of Global Health Protection, Nairobi, Kenya
| | - Samuel Kariuki
- Kenya Medical Research Institute–Centre for Microbiology Research, Nairobi, Kenya
| | - J. Anthony G. Scott
- Kenya Medical Research Institute–Centre for Geographic Medicine Research, Coast, Kilifi, Kenya
- Department of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine, London, United Kingdom
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Green EW, Ndiaye M, Hossain IM, Olatunji YA, Sahito SM, Salaudeen R, Badji H, Manjang A, Ceesay L, Hill PC, Greenwood B, Mackenzie GA. Pneumonia, Meningitis, and Septicemia in Adults and Older Children in Rural Gambia: 8 Years of Population-Based Surveillance. Clin Infect Dis 2023; 76:694-703. [PMID: 35903006 PMCID: PMC9938739 DOI: 10.1093/cid/ciac603] [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: 02/09/2022] [Revised: 07/14/2022] [Accepted: 07/19/2022] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND Representative data describing serious infections in children aged ≥5 years and adults in Africa are limited. METHODS We conducted population-based surveillance for pneumonia, meningitis, and septicemia in a demographic surveillance area in The Gambia between 12 May 2008 and 31 December 2015. We used standardized criteria to identify, diagnose, and investigate patients aged ≥5 years using conventional microbiology and radiology. RESULTS We enrolled 1638 of 1657 eligible patients and investigated 1618. Suspected pneumonia, septicemia, or meningitis was diagnosed in 1392, 135, and 111 patients, respectively. Bacterial pathogens from sterile sites were isolated from 105 (7.5%) patients with suspected pneumonia, 11 (8.1%) with suspected septicemia, and 28 (25.2%) with suspected meningitis. Streptococcus pneumoniae (n = 84), Neisseria meningitidis (n = 16), and Staphylococcus aureus (n = 15) were the most common pathogens. Twenty-eight (1.7%) patients died in hospital and 40 (4.1%) died during the 4 months after discharge. Thirty postdischarge deaths occurred in patients aged ≥10 years with suspected pneumonia. The minimum annual incidence was 133 cases per 100 000 person-years for suspected pneumonia, 13 for meningitis, 11 for septicemia, 14 for culture-positive disease, and 46 for radiological pneumonia. At least 2.7% of all deaths in the surveillance area were due to suspected pneumonia, meningitis, or septicemia. CONCLUSIONS Pneumonia, meningitis, and septicemia in children aged ≥5 years and adults in The Gambia are responsible for significant morbidity and mortality. Many deaths occur after hospital discharge and most cases are culture negative. Improvements in prevention, diagnosis, inpatient, and follow-up management are urgently needed.
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Affiliation(s)
- Edward W Green
- Medical Research Council Unit The Gambia, London School of Hygiene and Tropical Medicine, Fajara, The Gambia.,Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Malick Ndiaye
- Medical Research Council Unit The Gambia, London School of Hygiene and Tropical Medicine, Fajara, The Gambia
| | - Ilias M Hossain
- Medical Research Council Unit The Gambia, London School of Hygiene and Tropical Medicine, Fajara, The Gambia
| | - Yekini A Olatunji
- Medical Research Council Unit The Gambia, London School of Hygiene and Tropical Medicine, Fajara, The Gambia
| | - Shah M Sahito
- Medical Research Council Unit The Gambia, London School of Hygiene and Tropical Medicine, Fajara, The Gambia
| | - Rasheed Salaudeen
- Medical Research Council Unit The Gambia, London School of Hygiene and Tropical Medicine, Fajara, The Gambia
| | - Henry Badji
- Medical Research Council Unit The Gambia, London School of Hygiene and Tropical Medicine, Fajara, The Gambia
| | - Ahmed Manjang
- Medical Research Council Unit The Gambia, London School of Hygiene and Tropical Medicine, Fajara, The Gambia
| | - Lamin Ceesay
- Ministry of Health and Social Welfare, Banjul, The Gambia
| | - Philip C Hill
- Centre for International Health, University of Otago, Dunedin, New Zealand
| | - Brian Greenwood
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Grant A Mackenzie
- Medical Research Council Unit The Gambia, London School of Hygiene and Tropical Medicine, Fajara, The Gambia.,Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom.,Murdoch Children's Research Institute, Melbourne, Australia
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4
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Kariuki S, Kering K, Wairimu C, Onsare R, Mbae C. Antimicrobial Resistance Rates and Surveillance in Sub-Saharan Africa: Where Are We Now? Infect Drug Resist 2022; 15:3589-3609. [PMID: 35837538 PMCID: PMC9273632 DOI: 10.2147/idr.s342753] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Accepted: 06/16/2022] [Indexed: 01/03/2023] Open
Abstract
Introduction Although antimicrobials have traditionally been used to treat infections and improve health outcomes, resistance to commonly used antimicrobials has posed a major challenge. An estimated 700,000 deaths occur globally every year as a result of infections caused by antimicrobial-resistant pathogens. Antimicrobial resistance (AMR) also contributes directly to the decline in the global economy. In 2019, sub-Saharan Africa (SSA) had the highest mortality rate (23.5 deaths per 100,000) attributable to AMR compared to other regions. Methods We searched PubMed for articles relevant to AMR in pathogens in the WHO-GLASS list and in other infections of local importance in SSA. In this review, we focused on AMR rates and surveillance of AMR for these priority pathogens and some of the most encountered pathogens of public health significance. In addition, we reviewed the implementation of national action plans to mitigate against AMR in countries in SSA. Results and Discussion The SSA region is disproportionately affected by AMR, in part owing to the prevailing high levels of poverty, which result in a high burden of infectious diseases, poor regulation of antimicrobial use, and a lack of alternatives to ineffective antimicrobials. The global action plan as a strategy for prevention and combating AMR has been adopted by most countries, but fewer countries are able to fully implement country-specific action plans, and several challenges exist in many settings. Conclusion A concerted One Health approach will be required to ramp up implementation of action plans in the region. In addition to AMR surveillance, effective implementation of infection prevention and control, water, sanitation, and hygiene, and antimicrobial stewardship programs will be key cost-effective strategies in helping to tackle AMR.
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Affiliation(s)
- Samuel Kariuki
- Centre for Microbiology Research, Kenya Medical Research Institute, Nairobi, Kenya,Correspondence: Samuel Kariuki, Centre for Microbiology Research, Kenya Medical Research Institute, Nairobi, Kenya, Email
| | - Kelvin Kering
- Centre for Microbiology Research, Kenya Medical Research Institute, Nairobi, Kenya
| | - Celestine Wairimu
- Centre for Microbiology Research, Kenya Medical Research Institute, Nairobi, Kenya
| | - Robert Onsare
- Centre for Microbiology Research, Kenya Medical Research Institute, Nairobi, Kenya
| | - Cecilia Mbae
- Centre for Microbiology Research, Kenya Medical Research Institute, Nairobi, Kenya
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Marchello CS, Birkhold M, Crump JA, Martin LB, Ansah MO, Breghi G, Canals R, Fiorino F, Gordon MA, Kim JH, Hamaluba M, Hanumunthadu B, Jacobs J, Kariuki S, Malvolti S, Mantel C, Marks F, Medaglini D, Mogasale V, Msefula CL, Muthumbi E, Niyrenda TS, Onsare R, Owusu-Dabo E, Pettini E, Ramasamy MN, Soura BA, Spadafina T, Tack B. Complications and mortality of non-typhoidal salmonella invasive disease: a global systematic review and meta-analysis. THE LANCET INFECTIOUS DISEASES 2022; 22:692-705. [PMID: 35114140 PMCID: PMC9021030 DOI: 10.1016/s1473-3099(21)00615-0] [Citation(s) in RCA: 65] [Impact Index Per Article: 32.5] [Reference Citation Analysis] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Revised: 08/03/2021] [Accepted: 09/06/2021] [Indexed: 01/07/2023]
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Marchello CS, Fiorino F, Pettini E, Crump JA. Incidence of non-typhoidal Salmonella invasive disease: A systematic review and meta-analysis. J Infect 2021; 83:523-532. [PMID: 34260964 PMCID: PMC8627500 DOI: 10.1016/j.jinf.2021.06.029] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Accepted: 06/28/2021] [Indexed: 11/22/2022]
Abstract
OBJECTIVES We sought to collate and summarize high-quality data on non-typhoidal Salmonella invasive disease (iNTS) incidence to provide contemporary incidence estimates by location and year. METHODS We systematically searched the databases Embase + MEDLINE, Web of Science, and PubMed for articles published on the incidence of iNTS from inception of the database through 8 May 2020 with no language, country, date, or demographic restrictions applied. A meta-analysis was performed to report pooled iNTS incidence as a rate of cases per 100,000 per year. RESULTS Among 13 studies eligible for analysis, there were 68 estimates of incidence. Overall pooled incidence (95% CI) was 44.8 (31.5-60.5) per 100,000 persons per year. When stratified by region, pooled incidence was significantly higher in Africa than Asia, 51.0 (36.3-68.0) compared to 1.0 (0.2-2.5), respectively. Incidence was consistently higher in children aged <5 years compared with older age groups. Incidence displayed considerable heterogeneity in both place and time, varying substantially between locations and over consecutive years in the same location. CONCLUSIONS iNTS incidence varies by region, location, age group, and over time. Concerted efforts are needed to address the limited high-quality data available on iNTS disease incidence.
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Affiliation(s)
- Christian S Marchello
- Centre for International Health, University of Otago, PO Box 56, Dunedin 9054, New Zealand
| | | | | | - John A Crump
- Centre for International Health, University of Otago, PO Box 56, Dunedin 9054, New Zealand.
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Crump JA, Thomas KM, Benschop J, Knox MA, Wilkinson DA, Midwinter AC, Munyua P, Ochieng JB, Bigogo GM, Verani JR, Widdowson MA, Prinsen G, Cleaveland S, Karimuribo ED, Kazwala RR, Mmbaga BT, Swai ES, French NP, Zadoks RN. Investigating the meat pathway as a source of human nontyphoidal Salmonella bloodstream infections and diarrhea in East Africa. Clin Infect Dis 2020; 73:e1570-e1578. [PMID: 32777036 PMCID: PMC8492120 DOI: 10.1093/cid/ciaa1153] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Accepted: 08/04/2020] [Indexed: 11/29/2022] Open
Abstract
Background Salmonella Enteritidis and Salmonella Typhimurium are major causes of bloodstream infection and diarrheal disease in East Africa. Sources of human infection, including the role of the meat pathway, are poorly understood. Methods We collected cattle, goat, and poultry meat pathway samples from December 2015 through August 2017 in Tanzania and isolated Salmonella using standard methods. Meat pathway isolates were compared with nontyphoidal serovars of Salmonella enterica (NTS) isolated from persons with bloodstream infections and diarrheal disease from 2007 through 2017 from Kenya by core genome multi-locus sequence typing (cgMLST). Isolates were characterized for antimicrobial resistance, virulence genes, and diversity. Results We isolated NTS from 164 meat pathway samples. Of 172 human NTS isolates, 90 (52.3%) from stool and 82 (47.7%) from blood, 53 (30.8%) were Salmonella Enteritidis sequence type (ST) 11 and 62 (36.0%) were Salmonella Typhimurium ST313. We identified cgMLST clusters within Salmonella Enteritidis ST11, Salmonella Heidelberg ST15, Salmonella Typhimurium ST19, and Salmonella II 42:r:- ST1208 that included both human and meat pathway isolates. Salmonella Typhimurium ST313 was isolated exclusively from human samples. Human and poultry isolates bore more antimicrobial resistance and virulence genes and were less diverse than isolates from other sources. Conclusions Our findings suggest that the meat pathway may be an important source of human infection with some clades of Salmonella Enteritidis ST11 in East Africa, but not of human infection by Salmonella Typhimurium ST313. Research is needed to systematically examine the contributions of other types of meat, animal products, produce, water, and the environment to nontyphoidal Salmonella disease in East Africa.
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Affiliation(s)
- John A Crump
- Centre for International Health, University of Otago, Dunedin, New Zealand.,Kilimanjaro Clinical Research Institute, Kilimanjaro Christian Medical Centre, Moshi, Tanzania.,Kilimanjaro Christian Medical University College, Moshi, Tanzania
| | - Kate M Thomas
- Centre for International Health, University of Otago, Dunedin, New Zealand
| | - Jackie Benschop
- School of Veterinary Science, Massey University, Palmerston North, New Zealand
| | - Matthew A Knox
- School of Veterinary Science, Massey University, Palmerston North, New Zealand
| | - David A Wilkinson
- School of Veterinary Science, Massey University, Palmerston North, New Zealand
| | - Anne C Midwinter
- School of Veterinary Science, Massey University, Palmerston North, New Zealand
| | - Peninah Munyua
- Division of Global Health Protection, US Centers for Disease Control and Prevention, Nairobi, Kenya
| | - John B Ochieng
- Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Godfrey M Bigogo
- Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Jennifer R Verani
- Division of Global Health Protection, US Centers for Disease Control and Prevention, Nairobi, Kenya
| | - Marc-Alain Widdowson
- Division of Global Health Protection, US Centers for Disease Control and Prevention, Nairobi, Kenya.,Institute of Tropical Medicine, Antwerp, Belgium
| | - Gerard Prinsen
- School of People, Environment and Planning, Massey University, Palmerston North, New Zealand
| | - Sarah Cleaveland
- Institute of Biodiversity, Animal Health, and Comparative Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, Scotland, United Kingdom
| | - Esron D Karimuribo
- College of Veterinary Medicine and Biomedical Sciences, Sokoine University of Agriculture, Morogoro, Tanzania
| | - Rudovick R Kazwala
- College of Veterinary Medicine and Biomedical Sciences, Sokoine University of Agriculture, Morogoro, Tanzania
| | - Blandina T Mmbaga
- Kilimanjaro Clinical Research Institute, Kilimanjaro Christian Medical Centre, Moshi, Tanzania.,Kilimanjaro Christian Medical University College, Moshi, Tanzania
| | - Emanuel S Swai
- Department of Veterinary Services, Ministry of Livestock and Fisheries, Dodoma, Tanzania
| | - Nigel P French
- School of Veterinary Science, Massey University, Palmerston North, New Zealand
| | - Ruth N Zadoks
- Institute of Biodiversity, Animal Health, and Comparative Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, Scotland, United Kingdom.,Sydney School of Veterinary Science, University of Sydney, Sydney, Australia
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Luvsansharav UO, Wakhungu J, Grass J, Oneko M, Nguyen V, Bigogo G, Ogola E, Audi A, Onyango D, Hamel MJ, Montgomery JM, Fields PI, Mahon BE. Exploration of risk factors for ceftriaxone resistance in invasive non-typhoidal Salmonella infections in western Kenya. PLoS One 2020; 15:e0229581. [PMID: 32126103 PMCID: PMC7053705 DOI: 10.1371/journal.pone.0229581] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Accepted: 02/10/2020] [Indexed: 01/21/2023] Open
Abstract
Multidrug-resistant non-typhoidal Salmonella (NTS) infection has emerged as a prominent cause of invasive infections in Africa. We investigated the prevalence of ceftriaxone-resistant invasive NTS infections, conducted exploratory analysis of risk factors for resistance, and described antimicrobial use in western Kenya. We conducted a secondary analysis of existing laboratory, epidemiology, and clinical data from three independent projects, a malaria vaccine trial, a central nervous system (CNS) study, and the International Emerging Infections Program morbidity surveillance (surveillance program) during 2009-2014. We calculated odds ratios (OR) with 95% confidence intervals (CI) for ceftriaxone-resistant NTS infections compared with ceftriaxone-susceptible infections. We surveyed hospitals, pharmacies, and animal drug retailers about the availability and use of antimicrobials. In total, 286 invasive NTS infections were identified in the three projects; 43 NTS isolates were ceftriaxone-resistant. The absolute prevalence of ceftriaxone resistance varied among these methodologically diverse projects, with 18% (16/90) of isolates resistant to ceftriaxone in the vaccine trial, 89% (16/18) in the CNS study, and 6% (11/178) in the surveillance program. Invasive ceftriaxone-resistant infections increased over time. Most ceftriaxone-resistant isolates were co-resistant to multiple other antimicrobials. Having an HIV-positive mother (OR = 3.7; CI = 1.2-11.4) and taking trimethoprim-sulfamethoxazole for the current illness (OR = 9.6, CI = 1.2-78.9) were significantly associated with acquiring ceftriaxone-resistant invasive NTS infection. Ceftriaxone and other antibiotics were widely prescribed; multiple issues related to prescription practices and misuse were identified. In summary, ceftriaxone-resistant invasive NTS infection is increasing and limiting treatment options for serious infections. Efforts are ongoing to address the urgent need for improved microbiologic diagnostic capacity and an antimicrobial surveillance system in Kenya.
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Affiliation(s)
- Ulzii-Orshikh Luvsansharav
- Epidemic Intelligence Service, Epidemiology Workforce Branch, Division of Scientific Education and Professional Development, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
- Enteric Diseases Epidemiology Branch, Division of Foodborne, Waterborne and Environmental Diseases, National Center for Emerging Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
| | - James Wakhungu
- Field Epidemiology and Laboratory Training Program, Ministry of Health, Nairobi, Kenya
| | - Julian Grass
- Enteric Diseases Epidemiology Branch, Division of Foodborne, Waterborne and Environmental Diseases, National Center for Emerging Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
| | - Martina Oneko
- Centre for Global Health Research, Kenya Medical Research Institute, Nairobi, Kenya
| | - Von Nguyen
- Epidemic Intelligence Service, Epidemiology Workforce Branch, Division of Scientific Education and Professional Development, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
- Enteric Diseases Epidemiology Branch, Division of Foodborne, Waterborne and Environmental Diseases, National Center for Emerging Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
| | - Godfrey Bigogo
- Centre for Global Health Research, Kenya Medical Research Institute, Nairobi, Kenya
| | - Eric Ogola
- Centre for Global Health Research, Kenya Medical Research Institute, Nairobi, Kenya
| | - Allan Audi
- Centre for Global Health Research, Kenya Medical Research Institute, Nairobi, Kenya
| | | | - Mary J Hamel
- Malaria Branch, Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
| | - Joel M Montgomery
- Division of Global Health Protection, Centers for Disease Control and Prevention, Nairobi, Kenya
| | - Patricia I Fields
- Enteric Diseases Laboratory Branch, Division of Foodborne, Waterborne and Environmental Diseases, National Center for Emerging Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
| | - Barbara E Mahon
- Enteric Diseases Epidemiology Branch, Division of Foodborne, Waterborne and Environmental Diseases, National Center for Emerging Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
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Post AS, Diallo SN, Guiraud I, Lompo P, Tahita MC, Maltha J, Van Puyvelde S, Mattheus W, Ley B, Thriemer K, Rouamba E, Derra K, Deborggraeve S, Tinto H, Jacobs J. Supporting evidence for a human reservoir of invasive non-Typhoidal Salmonella from household samples in Burkina Faso. PLoS Negl Trop Dis 2019; 13:e0007782. [PMID: 31609964 PMCID: PMC6812844 DOI: 10.1371/journal.pntd.0007782] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2019] [Revised: 10/24/2019] [Accepted: 09/14/2019] [Indexed: 11/18/2022] Open
Abstract
Background Salmonella Typhimurium and Enteritidis are major causes of bloodstream infection in children in sub-Saharan Africa. This study assessed evidence for their zoonotic versus human reservoir. Methods Index patients were children with blood culture confirmed Salmonella infection recruited during a microbiological surveillance study in Nanoro, rural Burkina between May 2013 and August 2014. After consent, their households were visited. Stool from household members and livestock (pooled samples per species) as well as drinking water were cultured for Salmonella. Isolates with identical serotype obtained from index patient and any household sample were defined as “paired isolates” and assessed for genetic relatedness by multilocus variable number tandem-repeat analysis (MLVA) and whole-genome sequencing (WGS). Results Twenty-nine households were visited for 32/42 (76.2%) eligible index patients: two households comprised two index patients each, and in a third household the index patient had a recurrent infection. Among the 32 index patients, serotypes were Salmonella Typhimurium (n = 26), Salmonella Enteritidis (n = 5) and Salmonella Freetown (n = 1). All Typhimurium isolates were sequence type (ST)313. Median delay between blood culture sampling and household visits was 13 days (range 6–26). Salmonella was obtained from 16/186 (8.6%) livestock samples (13 serotypes) and 18/290 (6.2%) household members (9 serotypes). None of the water samples yielded Salmonella. Paired Salmonella Typhimurium isolates were obtained from three households representing four index patients. MLVA types were identical in two pairs and similar in the third (consisting of two index patients and one household member). WGS showed a strong genetic relatedness with 0 to 2 core genome SNPs difference between pairs on a household level. Livestock samples did not yield any Salmonella Typhimurium or Salmonella Enteritidis, and the latter was exclusively obtained from blood culture. Other serotypes shared by human and/or livestock carriers in the same household were Salmonella Derby, Drac, Tennessee and Muenster. Conclusions/Significance The current study provides further evidence of a human reservoir for invasive non-Typhoidal Salmonella (iNTS) in sub-Saharan Africa. Non-Typhoidal Salmonella—particularly Salmonella Typhimurium sequence type (ST) 313—are among the most common causes of bloodstream infection in children in sub-Saharan Africa. To assess transmission and reservoir of this invasive serotype we performed a blood culture surveillance study among children < 15 years (index patients) in Nanoro, rural Burkina Faso. In case of blood culture confirmed invasive Non-Typhoidal Salmonella (iNTS) infection among index patients a household survey was performed, during which stool samples from household members, stool samples from livestock and water samples were obtained and cultured for Salmonella. Salmonella isolates obtained from blood culture of index patients were compared for genetic relatedness with Salmonella isolates obtained from samples taken from their corresponding household. In three households we found Salmonella Typhimurium ST 313 among both index patient and the stool sample of a household member, we found a strong genetic relatedness within each pair. There were no matching serotypes between index patients and livestock samples or water samples within households. Clusters from other serotypes were restricted to stool samples from household members and different species of livestock. Our results support the theory that iNTS has a human reservoir.
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Affiliation(s)
- Annelies S. Post
- Department of Clinical Sciences, Institute of Tropical Medicine (ITM), Antwerp, Belgium
- Nijmegen Institute of International Health, Radboud university medical centre, Nijmegen, the Netherlands
- * E-mail: (ASP); (SND)
| | - Seydou Nakanabo Diallo
- IRSS/Clinical Research Unit of Nanoro (CRUN), Nanoro, Burkina Faso
- Centre Muraz, Bobo-Dioulasso, Burkina Faso
- * E-mail: (ASP); (SND)
| | - Issa Guiraud
- IRSS/Clinical Research Unit of Nanoro (CRUN), Nanoro, Burkina Faso
- Center for Molecular and Vascular Biology, University of Leuven (KU Leuven), Leuven, Belgium
| | - Palpouguini Lompo
- IRSS/Clinical Research Unit of Nanoro (CRUN), Nanoro, Burkina Faso
- Center for Molecular and Vascular Biology, University of Leuven (KU Leuven), Leuven, Belgium
| | | | - Jessica Maltha
- Department of Clinical Sciences, Institute of Tropical Medicine (ITM), Antwerp, Belgium
- Center for Molecular and Vascular Biology, University of Leuven (KU Leuven), Leuven, Belgium
| | - Sandra Van Puyvelde
- Department of Biomedical Sciences, Institute of Tropical Medicine (ITM), Antwerp, Belgium
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, United Kingdom
| | - Wesley Mattheus
- Belgian National Centre for Salmonella, Sciensano, Brussels, Belgium
| | - Benedikt Ley
- Department of Clinical Sciences, Institute of Tropical Medicine (ITM), Antwerp, Belgium
- Department for Global Health, Menzies School of Health Research, Darwin, Australia
| | - Kamala Thriemer
- Department of Clinical Sciences, Institute of Tropical Medicine (ITM), Antwerp, Belgium
- Department for Global Health, Menzies School of Health Research, Darwin, Australia
| | - Eli Rouamba
- IRSS/Clinical Research Unit of Nanoro (CRUN), Nanoro, Burkina Faso
| | - Karim Derra
- IRSS/Clinical Research Unit of Nanoro (CRUN), Nanoro, Burkina Faso
| | - Stijn Deborggraeve
- Department of Biomedical Sciences, Institute of Tropical Medicine (ITM), Antwerp, Belgium
| | - Halidou Tinto
- IRSS/Clinical Research Unit of Nanoro (CRUN), Nanoro, Burkina Faso
- Centre Muraz, Bobo-Dioulasso, Burkina Faso
- Université supérieur des sciences de la santé, Université polytechnique de Bobo-Dioulasso, Burkina Faso
| | - Jan Jacobs
- Department of Clinical Sciences, Institute of Tropical Medicine (ITM), Antwerp, Belgium
- Department of Microbiology and Immunology, University of Leuven (KU Leuven), Leuven, Belgium
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10
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Silverman RA, John-Stewart GC, Beck IA, Milne R, Kiptinness C, McGrath CJ, Richardson BA, Chohan B, Sakr SR, Frenkel LM, Chung MH. Predictors of mortality within the first year of initiating antiretroviral therapy in urban and rural Kenya: A prospective cohort study. PLoS One 2019; 14:e0223411. [PMID: 31584992 PMCID: PMC6777822 DOI: 10.1371/journal.pone.0223411] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2019] [Accepted: 09/21/2019] [Indexed: 12/25/2022] Open
Abstract
Introduction Despite increased treatment availability, HIV-infected individuals continue to start antiretroviral therapy (ART) late in disease progression, increasing early mortality risk. Materials and methods Nested prospective cohort study within a randomized clinical trial of adult patients initiating ART at clinics in urban Nairobi and rural Maseno, Kenya, between 2013–2014. We estimated mortality incidence rates following ART initiation and used Cox proportional hazards regression to identify predictors of mortality within 12 months of ART initiation. Analyses were stratified by clinic site to examine differences in mortality correlates and risk by location. Results Among 811 participants initiated on ART, the mortality incidence rate within a year of initiating ART was 7.44 per 100 person-years (95% CI 5.71, 9.69). Among 207 Maseno and 612 Nairobi participants initiated on ART, the mortality incidence rates (per 100 person-years) were 12.78 (95% CI 8.49, 19.23) and 5.72 (95% CI 4.05, 8.09). Maseno had a 2.20-fold greater risk of mortality than Nairobi (95% CI 1.29, 3.76; P = 0.004). This association remained [adjusted hazard ratio (HR) = 2.09 (95% CI 1.17, 3.74); P = 0.013] when adjusting for age, gender, education, pre-treatment drug resistance (PDR), and CD4 count, but not when adjusting for BMI. In unadjusted analyses, other predictors (P<0.05) of mortality included male gender (HR = 1.74), age (HR = 1.04 for 1-year increase), fewer years of education (HR = 0.92 for 1-year increase), unemployment (HR = 1.89), low body mass index (BMI<18.5 m/kg2; HR = 4.99), CD4 count <100 (HR = 11.67) and 100–199 (HR = 3.40) vs. 200–350 cells/μL, and pre-treatment drug resistance (PDR; HR = 2.49). The increased mortality risk associated with older age, males, and greater education remained when adjusted for location, age, education and PDR, but not when adjusted for BMI and CD4 count. PDR remained associated with increased mortality risk when adjusted for location, age, gender, education, and BMI, but not when adjusted for CD4 count. CD4 and BMI associations with increased mortality risk persisted in multivariable analyses. Despite similar baseline CD4 counts across locations, mortality risk associated with low CD4 count, low BMI, and PDR was greater in Maseno than Nairobi in stratified analyses. Conclusions High short-term post-ART mortality was observed, partially due to low CD4 count and BMI at presentation, especially in the rural setting. Male gender, older age, and markers of lower socioeconomic status were also associated with greater mortality risk. Engaging patients earlier in HIV infection remains critical. PDR may influence short-term mortality and further studies to optimize management will be important in settings with increasing PDR.
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Affiliation(s)
- Rachel A. Silverman
- Department of Epidemiology, University of Washington, Seattle, Washington, United States of America
- Department of Global Health, University of Washington, Seattle, Washington, United States of America
- Department of Population Health Sciences, Virginia Polytechnic Institute and State University, Blacksburg, Virginia, United States of America
- * E-mail:
| | - Grace C. John-Stewart
- Department of Epidemiology, University of Washington, Seattle, Washington, United States of America
- Department of Global Health, University of Washington, Seattle, Washington, United States of America
- Department of Medicine, University of Washington, Seattle, Washington, United States of America
- Pediatrics, University of Washington, Seattle, Washington, United States of America
| | - Ingrid A. Beck
- Seattle Children’s Research Institute, Seattle, Washington, United States of America
| | - Ross Milne
- Seattle Children’s Research Institute, Seattle, Washington, United States of America
| | - Catherine Kiptinness
- Department of Global Health, University of Washington, Seattle, Washington, United States of America
| | - Christine J. McGrath
- Department of Global Health, University of Washington, Seattle, Washington, United States of America
| | - Barbra A. Richardson
- Department of Global Health, University of Washington, Seattle, Washington, United States of America
- Department of Biostatistics, University of Washington, Seattle, Washington, United States of America
| | - Bhavna Chohan
- Department of Global Health, University of Washington, Seattle, Washington, United States of America
- Kenya Medical Research Institute (KEMRI), Nairobi, Kenya
| | | | - Lisa M. Frenkel
- Department of Global Health, University of Washington, Seattle, Washington, United States of America
- Department of Medicine, University of Washington, Seattle, Washington, United States of America
- Pediatrics, University of Washington, Seattle, Washington, United States of America
- Seattle Children’s Research Institute, Seattle, Washington, United States of America
- Department of Laboratory Medicine, University of Washington, Seattle, Washington, United States of America
| | - Michael H. Chung
- Department of Epidemiology, University of Washington, Seattle, Washington, United States of America
- Department of Global Health, University of Washington, Seattle, Washington, United States of America
- Department of Medicine, University of Washington, Seattle, Washington, United States of America
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11
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Hunsperger E, Juma B, Onyango C, Ochieng JB, Omballa V, Fields BS, Njenga MK, Mwangi J, Bigogo G, Omore R, Otieno N, Chaves SS, Munyua P, Njau DM, Verani J, Lowther S, Breiman RF, Montgomery JM, De Cock KM, Widdowson MA. Building laboratory capacity to detect and characterize pathogens of public and global health security concern in Kenya. BMC Public Health 2019; 19:477. [PMID: 32326916 PMCID: PMC6696698 DOI: 10.1186/s12889-019-6770-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Since 1979, multiple CDC Kenya programs have supported the development of diagnostic expertise and laboratory capacity in Kenya. In 2004, CDC’s Global Disease Detection (GDD) program within the Division of Global Health Protection in Kenya (DGHP-Kenya) initiated close collaboration with Kenya Medical Research Institute (KEMRI) and developed a laboratory partnership called the Diagnostic and Laboratory Systems Program (DLSP). DLSP built onto previous efforts by malaria, human immunodeficiency virus (HIV) and tuberculosis (TB) programs and supported the expansion of the diagnostic expertise and capacity in KEMRI and the Ministry of Health. First, DLSP developed laboratory capacity for surveillance of diarrheal, respiratory, zoonotic and febrile illnesses to understand the etiology burden of these common illnesses and support evidenced-based decisions on vaccine introductions and recommendations in Kenya. Second, we have evaluated and implemented new diagnostic technologies such as TaqMan Array Cards (TAC) to detect emerging or reemerging pathogens and have recently added a next generation sequencer (NGS). Third, DLSP provided rapid laboratory diagnostic support for outbreak investigation to Kenya and regional countries. Fourth, DLSP has been assisting the Kenya National Public Health laboratory-National Influenza Center and microbiology reference laboratory to obtain World Health Organization (WHO) certification and ISO15189 accreditation respectively. Fifth, we have supported biosafety and biosecurity curriculum development to help Kenyan laboratories safely and appropriately manage infectious pathogens. These achievements, highlight how in collaboration with existing CDC programs working on HIV, tuberculosis and malaria, the Global Health Security Agenda can have significantly improve public health in Kenya and the region. Moreover, Kenya provides an example as to how laboratory science can help countries detect and control of infectious disease outbreaks and other public health threats more rapidly, thus enhancing global health security.
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Affiliation(s)
- Elizabeth Hunsperger
- Centers for Disease Control and Prevention (CDC), Center for Global Health (CGH), Division of Global Health Protection (DGHP), Nairobi, Kenya. .,CDC, CGH, DGHP, Epidemiology, Informatics, Surveillance and Laboratory Branch, Atlanta, GA, USA.
| | - Bonventure Juma
- Centers for Disease Control and Prevention (CDC), Center for Global Health (CGH), Division of Global Health Protection (DGHP), Nairobi, Kenya
| | - Clayton Onyango
- Centers for Disease Control and Prevention (CDC), Center for Global Health (CGH), Division of Global Health Protection (DGHP), Nairobi, Kenya
| | - John B Ochieng
- Kenya Medical Research Institute (KEMRI), Center for Global Health Research (CGHR), Kisumu, Kenya
| | | | - Barry S Fields
- CDC, CGH, DGHP, Epidemiology, Informatics, Surveillance and Laboratory Branch, Atlanta, GA, USA
| | | | - Jane Mwangi
- CDC, CGH, Division of Global HIV and TB (DGHT), Nairobi, Kenya
| | - Godfrey Bigogo
- Kenya Medical Research Institute (KEMRI), Center for Global Health Research (CGHR), Kisumu, Kenya
| | - Richard Omore
- Kenya Medical Research Institute (KEMRI), Center for Global Health Research (CGHR), Kisumu, Kenya
| | - Nancy Otieno
- Kenya Medical Research Institute (KEMRI), Center for Global Health Research (CGHR), Kisumu, Kenya
| | - Sandra S Chaves
- CDC, National Center for Immunization and Respiratory Diseases, Influenza Division, Nairobi, Kenya
| | - Peninah Munyua
- Centers for Disease Control and Prevention (CDC), Center for Global Health (CGH), Division of Global Health Protection (DGHP), Nairobi, Kenya
| | - Daniel Macharia Njau
- Centers for Disease Control and Prevention (CDC), Center for Global Health (CGH), Division of Global Health Protection (DGHP), Nairobi, Kenya
| | - Jennifer Verani
- Centers for Disease Control and Prevention (CDC), Center for Global Health (CGH), Division of Global Health Protection (DGHP), Nairobi, Kenya.,CDC, CGH, DGHP, Epidemiology, Informatics, Surveillance and Laboratory Branch, Atlanta, GA, USA
| | - Sara Lowther
- CDC, DGHP, Workforce Institute Development Branch, Nairobi, Kenya
| | - Robert F Breiman
- Emory Global Health Institute, Emory University, Atlanta, GA, USA
| | - Joel M Montgomery
- CDC, CGH, DGHP, Epidemiology, Informatics, Surveillance and Laboratory Branch, Atlanta, GA, USA
| | - Kevin M De Cock
- CDC, CGH, Division of Global HIV and TB (DGHT), Nairobi, Kenya
| | - Marc-Alain Widdowson
- Centers for Disease Control and Prevention (CDC), Center for Global Health (CGH), Division of Global Health Protection (DGHP), Nairobi, Kenya.,CDC, CGH, DGHP, Epidemiology, Informatics, Surveillance and Laboratory Branch, Atlanta, GA, USA
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12
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Abstract
Nontyphoidal salmonellae (NTS) are a major cause of invasive (iNTS) disease in sub-Saharan Africa, manifesting as bacteremia and meningitis. Available epidemiological data indicate that iNTS disease is endemic in much of the region. Antimicrobial resistance is common and case fatality rates are high. There are well-characterized clinical associations with iNTS disease, including young age, HIV infection, malaria, malnutrition, anemia, and sickle cell disease. However, the clinical presentation of iNTS disease is often with fever alone, so clinical diagnosis is impossible without blood culture confirmation. No vaccine is currently available, making this a priority area for global health research. Over the past ten years, it has emerged that iNTS disease in Africa is caused by distinct pathovars of Salmonella Typhimurium, belonging to sequence type ST313, and Salmonella Enteritidis. These are characterized by genome degradation and appear to be adapting to an invasive lifestyle. Investigation of rare patients with primary immunodeficiencies has suggested a key role for interferon gamma-mediated immunity in host defense against NTS. This concept has been supported by recent population-based host genetic studies in African children. In contrast, immunoepidemiological studies from Africa indicate an important role for antibody for protective immunity, supporting the development of antibody-inducing vaccines against iNTS disease. With candidate O-antigen-based vaccines due to enter clinical trials in the near future, research efforts should focus on understanding the relative contributions of antibody and cell-mediated immunity to protection against iNTS disease in humans.
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Affiliation(s)
| | - Calman A MacLennan
- Jenner Institute, Nuffield Department of Medicine, University of Oxford, Oxford, UK
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13
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Garedew L, Solomon S, Worku Y, Worku H, Gemeda D, Lelissa G, Mamuye Y, Abubeker R, Mihret A, Fentaw S, Worku A, Bahiru M, Erenso G. Diagnosis and Treatment of Human Salmonellosis in Addis Ababa City, Ethiopia. BIOMED RESEARCH INTERNATIONAL 2018; 2018:6406405. [PMID: 29951540 PMCID: PMC5989278 DOI: 10.1155/2018/6406405] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 11/18/2017] [Accepted: 04/19/2018] [Indexed: 11/18/2022]
Abstract
BACKGROUND Diagnosis using reliable tools and treatment following in vitro antimicrobial susceptibility tests are critical to proper addressing of antibiotic-resistant Salmonella infection. METHODOLOGY A cross-sectional study was conducted to assess the practice of diagnosis and treatment of salmonellosis in Addis Ababa. Tube Widal test (for blood samples only), culture, biochemical and carbohydrate fermentation, serotyping, and antimicrobial susceptibility tests were employed for both blood and stool samples. RESULTS Of all the diseases listed in the diagnosis, nontyphoidal (n = 72, 13.71%) and typhoidal (n = 47, 8.95%) salmonellosis were the second and third common diseases. Among the 288 blood samples, almost half were positive for O, H, or both antigens. However, only 1 (0.68%) of the positive blood samples yielded Salmonella isolate during culture. The study demonstrated low specificity (0.68%) and positive predictive value (48.78%) of Widal test. Conversely, the test showed 100% sensitivity and negative predictive values. Salmonella isolates were identified from 7 (7.07%) of 99 stool samples. Two-thirds of salmonellosis suspected patients received antibiotic treatment. However, only half of the confirmed salmonellosis patients were treated with appropriate antibiotics. All of the isolates were susceptible to ciprofloxacin and ceftriaxone but resistant to ampicillin. CONCLUSIONS Majority of the patients who participated in this study were wrongly diagnosed using symptoms, clinical signs, and tube Widal test. Consequently, most of the patients received inappropriate treatment.
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Affiliation(s)
- Legesse Garedew
- St Paul's Hospital Millennium Medical College, Addis Ababa, Ethiopia
| | - Semaria Solomon
- St Paul's Hospital Millennium Medical College, Addis Ababa, Ethiopia
| | - Yoseph Worku
- St Paul's Hospital Millennium Medical College, Addis Ababa, Ethiopia
| | - Hilina Worku
- St Paul's Hospital Millennium Medical College, Addis Ababa, Ethiopia
| | - Debela Gemeda
- St Paul's Hospital Millennium Medical College, Addis Ababa, Ethiopia
| | - Gada Lelissa
- St Paul's Hospital Millennium Medical College, Addis Ababa, Ethiopia
| | - Yeshwondm Mamuye
- St Paul's Hospital Millennium Medical College, Addis Ababa, Ethiopia
| | | | - Amete Mihret
- Ethiopian Public Health Institute, Addis Ababa, Ethiopia
| | - Surafel Fentaw
- Ethiopian Public Health Institute, Addis Ababa, Ethiopia
| | | | | | - Girume Erenso
- St Paul's Hospital Millennium Medical College, Addis Ababa, Ethiopia
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14
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MacLennan CA, Msefula CL, Gondwe EN, Gilchrist JJ, Pensulo P, Mandala WL, Mwimaniwa G, Banda M, Kenny J, Wilson LK, Phiri A, MacLennan JM, Molyneux EM, Molyneux ME, Graham SM. Presentation of life-threatening invasive nontyphoidal Salmonella disease in Malawian children: A prospective observational study. PLoS Negl Trop Dis 2017; 11:e0006027. [PMID: 29216183 PMCID: PMC5745124 DOI: 10.1371/journal.pntd.0006027] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2017] [Revised: 12/27/2017] [Accepted: 10/10/2017] [Indexed: 12/17/2022] Open
Abstract
Nontyphoidal Salmonellae commonly cause invasive disease in African children that is often fatal. The clinical diagnosis of these infections is hampered by the absence of a clear clinical syndrome. Drug resistance means that empirical antibiotic therapy is often ineffective and currently no vaccine is available. The study objective was to identify risk factors for mortality among children presenting to hospital with invasive Salmonella disease in Africa. We conducted a prospective study enrolling consecutive children with microbiologically-confirmed invasive Salmonella disease admitted to Queen Elizabeth Central Hospital, Blantyre, in 2006. Data on clinical presentation, co-morbidities and outcome were used to identify children at risk of inpatient mortality through logistic-regression modeling. Over one calendar year, 263 consecutive children presented with invasive Salmonella disease. Median age was 16 months (range 0-15 years) and 52/256 children (20%; 95%CI 15-25%) died. Nontyphoidal serovars caused 248/263 (94%) of cases. 211/259 (81%) of isolates were multi-drug resistant. 251/263 children presented with bacteremia, 6 with meningitis and 6 with both. Respiratory symptoms were present in 184/240 (77%; 95%CI 71-82%), 123/240 (51%; 95%CI 45-58%) had gastrointestinal symptoms and 101/240 (42%; 95%CI 36-49%) had an overlapping clinical syndrome. Presentation at <7 months (OR 10.0; 95%CI 2.8-35.1), dyspnea (OR 4.2; 95%CI 1.5-12.0) and HIV infection (OR 3.3; 95%CI 1.1-10.2) were independent risk factors for inpatient mortality. Invasive Salmonella disease in Malawi is characterized by high mortality and prevalence of multi-drug resistant isolates, along with non-specific presentation. Young infants, children with dyspnea and HIV-infected children bear a disproportionate burden of the Salmonella-associated mortality in Malawi. Strategies to improve prevention, diagnosis and management of invasive Salmonella disease should be targeted at these children.
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Affiliation(s)
- Calman A. MacLennan
- Jenner Institute, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
- School of Immunity and Infection, College of Medicine and Dental Sciences, University of Birmingham, Birmingham, United Kingdom
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, College of Medicine, University of Malawi, Malawi
| | - Chisomo L. Msefula
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, College of Medicine, University of Malawi, Malawi
- Department of Microbiology, College of Medicine, University of Malawi, Malawi
- Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, United Kingdom
| | - Esther N. Gondwe
- School of Immunity and Infection, College of Medicine and Dental Sciences, University of Birmingham, Birmingham, United Kingdom
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, College of Medicine, University of Malawi, Malawi
- Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, United Kingdom
- Department of Biochemistry, College of Medicine, University of Malawi, Malawi
| | - James J. Gilchrist
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, College of Medicine, University of Malawi, Malawi
- Department of Paediatrics, University of Oxford, United Kingdom
- Wellcome Trust Centre for Human Genetics, University of Oxford, United Kingdom
| | - Paul Pensulo
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, College of Medicine, University of Malawi, Malawi
| | - Wilson L. Mandala
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, College of Medicine, University of Malawi, Malawi
- Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, United Kingdom
- Department of Basic Medical Sciences, College of Medicine, University of Malawi, Blantyre, Malawi
- Academy of Medical Sciences, Malawi University of Science and Technology, Thyolo, Malawi
| | - Grace Mwimaniwa
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, College of Medicine, University of Malawi, Malawi
| | - Meraby Banda
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, College of Medicine, University of Malawi, Malawi
| | - Julia Kenny
- Department of Paediatrics, College of Medicine, University of Malawi, Malawi
- Infectious Diseases and Microbiology Unit, Institute of Child Health, University College London, London, United Kingdom
| | - Lorna K. Wilson
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, College of Medicine, University of Malawi, Malawi
| | - Amos Phiri
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, College of Medicine, University of Malawi, Malawi
| | - Jenny M. MacLennan
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, College of Medicine, University of Malawi, Malawi
- Department of Zoology, University of Oxford, Oxford, United Kingdom
| | | | - Malcolm E. Molyneux
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, College of Medicine, University of Malawi, Malawi
- Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, United Kingdom
- Department of Medicine, College of Medicine, University of Malawi, Malawi
| | - Stephen M. Graham
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, College of Medicine, University of Malawi, Malawi
- Department of Paediatrics, College of Medicine, University of Malawi, Malawi
- Centre for International Child Health, University of Melbourne and Murdoch Children’s Research Institute, Royal Children’s Hospital, Melbourne, Australia
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15
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Abstract
PURPOSE OF REVIEW Typhoidal and nontyphoidal Salmonella enterica serotypes are among the most common bacterial causes of acute febrile illnesses in the developing world. In this review, we discuss new advances in understanding of the burden, diagnostic approaches, treatment and vaccines for invasive Salmonella infections. RECENT FINDINGS Recent estimates of the global burden of typhoidal and nontyphoidal Salmonella not only affirm the importance of these infections but also highlight the paucity of systematic incidence data from many regions. New data from Africa indicate that typhoidal Salmonella may be more common than previously considered. Novel diagnostic techniques for Salmonella include new serologic, molecular and metabolomic approaches, but blood culture - although slow and insensitive - remains the primary means of establishing a diagnosis. Antibiotic resistance, particularly to fluoroquinolones, continues to emerge and threatens to undermine treatment success for these infections. New vaccines for typhoid, including conjugate vaccines with longer duration of immunity than prior vaccines, represent a promising tool for prevention of enteric fever. SUMMARY Invasive Salmonella infections are a major cause of morbidity and mortality worldwide. Increasing antibiotic resistance in Salmonella is concerning, and empiric oral options are being rapidly eroded. Where new effective antimicrobials are lacking, developments in vaccines offer hope for reducing the burden of Salmonella infections globally.
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16
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Haselbeck AH, Panzner U, Im J, Baker S, Meyer CG, Marks F. Current perspectives on invasive nontyphoidal Salmonella disease. Curr Opin Infect Dis 2017; 30:498-503. [PMID: 28731899 PMCID: PMC7680934 DOI: 10.1097/qco.0000000000000398] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
PURPOSE OF REVIEW We searched PubMed for scientific literature published in the past 2 years for relevant information regarding the burden of invasive nontyphoidal Salmonella disease and host factors associated with nontyphoidal Salmonella infection and discuss current knowledge on vaccine development. The following search terms were used: Salmonella, non typhoidal/nontyphoidal, NTS, disease, bloodstream infection, invasive, sepsis/septicaemia/septicemia, bacteraemia/bacteremia, gastroenteritis, incidence, prevalence, morbidity, mortality, case fatality, host/risk factor, vaccination, and prevention/control. RECENT FINDINGS Estimates of the global invasive nontyphoidal Salmonella disease burden have been recently updated; additional data from Africa, Asia, and Latin America are now available. New data bridge various knowledge gaps, particularly with respect to host risk factors and the geographical distribution of iNTS serovars. It has also been observed that Salmonella Typhimurium sequence type 313 is emergent in several African countries. Available data suggest that genetic variation in the sequence type 313 strain has led to increased pathogenicity and human host adaptation. A bivalent efficacious vaccine, targeting Salmonella serovars Typhimurium and Enteritidis, would significantly lower the disease burden in high-risk populations. SUMMARY The mobilization of surveillance networks, especially in Asia and Latin America, may provide missing data regarding the invasive nontyphoidal Salmonella disease burden and their corresponding antimicrobial susceptibility profiles. Efforts and resources should be directed toward invasive nontyphoidal Salmonella disease vaccine development.
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Affiliation(s)
- Andrea H. Haselbeck
- International Vaccine Institute, Epidemiology Unit, Seoul, Republic of Korea
| | - Ursula Panzner
- International Vaccine Institute, Epidemiology Unit, Seoul, Republic of Korea
| | - Justin Im
- International Vaccine Institute, Epidemiology Unit, Seoul, Republic of Korea
| | - Stephen Baker
- Hospital for Tropical Diseases,Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City,Vietnam
- Department of Medicine, University of Cambridge, Cambridge,United Kingdom
| | - Christian G. Meyer
- Institute of Tropical Medicine, Eberhard-Karls University T€ubingen, T€ubingen, Germany and
- Duy Tan University, Da Nang, Vietnam
| | - Florian Marks
- International Vaccine Institute, Epidemiology Unit, Seoul, Republic of Korea
- Department of Medicine, University of Cambridge, Cambridge,United Kingdom
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17
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Abstract
Invasive nontyphoidal Salmonella (NTS) infections in Africa cause an enormous burden of illness. These infections are often devastating, with mortality estimated at 20%, even with appropriate antimicrobial therapy. Two major groups-young children and HIV-infected adults-suffer the great majority of these infections. In children, younger age itself, as well as malaria, malnutrition, and HIV infection, are prominent risk factors. In adults, HIV infection is by far the most important risk factor. The most common serotypes in invasive infections are Salmonella enterica serotypes Typhimurium and Enteritidis. In recent years, a specific strain of Salmonella Typhimurium, multilocus sequence type 313, has caused epidemics of invasive disease. Little is known about risk factors for exposure to NTS, making the design of rational interventions to decrease exposure difficult. Antimicrobial therapy is critically important for treatment of invasive NTS infections. Thus, the emergence and spread of resistance to agents commonly used for treatment of invasive NTS infection, now including third-generation cephalosporins, is an ominous development. Already, many invasive NTS infections are essentially untreatable in many health care facilities in sub-Saharan Africa. Several candidate vaccines are in early development and, if safe and effective, could be promising. Interventions to prevent exposure to NTS (e.g., improved sanitation), to prevent the occurrence of disease if exposure does occur (e.g., vaccination, malaria control), and to prevent severe disease and death in those who become ill (e.g., preserving antimicrobial effectiveness) are all important in reducing the toll of invasive NTS disease in sub-Saharan Africa.
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18
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Keddy KH, Takuva S, Musekiwa A, Puren AJ, Sooka A, Karstaedt A, Klugman KP, Angulo FJ. An association between decreasing incidence of invasive non-typhoidal salmonellosis and increased use of antiretroviral therapy, Gauteng Province, South Africa, 2003-2013. PLoS One 2017; 12:e0173091. [PMID: 28264046 PMCID: PMC5338796 DOI: 10.1371/journal.pone.0173091] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2016] [Accepted: 02/15/2017] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND HIV-infected persons are at increased risk of opportunistic infections, including invasive nontyphoidal Salmonella (iNTS) infections; antiretroviral therapy (ART) reduces this risk. We explored changing iNTS incidence associated with increasing ART availability in South Africa. METHODS Laboratory-based surveillance for iNTS was conducted in Gauteng Province, South Africa, with verification using the National Health Laboratory Service's Central Data Warehouse (CDW), between 2003 and 2013. Isolates were serotyped at the Centre for Enteric Diseases. CDW data on patient numbers obtaining HIV viral load measurements provided estimates of numbers of HIV-infected patients receiving ART. A Poisson regression model was used to measure the changing incidence of iNTS infection from 2003 to 2013. The correlation between the incidence of iNTS and ART use from 2004 to 2013 was determined using Pearson's correlation coefficient. RESULTS From 2003-2013, the incidence of iNTS per 100,000 population per year decreased from 5.0 to 2.2 (p < .001). From 2004 to 2013, the incidence per 100,000 population of HIV viral load testing increased from 75.2 to 3,620.3 (p < .001). The most common serotypes causing invasive disease were Salmonella enterica serovar Typhimurium (Salmonella Typhimurium), and Salmonella Enteritidis: 2,469 (55.4%) and 1,156 (25.9%) of 4,459 isolates serotyped, respectively. A strong negative correlation was observed between decreasing iNTS incidence and increasing ART use from 2004 to 2013 (r = -0.94, p < .001). Similarly, decreasing incidence of invasive Salmonella Typhimurium infection correlated with increasing ART use (r = -0.93, p < .001). Incidence of invasive Salmonella Enteritidis infection increased, however (r = 0.95, p < .001). Between 2003 and 2004, fewer adult men than women presented with iNTS (male-to-female rate ratio 0.73 and 0.89, respectively). This was reversed from 2005 through 2013 (ranging from 1.07 in 2005 to 1.44 in 2013). Adult men accessed ART less (male-to-female rate ratio ranging from 0.61 [2004] to 0.67 [2013]). CONCLUSIONS The incidence of iNTS infections including Salmonella Typhimurium decreased significantly in Gauteng Province in association with increased ART utilization. Adult men accessed ART programs less than women, translating into increasing iNTS incidence in this group. Monitoring iNTS incidence may assist in monitoring the ART program. Increasing incidence of invasive Salmonella Enteritidis infections needs further elucidation.
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Affiliation(s)
- Karen H. Keddy
- Centre for Enteric Diseases, National Institute for Communicable Diseases, National Health Laboratory Service, Johannesburg, South Africa
- Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
- * E-mail:
| | - Simbarashe Takuva
- CARTA Africa, Nairobi, Kenya
- Centre for HIV, National Institute for Communicable Diseases, National Health Laboratory Service, Johannesburg, South Africa
| | - Alfred Musekiwa
- International Emerging Infections Program, South Africa Global Disease Detection Centre, Centers for Disease Control and Prevention, Pretoria, South Africa
| | - Adrian J. Puren
- Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
- Centre for HIV, National Institute for Communicable Diseases, National Health Laboratory Service, Johannesburg, South Africa
| | - Arvinda Sooka
- Centre for Enteric Diseases, National Institute for Communicable Diseases, National Health Laboratory Service, Johannesburg, South Africa
| | - Alan Karstaedt
- Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
- Department of Medicine, Chris Hani Baragwanath Hospital, Johannesburg, South Africa
| | - Keith P. Klugman
- Bill and Melinda Gates Foundation, Seattle, WA, United States of America
| | - Frederick J. Angulo
- Division of Global Health Protection, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA, United States of America
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Keddy KH, Musekiwa A, Sooka A, Karstaedt A, Nana T, Seetharam S, Nchabaleng M, Lekalakala R, Angulo FJ, Klugman KP. Clinical and microbiological features of invasive nontyphoidal Salmonella associated with HIV-infected patients, Gauteng Province, South Africa. Medicine (Baltimore) 2017; 96:e6448. [PMID: 28353576 PMCID: PMC5380260 DOI: 10.1097/md.0000000000006448] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [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
The aim of this study was to define factors associated with HIV-infected versus uninfected patients with invasive nontyphoidal Salmonella (iNTS) and factors associated with mortality, which are inadequately described in Africa.Laboratory-based surveillance for iNTS was undertaken. At selected sentinel sites, clinical data (age, sex, HIV status, severity of illness, and outcome) were collected.Surveillance was conducted in Gauteng, South Africa, from 2003 to 2013. Clinical and microbiological differences between HIV-infected and uninfected patients were defined and risk factors for mortality established.Of 4886 iNTS infections in Gauteng from 2003 to 2013, 3106 (63.5%) were diagnosed at sentinel sites. Among persons with iNTS infections, more HIV-infected persons were aged ≥5 years (χ = 417.6; P < 0.001) and more HIV-infected children were malnourished (χ = 5.8; P = 0.02). Although 760 (30.6%) patients died, mortality decreased between 2003 [97/263 (36.9%)] and 2013 [926/120 (21.7%)]. On univariate analysis, mortality was associated with patients aged 25 to 49 years [odds ratio (OR) = 2.2; 95% confidence interval (CI) = 1.7-2.7; P < 0.001 and ≥50 years (OR = 3.0; 95% CI = 2.2-4.1; P < 0.001) compared with children < 5 years, HIV-infected patients (OR = 2.4; 95% CI = 1.7-3.4; P < 0.001), and severe illness (OR = 5.4; 95% CI = 3.6-8.1; P < 0.001). On multivariate analysis, mortality was associated with patients aged ≥50 years [adjusted OR (AOR) = 3.6, 95% CI = 2.1-6.1, P < 0.001] and severe illness (AOR = 6.3; 95% CI = 3.8-10.5; P < 0.001).Mortality due to iNTS in Gauteng remains high primarily due to disease severity. Interventions must be aimed at predisposing conditions, including HIV, other immune-suppressive conditions, and malignancy.
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Affiliation(s)
- Karen H. Keddy
- Centre for Enteric Diseases, National Institute for Communicable Diseases, National Health Laboratory Service
- Faculty of Health Sciences, University of the Witwatersrand, Johannesburg
| | - Alfred Musekiwa
- International Emerging Infections Program, South Africa Global Disease Detection Centre, Centers for Disease Control and Prevention, Pretoria
| | - Arvinda Sooka
- Centre for Enteric Diseases, National Institute for Communicable Diseases, National Health Laboratory Service
| | - Alan Karstaedt
- Faculty of Health Sciences, University of the Witwatersrand, Johannesburg
- Department of Medicine, Chris Hani Baragwanath Hospital, Johannesburg
| | - Trusha Nana
- Faculty of Health Sciences, University of the Witwatersrand, Johannesburg
- National Health Laboratory Service
| | - Sharona Seetharam
- Faculty of Health Sciences, University of the Witwatersrand, Johannesburg
- National Health Laboratory Service
| | | | - Ruth Lekalakala
- National Health Laboratory Service
- University of Limpopo, Polokwane, South Africa
| | - Frederick J. Angulo
- Division of Global Health Protection, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA
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Levine JA. The Application of Wearable Technologies to Improve Healthcare in the World’s Poorest People. ACTA ACUST UNITED AC 2017. [DOI: 10.4236/ti.2017.82007] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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Abstract
INTRODUCTION Typhoid fever (TF), caused by Salmonella enterica serovar Typhi, is the most common cause of enteric fever, responsible for an estimated 129,000 deaths and more than 11 million cases annually. Although several reviews have provided global and regional TF disease burden estimates, major gaps in our understanding of TF epidemiology remain. Areas covered: We provide an overview of the gaps in current estimates of TF disease burden and offer suggestions for addressing them, so that affected communities can receive the full potential of disease prevention offered by vaccination and water, sanitation, and hygiene interventions. Expert commentary: Current disease burden estimates for TF do not capture cases from certain host populations, nor those with atypical presentations of TF, which may lead to substantial underestimation of TF cases and deaths. These knowledge gaps pose major obstacles to the informed use of current and new generation typhoid vaccines.
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Affiliation(s)
- Stephen K Obaro
- a Department of Pediatrics , University of Nebraska Medical Center , Omaha , NE , USA
| | - Pui-Ying Iroh Tam
- b Department of Pediatrics , University of Minnesota Masonic Children's Hospital , Minneapolis , MN , USA
| | - Eric Daniel Mintz
- c Division of Foodborne, Waterborne and Environmental Diseases , Centers for Disease Control and Prevention , Atlanta , GA , USA
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Lokken KL, Walker GT, Tsolis RM. Disseminated infections with antibiotic-resistant non-typhoidal Salmonella strains: contributions of host and pathogen factors. Pathog Dis 2016; 74:ftw103. [PMID: 27765795 DOI: 10.1093/femspd/ftw103] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/07/2016] [Indexed: 11/14/2022] Open
Abstract
Non-typhoidal Salmonella enterica serovars (NTS) are generally associated with gastroenteritis; however, the very young and elderly, as well as individuals with compromised immunity, are at risk of developing disseminated infection that can manifest as bacteremia or focal infections at systemic sites. Disseminated NTS infections can be fatal and are responsible for over 600 000 deaths annually. Most of these deaths are in sub-Saharan Africa, where multidrug-resistant NTS clones are currently circulating in a population with a high proportion of individuals that are susceptible to disseminated disease. This review considers how genome degradation observed in African NTS isolates has resulted in phenotypic differences in traits related to environmental persistence and host-pathogen interactions. Further, it discusses host mechanisms promoting susceptibility to invasive infection with NTS in individuals with immunocompromising conditions. We conclude that mechanistic knowledge of how risk factors compromise immunity to disseminated NTS infection will be important for the design of interventions to protect against systemic disease.
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Affiliation(s)
- Kristen L Lokken
- Medical Microbiology and Immunology, University of California, One Shields Avenue, Davis, CA 95616, USA
| | - Gregory T Walker
- Medical Microbiology and Immunology, University of California, One Shields Avenue, Davis, CA 95616, USA
| | - Renée M Tsolis
- Medical Microbiology and Immunology, University of California, One Shields Avenue, Davis, CA 95616, USA
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