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Falay D, Hardy L, Bonebe E, Mattheus W, Ngbonda D, Lunguya O, Jacobs J. Intestinal carriage of invasive non-typhoidal Salmonella among household members of children with Salmonella bloodstream infection, Kisangani, DR Congo. Front Microbiol 2023; 14:1241961. [PMID: 37901802 PMCID: PMC10602682 DOI: 10.3389/fmicb.2023.1241961] [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: 06/18/2023] [Accepted: 09/18/2023] [Indexed: 10/31/2023] Open
Abstract
Introduction Invasive non-typhoidal Salmonella (iNTS), mainly Salmonella Typhimurium and Salmonella Enteritidis, causes a severe burden in sub-Saharan Africa; however, its reservoir (animal or environmental) is unclear. The present study assessed healthy household members of index patients for intestinal carriage of Salmonella. Methods Index patients were admitted to the University Hospital of Kisangani (DR Congo), and Salmonella was grown from blood cultures. Household members were asked to provide three stool samples for culture for Salmonella. Salmonella Typhimurium and S. Enteritidis isolates from index patients, and household members were assessed for genetic relatedness using the multiple-locus variable number of tandem repeat analysis (MLVA), and the multilocus sequence type (ST) was determined by whole genome sequencing. Results Between May 2016 and January 2020, 22 households were visited. The index patient serotypes were Typhimurium, Enteritidis, Typhi, and Paratyphi C; II:42:r:-; and I:7:y:- (n = 8, 7, 5, and each 1, respectively). The median (range) delay between the index patient and household sampling was 25 days (2 days to 7.3 months); 203 household members provided at least one stool sample. In all, 15 (7.3%) Salmonella carriers were found in nine of 22 households. For one index patient, the household comprised S. Typhimurium in four household members, including the index patient, sampled 27 days after bloodstream infection; the MLVA types of these five isolates were similar. They belonged to ST313 lineage 2 and were closely related [0-1 allelic distance (AD) among the stool isolates and eight AD with the blood culture isolate]. In another household, the stool culture of the index patient (obtained 67 days after bloodstream infection) grew S. Enteritidis of the same MLVA type; both isolates belonged to the ST11 Central/Eastern African clade and were closely related (three AD). Discussion The present study provides evidence of household clustering of S. Typhimurium ST313 and intestinal carriage of iNTS several weeks after bloodstream infection.
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Affiliation(s)
- Dadi Falay
- Department of Pediatrics, University Hospital of Kisangani, Kisangani, Democratic Republic of Congo
- Department of Clinical Sciences, Institute of Tropical Medicine, Antwerp, Belgium
- Department of Microbiology, Immunology and Transplantation, KU Leuven, Leuven, Belgium
| | - Liselotte Hardy
- Department of Microbiology, Immunology and Transplantation, KU Leuven, Leuven, Belgium
| | - Edmonde Bonebe
- Department of Microbiology, National Institute for Biomedical Research, Kinshasa, Democratic Republic of Congo
| | - Wesley Mattheus
- Division of Human Bacterial Diseases, Sciensano, Uccle, Belgium
| | - Dauly Ngbonda
- Department of Pediatrics, University Hospital of Kisangani, Kisangani, Democratic Republic of Congo
| | - Octavie Lunguya
- Department of Microbiology, National Institute for Biomedical Research, Kinshasa, Democratic Republic of Congo
- Department of Microbiology, University Teaching Hospital of Kinshasa, Kinshasa, Democratic Republic of Congo
| | - Jan Jacobs
- Department of Clinical Sciences, Institute of Tropical Medicine, Antwerp, Belgium
- Department of Microbiology, Immunology and Transplantation, KU Leuven, Leuven, Belgium
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Swarthout JM, Chan EMG, Garcia D, Nadimpalli ML, Pickering AJ. Human Colonization with Antibiotic-Resistant Bacteria from Nonoccupational Exposure to Domesticated Animals in Low- and Middle-Income Countries: A Critical Review. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:14875-14890. [PMID: 35947446 DOI: 10.1021/acs.est.2c01494] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Data on community-acquired antibiotic-resistant bacterial infections are particularly sparse in low- and middle-income countries (LMICs). Limited surveillance and oversight of antibiotic use in food-producing animals, inadequate access to safe drinking water, and insufficient sanitation and hygiene infrastructure in LMICs could exacerbate the risk of zoonotic antibiotic resistance transmission. This critical review compiles evidence of zoonotic exchange of antibiotic-resistant bacteria (ARB) or antibiotic resistance genes (ARGs) within households and backyard farms in LMICs, as well as assesses transmission mechanisms, risk factors, and environmental transmission pathways. Overall, substantial evidence exists for exchange of antibiotic resistance between domesticated animals and in-contact humans. Whole bacteria transmission and horizontal gene transfer between humans and animals were demonstrated within and between households and backyard farms. Further, we identified water, soil, and animal food products as environmental transmission pathways for exchange of ARB and ARGs between animals and humans, although directionality of transmission is poorly understood. Herein we propose study designs, methods, and topical considerations for priority incorporation into future One Health research to inform effective interventions and policies to disrupt zoonotic antibiotic resistance exchange in low-income communities.
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Affiliation(s)
- Jenna M Swarthout
- Department of Civil and Environmental Engineering, Tufts University, Medford, Massachusetts 02155, United States
| | - Elana M G Chan
- Department of Civil and Environmental Engineering, Tufts University, Medford, Massachusetts 02155, United States
| | - Denise Garcia
- Department of Civil and Environmental Engineering, University of California, Berkeley, Berkeley, California 94720, United States
| | - Maya L Nadimpalli
- Department of Civil and Environmental Engineering, Tufts University, Medford, Massachusetts 02155, United States
- Stuart B. Levy Center for Integrated Management of Antimicrobial Resistance, Tufts University, Boston, Massachusetts 02111, United States
| | - Amy J Pickering
- Department of Civil and Environmental Engineering, Tufts University, Medford, Massachusetts 02155, United States
- Department of Civil and Environmental Engineering, University of California, Berkeley, Berkeley, California 94720, United States
- Stuart B. Levy Center for Integrated Management of Antimicrobial Resistance, Tufts University, Boston, Massachusetts 02111, United States
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Chen D, Mechlowitz K, Li X, Schaefer N, Havelaar AH, McKune SL. Benefits and Risks of Smallholder Livestock Production on Child Nutrition in Low- and Middle-Income Countries. Front Nutr 2021; 8:751686. [PMID: 34778344 PMCID: PMC8579112 DOI: 10.3389/fnut.2021.751686] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2021] [Accepted: 09/29/2021] [Indexed: 12/12/2022] Open
Abstract
Livestock production may improve nutritional outcomes of pregnant women and children by increasing household income, availability of nutrient-dense foods, and women's empowerment. Nevertheless, the relationship is complex, and the nutritional status of children may be impaired by presence of or proximity to livestock and their pathogens. In this paper, we review the benefits and risks of livestock production on child nutrition. Evidence supports the nutritional benefits of livestock farming through income, production, and women's empowerment. Increasing animal source food consumption requires a combination of efforts, including improved animal management so that herd size is adequate to meet household income needs and consumption and addressing sociocultural and gendered norms. Evidence supports the inclusion of behavior change communication strategies into livestock production interventions to facilitate the sustainability of nutritional benefits over time, particularly interventions that engage women and foster dimensions of women's empowerment. In evaluating the risks of livestock production, evidence indicates that a broad range of enteric pathogens may chronically infect the intestines of children and, in combination with dietary deficits, may cause environmental enteric dysfunction (EED), a chronic inflammation of the gut. Some of the most important pathogens associated with EED are zoonotic in nature with livestock as their main reservoir. Very few studies have aimed to understand which livestock species contribute most to colonization with these pathogens, or how to reduce transmission. Control at the point of exposure has been investigated in a few studies, but much less effort has been spent on improving animal husbandry practices, which may have additional benefits. There is an urgent need for dedicated and long-term research to understand which livestock species contribute most to exposure of young children to zoonotic enteric pathogens, to test the potential of a wide range of intervention methods, to assess their effectiveness in randomized trials, and to assure their broad adaptation and sustainability. This review highlights the benefits and risks of livestock production on child nutrition. In addition to identifying research gaps, findings support inclusion of poor gut health as an immediate determinant of child undernutrition, expanding the established UNICEF framework which includes only inadequate diet and disease.
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Affiliation(s)
- Dehao Chen
- Department of Environmental and Global Health, College of Public Health and Health Professions, University of Florida, Gainesville, FL, United States
- Emerging Pathogens Institute, University of Florida, Gainesville, FL, United States
| | - Karah Mechlowitz
- Department of Social and Behavioral Sciences, College of Public Health and Health Professions, University of Florida, Gainesville, FL, United States
| | - Xiaolong Li
- Department of Environmental and Global Health, College of Public Health and Health Professions, University of Florida, Gainesville, FL, United States
- Emerging Pathogens Institute, University of Florida, Gainesville, FL, United States
| | - Nancy Schaefer
- Health Science Center Libraries, University of Florida, Gainesville, FL, United States
| | - Arie H. Havelaar
- Emerging Pathogens Institute, University of Florida, Gainesville, FL, United States
- Department of Animal Sciences, Institute of Food and Agricultural Sciences, University of Florida, Gainesville, FL, United States
- Institute for Sustainable Food Systems, University of Florida, Gainesville, FL, United States
| | - Sarah L. McKune
- Department of Environmental and Global Health, College of Public Health and Health Professions, University of Florida, Gainesville, FL, United States
- Center for African Studies, University of Florida, Gainesville, FL, United States
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4
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Qu Z, McMahon BH, Perkins DJ, Hyman JM. Staged progression epidemic models for the transmission of invasive nontyphoidal Salmonella (iNTS) with treatment. MATHEMATICAL BIOSCIENCES AND ENGINEERING : MBE 2021; 18:1529-1549. [PMID: 33757197 PMCID: PMC11064643 DOI: 10.3934/mbe.2021079] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
We develop and analyze a stage-progression compartmental model to study the emerging invasive nontyphoidal Salmonella (iNTS) epidemic in sub-Saharan Africa. iNTS bloodstream infections are often fatal, and the diverse and non-specific clinical features of iNTS make it difficult to diagnose. We focus our study on identifying approaches that can reduce the incidence of new infections. In sub-Saharan Africa, transmission and mortality are correlated with the ongoing HIV epidemic and severe malnutrition. We use our model to quantify the impact that increasing antiretroviral therapy (ART) for HIV infected adults and reducing malnutrition in children would have on mortality from iNTS in the population. We consider immunocompromised subpopulations in the region with major risk factors for mortality, such as malaria and malnutrition among children and HIV infection and ART coverage in both children and adults. We parameterize the progression rates between infection stages using the branching probabilities and estimated time spent at each stage. We interpret the basic reproduction number R0 as the total contribution from an infinite infection loop produced by the asymptomatic carriers in the infection chain. The results indicate that the asymptomatic HIV+ adults without ART serve as the driving force of infection for the iNTS epidemic. We conclude that the worst disease outcome is among the pediatric population, which has the highest infection rates and death counts. Our sensitivity analysis indicates that the most effective strategies to reduce iNTS mortality in the studied population are to improve the ART coverage among high-risk HIV+ adults and reduce malnutrition among children.
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Affiliation(s)
- Zhuolin Qu
- Department of Mathematics, University of Texas at San Antonio, San Antonio 78202, TX, USA
| | - Benjamin H. McMahon
- Theoretical Biology and Biophysics, Los Alamos National Laboratory, Los Alamos, NM, USA
| | - Douglas J. Perkins
- University of New Mexico, Center for Global Health, Department of Internal Medicine, NM, USA
- University of New Mexico-Kenya Global Health Programs, Kisumu and Siaya, Kenya
| | - James M. Hyman
- Department of Mathematics, Tulane University, New Orleans 70112, LA, USA
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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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Piccini G, Montomoli E. Pathogenic signature of invasive non-typhoidal Salmonella in Africa: implications for vaccine development. Hum Vaccin Immunother 2020; 16:2056-2071. [PMID: 32692622 PMCID: PMC7553687 DOI: 10.1080/21645515.2020.1785791] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
Invasive non-typhoidal Salmonella (iNTS) infections are a leading cause of bacteremia in Sub-Saharan Africa (sSA), thereby representing a major public health threat. Salmonella Typhimurium clade ST313 and Salmonella Enteriditis lineages associated with Western and Central/Eastern Africa are among the iNTS serovars which are of the greatest concern due to their case-fatality rate, especially in children and in the immunocompromised population. Identification of pathogen-associated features and host susceptibility factors that increase the risk for invasive non-typhoidal salmonellosis would be instrumental for the design of targeted prevention strategies, which are urgently needed given the increasing spread of multidrug-resistant iNTS in Africa. This review summarizes current knowledge of bacterial traits and host immune responses associated with iNTS infections in sSA, then discusses how this knowledge can guide vaccine development while providing a summary of vaccine candidates in preclinical and early clinical development.
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Affiliation(s)
| | - Emanuele Montomoli
- VisMederi srl , Siena, Italy.,Department of Molecular and Developmental Medicine, University of Siena , Siena, Italy
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Mbae C, Mwangi M, Gitau N, Irungu T, Muendo F, Wakio Z, Wambui R, Kavai S, Onsare R, Wairimu C, Ngetich R, Njeru F, Van Puyvelde S, Clemens J, Dougan G, Kariuki S. Factors associated with occurrence of salmonellosis among children living in Mukuru slum, an urban informal settlement in Kenya. BMC Infect Dis 2020; 20:422. [PMID: 32552753 PMCID: PMC7302364 DOI: 10.1186/s12879-020-05134-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Accepted: 06/01/2020] [Indexed: 12/19/2022] Open
Abstract
Background In Kenya, typhoid fever and invasive non-typhoidal salmonellosis present a huge burden of disease, especially in poor-resource settings where clean water supply and sanitation conditions are inadequate. The epidemiology of both diseases is poorly understood in terms of severity and risk factors. The aim of the study was to determine the disease burden and spatial distribution of salmonellosis, as well as socioeconomic and environmental risk factors for these infections, in a large informal settlement near the city of Nairobi, from 2013 to 2017. Methods Initially, a house-to-house baseline census of 150,000 population in Mukuru informal settlement was carried out and relevant socioeconomic, demographic, and healthcare utilization information was collected using structured questionnaires. Salmonella bacteria were cultured from the blood and faeces of children < 16 years of age who reported at three outpatient facilities with fever alone or fever and diarrhea. Tests of association between specific Salmonella serotypes and risk factors were conducted using Pearson Chi-Square (χ2) test. Results A total of 16,236 children were recruited into the study. The prevalence of bloodstream infections by Non-Typhoidal Salmonella (NTS), consisting of Salmonella Typhimurium/ Enteriditis, was 1.3%; Salmonella Typhi was 1.4%, and this was highest among children < 16 years of age. Occurrence of Salmonella Typhimurium/ Enteriditis was not significantly associated with rearing any domestic animals. Rearing chicken was significantly associated with high prevalence of S. Typhi (2.1%; p = 0.011). The proportion of children infected with Salmonella Typhimurium/ Enteriditis was significantly higher in households that used water pots as water storage containers compared to using water directly from the tap (0.6%). Use of pit latrines and open defecation were significant risk factors for S. Typhi infection (1.6%; p = 0.048). The proportion of Salmonella Typhimurium/ Enteriditis among children eating street food 4 or more times per week was higher compared to 1 to 2 times/week on average (1.1%; p = 0.032). Conclusion Typhoidal and NTS are important causes of illness in children in Mukuru informal settlement, especially among children less than 16 years of age. Improving Water, Sanitation and Hygiene (WASH) including boiling water, breastfeeding, hand washing practices, and avoiding animal contact in domestic settings could contribute to reducing the risk of transmission of Salmonella disease from contaminated environments.
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Affiliation(s)
- Cecilia Mbae
- Centre for Microbiology Research, Kenya Medical Research Institute, Off Mbagathi Road, PO Box 54840-00200, Nairobi, Kenya.
| | - Moses Mwangi
- Centre for Public Health Research, Kenya Medical Research Institute, Nairobi, Kenya
| | - Naomi Gitau
- Centre for Microbiology Research, Kenya Medical Research Institute, Off Mbagathi Road, PO Box 54840-00200, Nairobi, Kenya
| | - Tabitha Irungu
- Centre for Microbiology Research, Kenya Medical Research Institute, Off Mbagathi Road, PO Box 54840-00200, Nairobi, Kenya
| | - Fidelis Muendo
- Centre for Public Health Research, Kenya Medical Research Institute, Nairobi, Kenya
| | - Zilla Wakio
- Centre for Microbiology Research, Kenya Medical Research Institute, Off Mbagathi Road, PO Box 54840-00200, Nairobi, Kenya
| | - Ruth Wambui
- Centre for Microbiology Research, Kenya Medical Research Institute, Off Mbagathi Road, PO Box 54840-00200, Nairobi, Kenya
| | - Susan Kavai
- Centre for Microbiology Research, Kenya Medical Research Institute, Off Mbagathi Road, PO Box 54840-00200, Nairobi, Kenya
| | - Robert Onsare
- Centre for Microbiology Research, Kenya Medical Research Institute, Off Mbagathi Road, PO Box 54840-00200, Nairobi, Kenya
| | - Celestine Wairimu
- Centre for Microbiology Research, Kenya Medical Research Institute, Off Mbagathi Road, PO Box 54840-00200, Nairobi, Kenya
| | - Ronald Ngetich
- Centre for Microbiology Research, Kenya Medical Research Institute, Off Mbagathi Road, PO Box 54840-00200, Nairobi, Kenya
| | - Frida Njeru
- Centre for Microbiology Research, Kenya Medical Research Institute, Off Mbagathi Road, PO Box 54840-00200, Nairobi, Kenya
| | - Sandra Van Puyvelde
- Department of Medicine, University of Cambridge, Cambridge, UK.,Department of Biomedical Sciences, Institute of Tropical Medicine, Antwerp, Belgium.,Laboratory of Medical Microbiology, Vaccine & Infectious Disease Institute, Universiteit Antwerpen, Antwerp, Belgium
| | - John Clemens
- International Centre for Diarrhoeal Disease Research, Dhaka, Bangladesh
| | - Gordon Dougan
- Department of Medicine, University of Cambridge, Cambridge, UK
| | - Samuel Kariuki
- Centre for Microbiology Research, Kenya Medical Research Institute, Off Mbagathi Road, PO Box 54840-00200, Nairobi, Kenya.,Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, UK
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Okafor UC, Okafor SC, Ogugua AJ. Occurrence of multidrug-resistant Salmonella in cattle carcass and contact surfaces in Kwata slaughterhouse, Awka, Anambra State, Nigeria. INTERNATIONAL JOURNAL OF ONE HEALTH 2020. [DOI: 10.14202/ijoh.2020.49-55] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Background and Aim: Contamination of meat with Salmonella could result in food-borne disease outbreaks among the consumers. However, there is a dearth of data assessing the presence of Salmonella in beef in Anambra State. Therefore, this study determined the prevalence and antimicrobial susceptibility of Salmonella in beef and slaughter/processing facilities in Kwata slaughterhouse.
Materials and Methods: Swab samples (200) randomly collected were cultured for the isolation of Salmonella and the isolates subjected to antimicrobial susceptibility test. Data obtained were analyzed using t-test and analysis of variance with p< 0.05 considered statistically significant.
Results: Of the 200 samples cultured, 33.5% (67/200) yielded Salmonella isolates. The mean Salmonella load (colony-forming unit [CFU]/cm2) for different contact surfaces (before and after contact with carcasses) was as follows: Slaughter floor, 1.1×1010±1.1×106a and 1.0×1010±1.1×106b; display table, 1.1×1010±11.1×106a and 1.0×1010±1.1×106b; washing bucket 1.01×1010±1.0×106a and 0.8×1010±0.1×106b; knife, 1.1×1010±1.10×106a and 1×1010±1.0×106b; boot, 1.1×1010±1.0×106a and 1.0×1010±1.10×106b; file, 1.1×1010±1.0×106a and 1.0×1010±0.1×106b; and wheelbarrow, 1.1×1010±1.0×106a and 1.01×1010±0.11×106b. Salmonella counts decreased significantly (p<0.05) in the presented order from slaughter floor to wheelbarrow after contact with carcasses. On the other hand, there was a significant (p<0.05) increase in washing water Salmonella counts before and after (0.7×1010±0.10×106a and 1.0×1010±1.0×106b CFU/100 ml) carcasses wash. To each of the antimicrobials tested, the percentage of the 67 isolates found resistant was as follows: ciprofloxacin, 25.4%; ofloxacin, 27%; ceftriaxone, 35.8%; amoxicillin/clavulanic acid, 88.1%; chloramphenicol, 59.7%; gentamicin, 34.3%; streptomycin, 49.3%; nalidixic acid, 49.3%; trimethoprim/sulfamethoxazole, 76%; nitrofurantoin, 89.6%; and ampicillin, 100%.
Conclusion: Antimicrobial-resistant Salmonella were isolated from beef and slaughter/processing facilities in Anambra State. This underscores the need for a coordinated one health approach for the improvement of hygienic standard during slaughter/processing in the slaughterhouse surveyed, to limit meat contamination and hence safeguard human health.
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Affiliation(s)
- Uju Catherine Okafor
- Department of Veterinary Public Health and Preventive Medicine, University of Nigeria, Nsukka, Nigeria
| | - Simeon Chibuko Okafor
- Department of Veterinary Pathology and Microbiology, University of Nigeria, Nsukka, Nigeria
| | - Akwoba Joseph Ogugua
- Department of Veterinary Public Health and Preventive Medicine, University of Nigeria, Nsukka, Nigeria
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9
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Manore C, Graham T, Carr A, Feryn A, Jakhar S, Mukundan H, Highlander HC. Modeling and Cost Benefit Analysis to Guide Deployment of POC Diagnostics for Non-typhoidal Salmonella Infections with Antimicrobial Resistance. Sci Rep 2019; 9:11245. [PMID: 31375759 PMCID: PMC6677775 DOI: 10.1038/s41598-019-47359-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2018] [Accepted: 07/05/2019] [Indexed: 12/03/2022] Open
Abstract
Invasive non-typhoidal Salmonella (NTS) is among the leading causes of blood stream infections in sub-Saharan Africa and other developing regions, especially among pediatric populations. Invasive NTS can be difficult to treat and have high case-fatality rates, in part due to emergence of strains resistant to broad-spectrum antibiotics. Furthermore, improper treatment contributes to increased antibiotic resistance and death. Point of care (POC) diagnostic tests that rapidly identify invasive NTS infection, and differentiate between resistant and non-resistant strains, may greatly improve patient outcomes and decrease resistance at the community level. Here we present for the first time a model for NTS dynamics in high risk populations that can analyze the potential advantages and disadvantages of four strategies involving POC diagnostic deployment, and the resulting impact on antimicrobial treatment for patients. Our analysis strongly supports the use of POC diagnostics coupled with targeted antibiotic use for patients upon arrival in the clinic for optimal patient and public health outcomes. We show that even the use of imperfect POC diagnostics can significantly reduce total costs and number of deaths, provided that the diagnostic gives results quickly enough that patients are likely to return or stay to receive targeted treatment.
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Affiliation(s)
- Carrie Manore
- Los Alamos National Laboratory, Theoretical Biology and Biophysics, Los Alamos, 87544, USA.
| | - Todd Graham
- University of Portland, Mathematics Department, Portland, 97203, USA
| | - Alexa Carr
- University of Portland, Mathematics Department, Portland, 97203, USA
| | - Alicia Feryn
- University of Portland, Mathematics Department, Portland, 97203, USA
| | - Shailja Jakhar
- Los Alamos National Laboratory, Chemistry, Los Alamos, 87544, USA
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10
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Emergence of dominant multidrug-resistant bacterial clades: Lessons from history and whole-genome sequencing. Proc Natl Acad Sci U S A 2019; 115:12872-12877. [PMID: 30559200 DOI: 10.1073/pnas.1717162115] [Citation(s) in RCA: 54] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Antibiotic resistance in bacteria has emerged as a global challenge over the past 90 years, compromising our ability to effectively treat infections. There has been a dramatic increase in antibiotic resistance-associated determinants in bacterial populations, driven by the mobility and infectious nature of such determinants. Bacterial genome flexibility and antibiotic-driven selection are at the root of the problem. Genome evolution and the emergence of highly successful multidrug-resistant clades in different pathogens have made this a global challenge. Here, we describe some of the factors driving the origin, evolution, and spread of the antibiotic resistance genotype.
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11
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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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12
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New Variant of Multidrug-Resistant Salmonella enterica Serovar Typhimurium Associated with Invasive Disease in Immunocompromised Patients in Vietnam. mBio 2018; 9:mBio.01056-18. [PMID: 30181247 PMCID: PMC6123440 DOI: 10.1128/mbio.01056-18] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Salmonella Typhimurium is a major diarrheal pathogen and associated with invasive nontyphoid Salmonella (iNTS) disease in vulnerable populations. We present the first characterization of iNTS organisms in Southeast Asia and describe a different evolutionary trajectory from that of organisms causing iNTS in sub-Saharan Africa. In Vietnam, the globally distributed monophasic variant of Salmonella Typhimurium, the serovar I:4,[5],12:i:− ST34 clone, has reacquired a phase 2 flagellum and gained a multidrug-resistant plasmid to become associated with iNTS disease in HIV-infected patients. We document distinct communities of S. Typhimurium and I:4,[5],12:i:− in animals and humans in Vietnam, despite the greater mixing of these host populations here. These data highlight the importance of whole-genome sequencing surveillance in a One Health context in understanding the evolution and spread of resistant bacterial infections. Nontyphoidal Salmonella (NTS), particularly Salmonella enterica serovar Typhimurium, is among the leading etiologic agents of bacterial enterocolitis globally and a well-characterized cause of invasive disease (iNTS) in sub-Saharan Africa. In contrast, S. Typhimurium is poorly defined in Southeast Asia, a known hot spot for zoonotic disease with a recently described burden of iNTS disease. Here, we aimed to add insight into the epidemiology and potential impact of zoonotic transfer and antimicrobial resistance (AMR) in S. Typhimurium associated with iNTS and enterocolitis in Vietnam. We performed whole-genome sequencing and phylogenetic reconstruction on 85 human (enterocolitis, carriage, and iNTS) and 113 animal S. Typhimurium isolates isolated in Vietnam. We found limited evidence for the zoonotic transmission of S. Typhimurium. However, we describe a chain of events where a pandemic monophasic variant of S. Typhimurium (serovar I:4,[5],12:i:− sequence type 34 [ST34]) has been introduced into Vietnam, reacquired a phase 2 flagellum, and acquired an IncHI2 multidrug-resistant plasmid. Notably, these novel biphasic ST34 S. Typhimurium variants were significantly associated with iNTS in Vietnamese HIV-infected patients. Our study represents the first characterization of novel iNTS organisms isolated outside sub-Saharan Africa and outlines a new pathway for the emergence of alternative Salmonella variants into susceptible human populations.
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13
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Branchu P, Bawn M, Kingsley RA. Genome Variation and Molecular Epidemiology of Salmonella enterica Serovar Typhimurium Pathovariants. Infect Immun 2018; 86:e00079-18. [PMID: 29784861 PMCID: PMC6056856 DOI: 10.1128/iai.00079-18] [Citation(s) in RCA: 69] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Salmonella enterica serovar Typhimurium is one of approximately 2,500 distinct serovars of the genus Salmonella but is exceptional in its wide distribution in the environment, livestock, and wild animals. S Typhimurium causes a large proportion of nontyphoidal Salmonella (NTS) infections, accounting for a quarter of infections, second only to S. enterica serovar Enteritidis in incidence. S Typhimurium was once considered the archetypal broad-host-range Salmonella serovar due to its wide distribution in livestock and wild animals, and much of what we know of the interaction of Salmonella with the host comes from research using a small number of laboratory strains of the serovar (LT2, SL1344, and ATCC 14028). But it has become clear that these strains do not reflect the genotypic or phenotypic diversity of S Typhimurium. Here, we review the epidemiological record of S Typhimurium and studies of the host-pathogen interactions of diverse strains of S Typhimurium. We present the concept of distinct pathovariants of S Typhimurium that exhibit diversity of host range, distribution in the environment, pathogenicity, and risk to food safety. We review recent evidence from whole-genome sequencing that has revealed the extent of genomic diversity of S Typhimurium pathovariants, the genomic basis of differences in the level of risk to human and animal health, and the molecular epidemiology of prominent strains. An improved understanding of the impact of genome variation of bacterial pathogens on pathogen-host and pathogen-environment interactions has the potential to improve quantitative risk assessment and reveal how new pathogens evolve.
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Affiliation(s)
- Priscilla Branchu
- Quadram Institute Bioscience, Norwich Research Park, Colney, Norwich, United Kingdom
| | - Matt Bawn
- Quadram Institute Bioscience, Norwich Research Park, Colney, Norwich, United Kingdom
- Earlham Institute, Norwich Research Park, Colney, Norwich, United Kingdom
| | - Robert A Kingsley
- Quadram Institute Bioscience, Norwich Research Park, Colney, Norwich, United Kingdom
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14
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MacKenzie KD, Palmer MB, Köster WL, White AP. Examining the Link between Biofilm Formation and the Ability of Pathogenic Salmonella Strains to Colonize Multiple Host Species. Front Vet Sci 2017; 4:138. [PMID: 29159172 PMCID: PMC5581909 DOI: 10.3389/fvets.2017.00138] [Citation(s) in RCA: 59] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2017] [Accepted: 08/09/2017] [Indexed: 12/11/2022] Open
Abstract
Salmonella are important pathogens worldwide and a predominant number of human infections are zoonotic in nature. The ability of strains to form biofilms, which is a multicellular behavior characterized by the aggregation of cells, is predicted to be a conserved strategy for increased persistence and survival. It may also contribute to the increasing number of infections caused by ingestion of contaminated fruits and vegetables. There is a correlation between biofilm formation and the ability of strains to colonize and replicate within the intestines of multiple host species. These strains predominantly cause localized gastroenteritis infections in humans. In contrast, there are salmonellae that cause systemic, disseminated infections in a select few host species; these “invasive” strains have a narrowed host range, and most are unable to form biofilms. This includes host-restricted Salmonella serovar Typhi, which are only able to infect humans, and atypical gastroenteritis strains associated with the opportunistic infection of immunocompromised patients. From the perspective of transmission, biofilm formation is advantageous for ensuring pathogen survival in the environment. However, from an infection point of view, biofilm formation may be an anti-virulence trait. We do not know if the capacity to form biofilms prevents a strain from accessing the systemic compartments within the host or if loss of the biofilm phenotype reflects a change in a strain’s interaction with the host. In this review, we examine the connections between biofilm formation, Salmonella disease states, degrees of host adaptation, and how this might relate to different transmission patterns. A better understanding of the dynamic lifecycle of Salmonella will allow us to reduce the burden of livestock and human infections caused by these important pathogens.
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Affiliation(s)
- Keith D MacKenzie
- Vaccine and Infectious Disease Organization-International Vaccine Centre, Saskatoon, SK, Canada.,Department of Microbiology and Immunology, University of Saskatchewan, Saskatoon, SK, Canada
| | - Melissa B Palmer
- Vaccine and Infectious Disease Organization-International Vaccine Centre, Saskatoon, SK, Canada.,Department of Microbiology and Immunology, University of Saskatchewan, Saskatoon, SK, Canada
| | - Wolfgang L Köster
- Vaccine and Infectious Disease Organization-International Vaccine Centre, Saskatoon, SK, Canada.,Department of Veterinary Microbiology, University of Saskatchewan, Saskatoon, SK, Canada
| | - Aaron P White
- Vaccine and Infectious Disease Organization-International Vaccine Centre, Saskatoon, SK, Canada.,Department of Microbiology and Immunology, University of Saskatchewan, Saskatoon, SK, Canada
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15
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Nyabundi D, Onkoba N, Kimathi R, Nyachieo A, Juma G, Kinyanjui P, Kamau J. Molecular characterization and antibiotic resistance profiles of Salmonella isolated from fecal matter of domestic animals and animal products in Nairobi. TROPICAL DISEASES TRAVEL MEDICINE AND VACCINES 2017; 3:2. [PMID: 28883972 PMCID: PMC5530968 DOI: 10.1186/s40794-016-0045-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/24/2016] [Accepted: 12/18/2016] [Indexed: 11/26/2022]
Abstract
Background Salmonella has significant public health implications causing food borne and zoonotic diseases in humans. Treatment of infections due to Salmonella is becoming difficult due to emergence of drug resistant strains. There is therefore need to characterize the circulating non-typhoidal Salmonella (NTS) serovars in domestic animals and animal products in Kenya as well as determine their antibiotic resistance profiles. Methods A total of 740 fecal samples were collected from cows (n = 150), pigs (n = 182), chicken (n = 191) and chicken eggs (n = 217) from various markets and abattoirs in Nairobi. The prevalence of NTS serovars using culture techniques and biochemical tests, antimicrobial sensitivity testing using disc diffusion method of the commonly prescribed antibiotics and phylogenetic relationships using 16S rRNA were determined. Results The results showed that the overall prevalence of Salmonella was 3.8, 3.6, 5.9 and 2.6% for pigs, chicken, eggs and cows respectively. Two serovars were isolated S. Typhimurium (85%) and S. Enteritidis (15%) and these two serovars formed distinct clades on the phylogenetic tree. Forty percent of the isolates were resistant to one or more antibiotics. Conclusion The isolation of Salmonella Typhimurium and Salmonella Enteritidis that are resistant to commonly used antibiotics from seemingly healthy animals and animal products poses a significant public health threat. This points to the need for regular surveillance to be carried out and the chain of transmission should be viewed to ascertain sources of contamination.
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Affiliation(s)
- Diana Nyabundi
- Department of Biochemistry, School of Medicine, University of Nairobi, P.O. Box 30197-00100, Nairobi, Kenya
| | - Nyamongo Onkoba
- Institute of Primate Research, P.O. Box 24481-00502, Karen, Nairobi, Kenya
| | - Rinter Kimathi
- Department of Biochemistry, School of Medicine, University of Nairobi, P.O. Box 30197-00100, Nairobi, Kenya
| | - Atunga Nyachieo
- Department of Biochemistry, School of Medicine, University of Nairobi, P.O. Box 30197-00100, Nairobi, Kenya.,Institute of Primate Research, P.O. Box 24481-00502, Karen, Nairobi, Kenya
| | - Gerald Juma
- Department of Biochemistry, School of Medicine, University of Nairobi, P.O. Box 30197-00100, Nairobi, Kenya
| | - Peter Kinyanjui
- Department of Biochemistry, School of Medicine, University of Nairobi, P.O. Box 30197-00100, Nairobi, Kenya
| | - Joseph Kamau
- Department of Biochemistry, School of Medicine, University of Nairobi, P.O. Box 30197-00100, Nairobi, Kenya.,Institute of Primate Research, P.O. Box 24481-00502, Karen, Nairobi, Kenya
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16
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Mather AE, Vaughan TG, French NP. Molecular Approaches to Understanding Transmission and Source Attribution in Nontyphoidal Salmonella and Their Application in Africa. Clin Infect Dis 2016; 61 Suppl 4:S259-65. [PMID: 26449940 DOI: 10.1093/cid/civ727] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Nontyphoidal Salmonella (NTS) is a frequent cause of diarrhea around the world, yet in many African countries it is more commonly associated with invasive bacterial disease. Various source attribution models have been developed that utilize microbial subtyping data to assign cases of human NTS infection to different animal populations and foods of animal origin. Advances in molecular microbial subtyping approaches, in particular whole-genome sequencing, provide higher resolution data with which to investigate these sources. In this review, we provide updates on the source attribution models developed for Salmonella, and examine the application of whole-genome sequencing data combined with evolutionary modeling to investigate the putative sources and transmission pathways of NTS, with a focus on the epidemiology of NTS in Africa. This is essential information to decide where, what, and how control strategies might be applied most effectively.
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Affiliation(s)
- Alison E Mather
- Department of Veterinary Medicine, University of Cambridge, United Kingdom
| | - Timothy G Vaughan
- Department of Computer Science, University of Auckland Allan Wilson Centre for Molecular Ecology and Evolution
| | - Nigel P French
- mEpiLab, Infectious Disease Research Centre, Massey University, Palmerston North, New Zealand
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17
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Afema JA, Byarugaba DK, Shah DH, Atukwase E, Nambi M, Sischo WM. Potential Sources and Transmission of Salmonella and Antimicrobial Resistance in Kampala, Uganda. PLoS One 2016; 11:e0152130. [PMID: 26999788 PMCID: PMC4801205 DOI: 10.1371/journal.pone.0152130] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2015] [Accepted: 03/09/2016] [Indexed: 01/12/2023] Open
Abstract
In sub‒Saharan Africa, non‒typhoidal Salmonellae (NTS) cause invasive disease particularly in children and HIV infected adults, but the disease epidemiology is poorly understood. Between 2012 and 2013, we investigated NTS sources and transmission in Kampala. We detected Salmonella in 60% of the influent and 60% of the effluent samples from a wastewater treatment plant and 53.3% of the influent and 10% of the effluent samples from waste stabilization ponds that serve the human population; 40.9% of flush‒water samples from ruminant slaughterhouses, 6.6% of the poultry fecal samples from live bird markets and 4% of the fecal samples from swine at slaughter; and in 54.2% of the water samples from a channel that drains storm–water and effluents from the city. We obtained 775 Salmonella isolates, identified 32 serovars, and determined resistance to 15 antimicrobials. We genotyped common serovars using multiple‒locus variable number tandem repeats analysis or pulsed‒field gel electrophoresis. In addition, we analyzed 49 archived NTS isolates from asymptomatic livestock and human clinical cases. Salmonella from ruminant and swine sources were mostly pan‒susceptible (95%) while poultry isolates were generally more resistant. Salmonella Kentucky isolated from poultry exhibited extensive drug resistance characterized by resistance to 10 antimicrobials. Interestingly, similar genotypes of S. Kentucky but with less antimicrobial resistance (AMR) were found in poultry, human and environmental sources. The observed AMR patterns could be attributed to host or management factors associated with production. Alternatively, S. Kentucky may be prone to acquiring AMR. The factors driving AMR remain poorly understood and should be elucidated. Overall, shared genotypes and AMR phenotypes were found in NTS from human, livestock and environmental sources, suggesting zoonotic and environmental transmissions most likely occur. Information from this study could be used to control NTS transmission.
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Affiliation(s)
- Josephine A. Afema
- Department of Veterinary Clinical Sciences, College of Veterinary Medicine, Washington State University, Pullman, WA, United States of America
- * E-mail:
| | - Denis K. Byarugaba
- Department of Biomolecular Resources and Biolaboratory Sciences, College of Veterinary Medicine and Animal Resources and Biosecurity, Makerere University, Kampala, Uganda
| | - Devendra H. Shah
- Department of Veterinary Microbiology and Pathology, College of Veterinary Medicine, Washington State University, Pullman, WA, United States of America
| | - Esther Atukwase
- Department of Biomolecular Resources and Biolaboratory Sciences, College of Veterinary Medicine and Animal Resources and Biosecurity, Makerere University, Kampala, Uganda
| | - Maria Nambi
- Department of Biomolecular Resources and Biolaboratory Sciences, College of Veterinary Medicine and Animal Resources and Biosecurity, Makerere University, Kampala, Uganda
| | - William M. Sischo
- Department of Veterinary Clinical Sciences, College of Veterinary Medicine, Washington State University, Pullman, WA, United States of America
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18
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Loss of Multicellular Behavior in Epidemic African Nontyphoidal Salmonella enterica Serovar Typhimurium ST313 Strain D23580. mBio 2016; 7:e02265. [PMID: 26933058 PMCID: PMC4810497 DOI: 10.1128/mbio.02265-15] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED Nontyphoidal Salmonella enterica serovar Typhimurium is a frequent cause of bloodstream infections in children and HIV-infected adults in sub-Saharan Africa. Most isolates from African patients with bacteremia belong to a single sequence type, ST313, which is genetically distinct from gastroenteritis-associated ST19 strains, such as 14028s and SL1344. Some studies suggest that the rapid spread of ST313 across sub-Saharan Africa has been facilitated by anthroponotic (person-to-person) transmission, eliminating the need for Salmonella survival outside the host. While these studies have not ruled out zoonotic or other means of transmission, the anthroponotic hypothesis is supported by evidence of extensive genomic decay, a hallmark of host adaptation, in the sequenced ST313 strain D23580. We have identified and demonstrated 2 loss-of-function mutations in D23580, not present in the ST19 strain 14028s, that impair multicellular stress resistance associated with survival outside the host. These mutations result in inactivation of the KatE stationary-phase catalase that protects high-density bacterial communities from oxidative stress and the BcsG cellulose biosynthetic enzyme required for the RDAR (red, dry, and rough) colonial phenotype. However, we found that like 14028s, D23580 is able to elicit an acute inflammatory response and cause enteritis in mice and rhesus macaque monkeys. Collectively, these observations suggest that African S. Typhimurium ST313 strain D23580 is becoming adapted to an anthroponotic mode of transmission while retaining the ability to infect and cause enteritis in multiple host species. IMPORTANCE The last 3 decades have witnessed an epidemic of invasive nontyphoidal Salmonella infections in sub-Saharan Africa. Genomic analysis and clinical observations suggest that the Salmonella strains responsible for these infections are evolving to become more typhoid-like with regard to patterns of transmission and virulence. This study shows that a prototypical African nontyphoidal Salmonella strain has lost traits required for environmental stress resistance, consistent with an adaptation to a human-to-human mode of transmission. However, in contrast to predictions, the strain remains capable of causing acute inflammation in the mammalian intestine. This suggests that the systemic clinical presentation of invasive nontyphoidal Salmonella infections in Africa reflects the immune status of infected hosts rather than intrinsic differences in the virulence of African Salmonella strains. Our study provides important new insights into the evolution of host adaptation in bacterial pathogens.
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19
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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: 640] [Impact Index Per Article: 71.1] [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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20
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Yang J, Barrila J, Roland KL, Kilbourne J, Ott CM, Forsyth RJ, Nickerson CA. Characterization of the Invasive, Multidrug Resistant Non-typhoidal Salmonella Strain D23580 in a Murine Model of Infection. PLoS Negl Trop Dis 2015; 9:e0003839. [PMID: 26091096 PMCID: PMC4474555 DOI: 10.1371/journal.pntd.0003839] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2015] [Accepted: 05/18/2015] [Indexed: 01/09/2023] Open
Abstract
A distinct pathovar of Salmonella enterica serovar Typhimurium, ST313, has emerged in sub-Saharan Africa as a major cause of fatal bacteremia in young children and HIV-infected adults. D23580, a multidrug resistant clinical isolate of ST313, was previously shown to have undergone genome reduction in a manner that resembles that of the more human-restricted pathogen, Salmonella enterica serovar Typhi. It has since been shown through tissue distribution studies that D23580 is able to establish an invasive infection in chickens. However, it remains unclear whether ST313 can cause lethal disease in a non-human host following a natural course of infection. Herein we report that D23580 causes lethal and invasive disease in a murine model of infection following peroral challenge. The LD50 of D23580 in female BALB/c mice was 4.7 x 105 CFU. Tissue distribution studies performed 3 and 5 days post-infection confirmed that D23580 was able to more rapidly colonize the spleen, mesenteric lymph nodes and gall bladder in mice when compared to the well-characterized S. Typhimurium strain SL1344. D23580 exhibited enhanced resistance to acid stress relative to SL1344, which may lend towards increased capability to survive passage through the gastrointestinal tract as well as during its intracellular lifecycle. Interestingly, D23580 also displayed higher swimming motility relative to SL1344, S. Typhi strain Ty2, and the ST313 strain A130. Biochemical tests revealed that D23580 shares many similar metabolic features with SL1344, with several notable differences in the Voges-Proskauer and catalase tests, as well alterations in melibiose, and inositol utilization. These results represent the first full duration infection study using an ST313 strain following the entire natural course of disease progression, and serve as a benchmark for ongoing and future studies into the pathogenesis of D23580. A deadly form of non-typhoidal Salmonella has emerged as a major cause of invasive disease in sub-Saharan Africa. Initial genomic profiling of this novel Salmonella sequence type, ST313, indicated that although it is technically classified as S. Typhimurium (a serovar characterized by a broad host range), it may be evolving towards becoming a more human-specific, ‘typhoid-like’ pathogen. However, it was recently demonstrated that ST313 strains were indeed able to establish an invasive and damaging infection in chickens. Despite these important findings, it remains unclear whether ST313 is able to cause lethal disease in a non-human host, since no study has yet followed the entire natural course of disease progression. As such, there are no data available concerning the median lethal dose (LD50) of any ST313 strain. This is an important metric, as the LD50 value will serve as a benchmark for mechanistic studies focused on understanding the relationship between virulence and the phenotypic and molecular genetic attributes associated with ST313 infections. Here we report that D23580 causes lethal disease in BALB/c mice and determined the LD50 following peroral challenge. Phenotypic characterization revealed distinct differences in tissue distribution, acid stress resistance, and biochemical utilization between D23580 and the ‘classic’ Typhimurium strain SL1344.
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Affiliation(s)
- Jiseon Yang
- Center for Infectious Diseases and Vaccinology, The Biodesign Institute, Arizona State University, Tempe, Arizona, United States of America
| | - Jennifer Barrila
- Center for Infectious Diseases and Vaccinology, The Biodesign Institute, Arizona State University, Tempe, Arizona, United States of America
| | - Kenneth L. Roland
- Center for Infectious Diseases and Vaccinology, The Biodesign Institute, Arizona State University, Tempe, Arizona, United States of America
| | - Jacquelyn Kilbourne
- Center for Infectious Diseases and Vaccinology, The Biodesign Institute, Arizona State University, Tempe, Arizona, United States of America
| | - C. Mark Ott
- Biomedical Research and Environmental Sciences Division, NASA Johnson Space Center, Houston, Texas, United States of America
| | - Rebecca J. Forsyth
- Center for Infectious Diseases and Vaccinology, The Biodesign Institute, Arizona State University, Tempe, Arizona, United States of America
| | - Cheryl A. Nickerson
- Center for Infectious Diseases and Vaccinology, The Biodesign Institute, Arizona State University, Tempe, Arizona, United States of America
- School of Life Sciences, Arizona State University, Tempe, Arizona, United States of America
- * E-mail:
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21
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A review of 40 years of enteric antimicrobial resistance research in Eastern Africa: what can be done better? Antimicrob Resist Infect Control 2015; 4:1. [PMID: 25717374 PMCID: PMC4339253 DOI: 10.1186/s13756-014-0041-4] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2014] [Accepted: 12/16/2014] [Indexed: 01/08/2023] Open
Abstract
The emergence and persistence of antimicrobial resistance is driven by varied factors including the indiscriminate use of antibiotics and variable drug efficacy and presents a major threat to the control of infectious diseases. Despite the high burden of disease in sub-Saharan Africa and the potential health and economic consequences, the level of research on antimicrobial resistance in the region remains unknown. Little data exists to quantify the contribution of different factors to the current levels of antimicrobial resistance. To identify the factors that contribute most to the emergence, amplification, persistence and dissemination of antimicrobial resistance in humans and animals, we used the PRISMA 2009 guidelines to conduct a systematic review of studies on antibiotic-resistant enteric bacteria in Eastern Africa. We searched PubMed and Google Scholar databases and identified 2,155 probable articles, of which 89 studies on humans and 28 on animals remained after full-text review. These were articles from Kenya, Tanzania, Uganda, Ethiopia, Rwanda and Burundi, published between 1974 and 2013, that reported resistance in Salmonella, Shigella, Escherichia coli and Vibrio sp. The majority (98%) of human studies were based on hospital- (rather than community-wide) sampling and although they report high levels of antimicrobial resistance in the region, study design and methodological differences preclude conclusions about the magnitude and trends of antimicrobial resistance. To remedy this, we discuss and propose minimum reporting guidelines for the level of detail that should be explicitly provided for antimicrobial resistance study designs, testing of samples and reporting of results that would permit comparative inferences and enable meta-analyses. Further, we advocate for increased focus on community- rather than hospital-based sampling to provide a better indication of population-wide trends in antimicrobial resistance. This approach, together with the establishment of a robust regional surveillance network, should over time build a pool of evidence-based data useful for policy decisions and interventions aimed at controlling antimicrobial resistance.
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MacLennan CA, Martin LB, Micoli F. Vaccines against invasive Salmonella disease: current status and future directions. Hum Vaccin Immunother 2014; 10:1478-93. [PMID: 24804797 PMCID: PMC4185946 DOI: 10.4161/hv.29054] [Citation(s) in RCA: 150] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
Though primarily enteric pathogens, Salmonellae are responsible for a considerable yet under-appreciated global burden of invasive disease. In South and South-East Asia, this manifests as enteric fever caused by serovars Typhi and Paratyphi A. In sub-Saharan Africa, a similar disease burden results from invasive nontyphoidal Salmonellae, principally serovars Typhimurium and Enteritidis. The existing Ty21a live-attenuated and Vi capsular polysaccharide vaccines target S. Typhi and are not effective in young children where the burden of invasive Salmonella disease is highest. After years of lack of investment in new Salmonella vaccines, recent times have seen increased interest in the area led by emerging-market manufacturers, global health vaccine institutes and academic partners. New glycoconjugate vaccines against S. Typhi are becoming available with similar vaccines against other invasive serovars in development. With other new vaccines under investigation, including live-attenuated, protein-based and GMMA vaccines, now is an exciting time for the Salmonella vaccine field.
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Affiliation(s)
- Calman A MacLennan
- Novartis Vaccines Institute for Global Health; Siena, Italy; Medical Research Council Centre for Immune Regulation and Clinical Immunology Service; Institute of Biomedical Research, School of Immunity and Infection; College of Medicine and Dental Sciences; University of Birmingham; Birmingham, UK
| | - Laura B Martin
- Novartis Vaccines Institute for Global Health; Siena, Italy
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Epidemiological analysis of Salmonella isolates recovered from food animals and humans in eastern China. Food Res Int 2013. [DOI: 10.1016/j.foodres.2013.07.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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Parsons BN, Humphrey S, Salisbury AM, Mikoleit J, Hinton JCD, Gordon MA, Wigley P. Invasive non-typhoidal Salmonella typhimurium ST313 are not host-restricted and have an invasive phenotype in experimentally infected chickens. PLoS Negl Trop Dis 2013; 7:e2487. [PMID: 24130915 PMCID: PMC3794976 DOI: 10.1371/journal.pntd.0002487] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2013] [Accepted: 09/03/2013] [Indexed: 01/12/2023] Open
Abstract
Salmonella enterica serovar Typhimurium Sequence Type (ST) 313 is a major cause of invasive non-Typhoidal salmonellosis in sub-Saharan Africa. No animal reservoir has been identified, and it has been suggested that ST313 is adapted to humans and transmission may occur via person-to-person spread. Here, we show that ST313 cause severe invasive infection in chickens as well as humans. Oral infection of chickens with ST313 isolates D23580 and Q456 resulted in rapid infection of spleen and liver with all birds infected at these sites by 3 days post-infection. In contrast, the well-defined ST19 S. Typhimurium isolates F98 and 4/74 were slower to cause invasive disease. Both ST19 and ST313 caused hepatosplenomegaly, and this was most pronounced in the ST313-infected animals. At 3 and 7 days post-infection, colonization of the gastrointestinal tract was lower in birds infected with the ST313 isolates compared with ST19. Histological examination and expression of CXCL chemokines in the ileum showed that both D23580 (ST313) and 4/74 (ST19) strains caused increased CXCL expression at 3 days post-infection, and this was significantly higher in the ileum of D23580 vs 4/74 infected birds. At 7 days post-infection, reduced chemokine expression occurred in the ileum of the D23580 but not 4/74-infected birds. Histological analysis showed that D23580 infection resulted in rapid inflammation and pathology including villous flattening and fusion at 3 days post-infection, and subsequent resolution by 7 days. In contrast, 4/74 induced less inflammation and pathology at 3 days post-infection. The data presented demonstrate that ST313 is capable of causing invasive disease in a non-human host. The rapid invasive nature of infection in the chicken, coupled with lower gastrointestinal colonization, supports the hypothesis that ST313 is a distinct pathovariant of S. Typhimurium that has evolved to become a systemic pathogen that can cause disease in several hosts. Salmonella enterica serovar Typhimurium usually causes foodborne diarrheal infections in humans. Recently variants of S. Typhimurium have emerged in Africa associated with invasive and often fatal disease, especially in adults infected by HIV and children with malaria or malnutrition. Analysis of these Sequence Type (ST) 313 isolates has identified significant genome degradation, compared with the ST19 genotype that typically causes diarrhea in humans. This is characterised by pseudogenes and deletions observed in the human-adapted S.Typhi. This has led to the hypothesis that the ST313 has become specifically adapted to humans. Here, we show ST313 also cause invasive disease in chickens, a common source of human Salmonella infection. As in humans, ST313 strains are more invasive than ST19 S. Typhimurium, and also cause less intestinal colonization. However, unlike Salmonella serotypes associated with invasive disease in the chicken, ST313 causes inflammation and damage to the intestine. These findings suggest that ST313 is not host-restricted to humans, and may have evolved to cause a more invasive disease in a range of hosts. We highlight the fact that animals, including chickens, could still be a source of ST313 and that further epidemiological research is needed into potential animal reservoirs of ST313 in Africa.
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Affiliation(s)
- Bryony N. Parsons
- ZIPPP Group, Institute of Infection and Global Health, University of Liverpool, Neston, Cheshire, United Kingdom
- Institute of Translational Medicine University of Liverpool, Liverpool, United Kingdom
| | - Suzanne Humphrey
- ZIPPP Group, Institute of Infection and Global Health, University of Liverpool, Neston, Cheshire, United Kingdom
| | - Anne Marie Salisbury
- ZIPPP Group, Institute of Infection and Global Health, University of Liverpool, Neston, Cheshire, United Kingdom
| | - Julia Mikoleit
- ZIPPP Group, Institute of Infection and Global Health, University of Liverpool, Neston, Cheshire, United Kingdom
| | - Jay C. D. Hinton
- Institute of Integrative Biology, University of Liverpool, Liverpool, United Kingdom
| | - Melita A. Gordon
- Institute of Translational Medicine University of Liverpool, Liverpool, United Kingdom
| | - Paul Wigley
- ZIPPP Group, Institute of Infection and Global Health, University of Liverpool, Neston, Cheshire, United Kingdom
- * E-mail:
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MacLennan CA, Tennant SM. Comparing the roles of antibodies to nontyphoidal Salmonella enterica in high- and low-income countries and implications for vaccine development. CLINICAL AND VACCINE IMMUNOLOGY : CVI 2013; 20:1487-90. [PMID: 23904457 PMCID: PMC3807204 DOI: 10.1128/cvi.00465-13] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Affiliation(s)
- Calman A. MacLennan
- Novartis Vaccines Institute for Global Health, Siena, Italy
- MRC Centre for Immune Regulation, School of Immunity and Infection, College of Medicine and Dental Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Sharon M. Tennant
- Center for Vaccine Development
- Department of Medicine, University of Maryland School of Medicine, Baltimore, Maryland, USA
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Msefula CL, Kingsley RA, Gordon MA, Molyneux E, Molyneux ME, MacLennan CA, Dougan G, Heyderman RS. Genotypic homogeneity of multidrug resistant S. Typhimurium infecting distinct adult and childhood susceptibility groups in Blantyre, Malawi. PLoS One 2012; 7:e42085. [PMID: 22848711 PMCID: PMC3407126 DOI: 10.1371/journal.pone.0042085] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2012] [Accepted: 07/02/2012] [Indexed: 01/10/2023] Open
Abstract
Nontyphoidal Salmonella (NTS) serovars are a common cause of bacteraemia in young children and HIV-infected adults in Malawi and elsewhere in sub-Saharan Africa. These patient populations provide diverse host-immune environments that have the potential to drive bacterial adaptation and evolution. We therefore investigated the diversity of 27 multidrug resistant (MDR) Salmonella Typhimurium strains isolated over 6 years (2002-2008) from HIV-infected adults and children and HIV-uninfected children. Sequence reads from whole-genome sequencing of these isolates using the Illumina GA platform were mapped to the genome of the laboratory strain S. Typhimurium SL1344 excluding homoplastic regions that contained prophage and insertion elements. A phylogenetic tree generated from single nucleotide polymorphisms showed that all 27 strains clustered with the prototypical MDR strain D23580. There was no clustering of strains based on host HIV status or age, suggesting that these susceptible populations acquire S. Typhimurium from common sources or that isolates are transmitted freely between these populations. However, 7/14 of the most recent isolates (2006/2008) formed a distinct clade that branched off 22 SNPs away from the cluster containing earlier isolates. These data suggest that the MDR bacterial population is not static, but is undergoing microevolution which might result in further epidemiology change.
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Affiliation(s)
- Chisomo L Msefula
- Department of Microbiology, College of Medicine, University of Malawi, Blantyre, Malawi.
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Development of protective immunity to Salmonella, a mucosal pathogen with a systemic agenda. Mucosal Immunol 2011; 4:371-82. [PMID: 21307847 PMCID: PMC4084725 DOI: 10.1038/mi.2011.2] [Citation(s) in RCA: 103] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Salmonella infections can cause a range of intestinal and systemic diseases in human and animal hosts. Although some Salmonella serovars initiate a localized intestinal inflammatory response, others use the intestine as a portal of entry to initiate a systemic infection. Considerable progress has been made in understanding bacterial invasion and dissemination strategies, as well as the nature of the Salmonella-specific immune response to oral infection. Innate and adaptive immunity are rapidly initiated after oral infection, but these effector responses can also be hindered by bacterial evasion strategies. Furthermore, although Salmonella resides within intramacrophage phagosomes, recent studies have highlighted a surprising collaboration of CD4 Th1, Th17, and B-cell responses in mediating resistance to Salmonella infection.
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Dione MM, Ikumapayi UN, Saha D, Mohammed NI, Geerts S, Ieven M, Adegbola RA, Antonio M. Clonal differences between Non-Typhoidal Salmonella (NTS) recovered from children and animals living in close contact in the Gambia. PLoS Negl Trop Dis 2011; 5:e1148. [PMID: 21655353 PMCID: PMC3104961 DOI: 10.1371/journal.pntd.0001148] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2010] [Accepted: 03/15/2011] [Indexed: 11/23/2022] Open
Abstract
Background Non-Typhoidal Salmonella (NTS) is an important cause of invasive bacterial disease and associated with mortality in Africa. However, little is known about the environmental reservoirs and predominant modes of transmission. Our study aimed to study the role of domestic animals in the transmission of NTS to humans in rural area of The Gambia. Methodology Human NTS isolates were obtained through an active population-based case-control surveillance study designated to determine the aetiology and epidemiology of enteric infections covering 27,567 Gambian children less than five years of age in the surveillance area. Fourteen children infected with NTS were traced back to their family compounds and anal swabs collected from 210 domestic animals present in their households. Identified NTSs were serotyped and genotyped by multi-locus sequencing typing. Principal Findings NTS was identified from 21/210 animal sources in the households of the 14 infected children. Chickens carried NTS more frequently than sheep and goats; 66.6%, 28.6% and 4.8% respectively. The most common NTS serovars were S. Colindale in humans (21.42%) and S. Poona in animals (14.28%). MLST on the 35 NTS revealed four new alleles and 24 sequence types (ST) of which 18 (75%) STs were novel. There was no overlap in serovars or genotypes of NTS recovered from humans or animal sources in the same household. Conclusion Our results do not support the hypothesis that humans and animals in close contact in the same household carry genotypically similar Salmonella serovars. These findings form an important baseline for future studies of transmission of NTS in humans and animals in Africa. Salmonellosis is a neglected tropical disease causing serious dysentery and septicaemia particularly in young infants, elderly and immunocompromised individuals such as HIV patients and associated with substantial mortality in developing countries. Salmonellosis also constitutes a major public health problem as it is considered the most widespread bacterial zoonosis of food origin throughout the world. Many epidemiological data exist from developed countries concerning transmission of Non-Typhoidal Salmonella (NTS) but few are available from developing countries. In addition few studies in sub-Saharan Africa have considered the interface between humans and their environment in relation to animals present in the household and food hygiene. This study describes the prevalence of NTS among fourteen Gambian children and 210 domestic animals living in close proximity (household) to the children in a rural setting in The Gambia. We found that the domestic animals living in the same household as patients carried different NTS serovar and genotypes; indicating that zoonotic transmission does not occur in our setting. This study provides baseline data for future studies of transmission of NTS in rural Africa.
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Affiliation(s)
- Michel M. Dione
- International Trypanotolerance Centre, Banjul, The Gambia
- Institute of Tropical Medicine, Antwerp, Belgium
- University of Antwerp, Antwerp, Belgium
| | | | - Debasish Saha
- Medical Research Council (UK) Laboratories, Banjul, The Gambia
| | | | | | | | | | - Martin Antonio
- Medical Research Council (UK) Laboratories, Banjul, The Gambia
- * E-mail:
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Simon R, Tennant SM, Galen JE, Levine MM. Mouse models to assess the efficacy of non-typhoidal Salmonella vaccines: revisiting the role of host innate susceptibility and routes of challenge. Vaccine 2011; 29:5094-106. [PMID: 21616112 DOI: 10.1016/j.vaccine.2011.05.022] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2011] [Revised: 04/22/2011] [Accepted: 05/09/2011] [Indexed: 01/24/2023]
Abstract
Non-typhoidal Salmonella enterica (NTS) serovars Typhimurium and Enteritidis are important causes of bacterial gastroenteritis in the USA and worldwide. In sub-Saharan Africa these two serovars are emerging as agents associated with lethal invasive disease (e.g., bacteremia, meningitis). The development of NTS vaccines, based on mucosally administered live attenuated strains and parenteral non-living antigens, could diminish the NTS disease burden globally. Mouse models of S. Typhimurium and S. Enteritidis invasive disease can accelerate the development of NTS vaccines. Live attenuated NTS vaccines elicit both cellular and humoral immunity in mice and their efficacy is well established. In contrast, non-living vaccines that primarily elicit humoral immunity have demonstrated variable efficacy. An analysis of the reported studies with non-living vaccines against S. Typhimurium and S. Enteritidis reveals that efficacy is influenced by two important independent variables: (1) the innate susceptibility to NTS infection that differs dramatically between commonly used mouse strains and (2) the virulence of the NTS strain used for challenge. Protection by non-living vaccines has generally been seen only in host-pathogen interactions where a sub-lethal infection results, such as challenging resistant mice with either highly virulent or weakly virulent strains or susceptible mice with weakly virulent strains. The immunologic basis of this discrepancy and the implications for human NTS vaccine development are reviewed herein.
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Affiliation(s)
- Raphael Simon
- Center for Vaccine Development, University of Maryland School of Medicine, Baltimore, MD, 21201, USA.
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Cox N, Cason J, Richardson L. Minimization ofSalmonellaContamination on Raw Poultry. Annu Rev Food Sci Technol 2011; 2:75-95. [DOI: 10.1146/annurev-food-022510-133715] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- N.A. Cox
- USDA/Agricultural Research Service, Russell Research Center, Athens, Georgia 30605;
| | - J.A. Cason
- USDA/Agricultural Research Service, Russell Research Center, Athens, Georgia 30605;
| | - L.J. Richardson
- Current address: The Coca Cola Company, Atlanta, Georgia 30313;
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Mead G, Lammerding AM, Cox N, Doyle MP, Humbert F, Kulikovskiy A, Panin A, do Nascimento VP, Wierup M. Scientific and technical factors affecting the setting of Salmonella criteria for raw poultry: a global perspective. J Food Prot 2010; 73:1566-90. [PMID: 20819373 DOI: 10.4315/0362-028x-73.8.1566] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Concerns about foodborne salmonellosis have led many countries to introduce microbiological criteria for certain food products. If such criteria are not well-grounded in science, they could be an unjustified obstacle to trade. Raw poultry products are an important part of the global food market. Import and export ambiguities and regulatory confusion resulting from different Salmonella requirements were the impetus for convening an international group of scientific experts from 16 countries to discuss the scientific and technical issues that affect the setting of a microbiological criterion for Salmonella contamination of raw chicken. A particular concern for the group was the use of criteria implying a zero tolerance for Salmonella and suggesting complete absence of the pathogen. The notion can be interpreted differently by various stakeholders and was considered inappropriate because there is neither an effective means of eliminating Salmonella from raw poultry nor any practical method for verifying its absence. Therefore, it may be more useful at present to set food safety metrics that involve reductions in hazard levels. Such terms as "zero tolerance" or "absence of a microbe" in relation to raw poultry should be avoided unless defined and explained by international agreement. Risk assessment provides a more meaningful approach than a zero tolerance philosophy, and new metrics, such as performance objectives that are linked to human health outcomes, should be utilized throughout the food chain to help define risk and identify ways to reduce adverse effects on public health.
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Chimalizeni Y, Kawaza K, Molyneux E. The epidemiology and management of non typhoidal salmonella infections. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2010; 659:33-46. [PMID: 20204753 DOI: 10.1007/978-1-4419-0981-7_3] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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MacLennan CA, Gondwe EN, Msefula CL, Kingsley RA, Thomson NR, White SA, Goodall M, Pickard DJ, Graham SM, Dougan G, Hart CA, Molyneux ME, Drayson MT. The neglected role of antibody in protection against bacteremia caused by nontyphoidal strains of Salmonella in African children. J Clin Invest 2008; 118:1553-62. [PMID: 18357343 DOI: 10.1172/jci33998] [Citation(s) in RCA: 182] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2007] [Accepted: 02/13/2008] [Indexed: 11/17/2022] Open
Abstract
Nontyphoidal strains of Salmonella (NTS) are a common cause of bacteremia among African children. Cell-mediated immune responses control intracellular infection, but they do not protect against extracellular growth of NTS in the blood. We investigated whether antibody protects against NTS bacteremia in Malawian children, because we found this condition mainly occurs before 2 years of age, with relative sparing of infants younger than 4 months old. Sera from all healthy Malawian children tested aged more than 16 months contained anti-Salmonella antibody and successfully killed NTS. Killing was mediated by complement membrane attack complex and not augmented in the presence of blood leukocytes. Sera from most healthy children less than 16 months old lacked NTS-specific antibody, and sera lacking antibody did not kill NTS despite normal complement function. Addition of Salmonella-specific antibody, but not mannose-binding lectin, enabled NTS killing. All NTS strains tested had long-chain lipopolysaccharide and the rck gene, features that resist direct complement-mediated killing. Disruption of lipopolysaccharide biosynthesis enabled killing of NTS by serum lacking Salmonella-specific antibody. We conclude that Salmonella-specific antibody that overcomes the complement resistance of NTS develops by 2 years of life in Malawian children. This finding and the age-incidence of NTS bacteremia suggest that antibody protects against NTS bacteremia and support the development of vaccines against NTS that induce protective antibody.
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Affiliation(s)
- Calman A MacLennan
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, College of Medicine, University of Malawi, Blantyre, Malawi.
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Douris A, Fedorka-Cray PJ, Jackson CR. Characterization of Salmonella enterica Serovar Agona Slaughter Isolates from the Animal Arm of the National Antimicrobial Resistance Monitoring System—Enteric Bacteria (NARMS): 1997 through 2003. Microb Drug Resist 2008; 14:55-63. [DOI: 10.1089/mdr.2008.0787] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Aphrodite Douris
- Bacterial Epidemiology and Antimicrobial Resistance Research Unit, U.S. Department of Agriculture, Agricultural Research Service, Athens, Georgia
| | - Paula J. Fedorka-Cray
- Bacterial Epidemiology and Antimicrobial Resistance Research Unit, U.S. Department of Agriculture, Agricultural Research Service, Athens, Georgia
| | - Charlene R. Jackson
- Bacterial Epidemiology and Antimicrobial Resistance Research Unit, U.S. Department of Agriculture, Agricultural Research Service, Athens, Georgia
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Kikuvi GM, Schwarz S, Ombui JN, Mitema ES, Kehrenberg C. Streptomycin and Chloramphenicol Resistance Genes inEscherichia coliIsolates from Cattle, Pigs, and Chicken in Kenya. Microb Drug Resist 2007; 13:62-8. [PMID: 17536935 DOI: 10.1089/mdr.2006.9998] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The aims of this study were to determine the genetic basis of streptomycin and chloramphenicol resistance in 30 Escherichia coli isolates from food animals in Kenya and the role of plasmids in the spread of the resistance. Seven of the 29 streptomycin-resistant isolates harbored both the strA and strB genes. Twenty-one of isolates had the strA, strB, and aadA1 genes. The strA gene was disrupted by a functional trimethoprim gene, dfrA14 in 10 of the 21 isolates harboring the three streptomycin resistance genes. Physical linkage of intact strA and sul2 genes was found in two different plasmids from four isolates. Linkage of cassette-borne aadA1 and dfrA1 genes in class 1 integrons was found in two of the isolates. Chloramphenicol resistance was due to the gene catA1 in all the chloramphenicol resistant isolates. The strB, strA, and catA1 genes were transferable by conjugation and this points to the significance of conjugative resistance plasmids in the spread and persistence of streptomycin and chloramphenicol resistance in food animals in Kenya.
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Affiliation(s)
- G M Kikuvi
- Institute of Tropical Medicine and Infectious Diseases, Jomo Kenyatta University of Agriculture and Technology, Nairobi, Kenya.
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Kariuki S, Revathi G, Kariuki N, Kiiru J, Mwituria J, Muyodi J, Githinji JW, Kagendo D, Munyalo A, Hart CA. Invasive multidrug-resistant non-typhoidal Salmonella infections in Africa: zoonotic or anthroponotic transmission? J Med Microbiol 2006; 55:585-591. [PMID: 16585646 DOI: 10.1099/jmm.0.46375-0] [Citation(s) in RCA: 138] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
In Africa, multidrug-resistant non-typhoidal salmonellae (NTS) are one of the leading causes of morbidity and high mortality in children under 5 years of age, second in importance only to pneumococcal disease. The authors studied NTS isolates from paediatric admissions at two hospitals in Nairobi, Kenya, and followed the index cases to their homes, where rectal swabs and stools from parents and siblings, and from animals in close contact, were obtained. The majority of NTS obtained from cases were Salmonella enterica serotype Typhimurium (106 out of 193; 54.9%) and Salmonella enterica serotype Enteritidis (64; 33.2%), a significant proportion (34.2%) of which were multiply resistant to three or more antibiotics, including ampicillin, tetracycline, cotrimoxazole and chloramphenicol. Only 23.4% of NTS were fully susceptible to all 10 antibiotics tested. Of the 32 NTS obtained from contacts (nine adults and 23 children) at the homes of index cases, 21 (65.6%) isolates were similar by antibiotic-susceptibility profiles and plasmid content, and their XbaI- and SpeI-digested chromosomal DNA patterns were indistinguishable from those of the corresponding index cases. Only three out of 180 (1.7%) samples from environmental sources, including animals, soil, sewers and food, contained NTS matching those from corresponding index cases. The carriage of NTS in an asymptomatic population was represented by 6.9% of human contacts from 27 out of 127 homes sampled. This population of carriers may represent an important reservoir of NTS that would play a significant role in the epidemiology of community-acquired NTS bacteraemia in children.
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Affiliation(s)
- Samuel Kariuki
- Department of Medical Microbiology and Genito-Urinary Medicine, University of Liverpool, Liverpool L69 3GA, UK
- Centre for Microbiology Research, Kenya Medical Research Institute, PO Box 43640, Nairobi, Kenya
| | - Gunturu Revathi
- Department of Medical Microbiology, Kenyatta National Hospital, PO Box 20723, Nairobi, Kenya
| | - Nyambura Kariuki
- Department of Medical Microbiology, Kenyatta National Hospital, PO Box 20723, Nairobi, Kenya
| | - John Kiiru
- Centre for Microbiology Research, Kenya Medical Research Institute, PO Box 43640, Nairobi, Kenya
| | - Joyce Mwituria
- Centre for Microbiology Research, Kenya Medical Research Institute, PO Box 43640, Nairobi, Kenya
| | - Jane Muyodi
- Centre for Microbiology Research, Kenya Medical Research Institute, PO Box 43640, Nairobi, Kenya
| | - Jane W Githinji
- Central Veterinary Investigations Laboratory, PO Private Bag, Kabete, Kenya
| | - Dorothy Kagendo
- Centre for Microbiology Research, Kenya Medical Research Institute, PO Box 43640, Nairobi, Kenya
| | - Agnes Munyalo
- Centre for Microbiology Research, Kenya Medical Research Institute, PO Box 43640, Nairobi, Kenya
| | - C Anthony Hart
- Department of Medical Microbiology and Genito-Urinary Medicine, University of Liverpool, Liverpool L69 3GA, UK
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Kariuki S, Revathi G, Kariuki N, Muyodi J, Mwituria J, Munyalo A, Kagendo D, Murungi L, Anthony Hart C. Increasing prevalence of multidrug-resistant non-typhoidal salmonellae, Kenya, 1994–2003. Int J Antimicrob Agents 2005; 25:38-43. [PMID: 15620824 DOI: 10.1016/j.ijantimicag.2004.08.015] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2004] [Accepted: 08/27/2004] [Indexed: 11/26/2022]
Abstract
Over the last decade there has been a steady increase in the proportion of multidrug resistance among non-typhoidal salmonellae (NTS) isolated from adult patients with bacteraemia in Kenya. The prevalence of NTS multiply resistant to all commonly available drugs including ampicillin, streptomycin, co-trimoxazole, chloramphenicol and tetracycline rose from 31% in 1994 to 42% at present, with concomitantly higher MICs of each drug. Resistance is encoded on large self-transferable 100-110 kb plasmids. Pulsed field gel electrophoresis of XbaI and SpeI digested chromosomal DNA revealed three main digest patterns for Salmonella enterica serotype Typhimurium and two main patterns for Salmonella enterica serotype Enteritidis. Although the genotypes of NTS remained fairly stable over the last decade, the large increase in MICs of all commonly used drugs and increased MICs of ciprofloxacin, poses a major challenge for treatment of invasive NTS infection.
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Affiliation(s)
- Samuel Kariuki
- Centre for Microbiology Research, Kenya Medical Research Institute, PO Box 43640, Nairobi, Kenya.
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Alvarez J, Porwollik S, Laconcha I, Gisakis V, Vivanco AB, Gonzalez I, Echenagusia S, Zabala N, Blackmer F, McClelland M, Rementeria A, Garaizar J. Detection of a Salmonella enterica serovar California strain spreading in spanish feed mills and genetic characterization with DNA microarrays. Appl Environ Microbiol 2004; 69:7531-4. [PMID: 14660409 PMCID: PMC309902 DOI: 10.1128/aem.69.12.7531-7534.2003] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We performed an epidemiological study on Salmonella isolated from raw plant-based feed in Spanish mills. Overall, 32 different Salmonella serovars were detected. Despite its rare occurrence in humans and animals, Salmonella enterica serovar California was found to be the predominant serovar in Spanish feed mills. Different typing techniques showed that isolates of this serovar were genetically closely related, and comparative genomic hybridization using microarray technology revealed 23 S. enterica serovar Typhimurium LT2 gene clusters that are absent from serovar California.
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Affiliation(s)
- Juan Alvarez
- Department of Immunology, Microbiology, and Parasitology, School of Pharmacy, University of the Basque Country, 01006 Vitoria-Gasteiz, Spain
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Wilson JS, Hazel SM, Williams NJ, Phiri A, French NP, Hart CA. Nontyphoidal salmonellae in United Kingdom badgers: prevalence and spatial distribution. Appl Environ Microbiol 2003; 69:4312-5. [PMID: 12839821 PMCID: PMC165146 DOI: 10.1128/aem.69.7.4312-4315.2003] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Eighteen (72%) of 25 badger social groups were found to excrete Salmonella enterica serovar Ried, S. enterica serovar Binza, S. enterica serovar Agama, or S. enterica serovar Lomita. Each serovar was susceptible to a panel of antimicrobials. Based on results of pulsed-field gel electrophoresis, the S. enterica serovar Agama and S. enterica serovar Binza isolates were very similar, but two clones each of S. enterica serovar Lomita and S. enterica serovar Ried were found. Badgers excreting S. enterica serovar Agama were spatially clustered.
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Affiliation(s)
- J Sian Wilson
- Department of Medical Microbiology and Genito-Urinary Medicine, University of Liverpool, Duncan Building, Daulby Street, Liverpool L69 3GA, United Kingdom
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