1
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Mylona E, Hefele L, Tran Vu Thieu N, Trinh Van T, Nguyen Ngoc Minh C, Tran Tuan A, Karkey A, Dongol S, Basnyat B, Voong Vinh P, Ho Ngoc Dan T, Russell P, Charles RC, Parry CM, Baker S. The Identification of Enteric Fever-Specific Antigens for Population-Based Serosurveillance. J Infect Dis 2024; 229:833-844. [PMID: 37403670 PMCID: PMC10938218 DOI: 10.1093/infdis/jiad242] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2023] [Revised: 06/21/2023] [Accepted: 07/04/2023] [Indexed: 07/06/2023] Open
Abstract
BACKGROUND Enteric fever, caused by Salmonella enterica serovars Typhi and Paratyphi A, is a major public health problem in low- and middle-income countries. Moderate sensitivity and scalability of current methods likely underestimate enteric fever burden. Determining the serological responses to organism-specific antigens may improve incidence measures. METHODS Plasma samples were collected from blood culture-confirmed enteric fever patients, blood culture-negative febrile patients over the course of 3 months, and afebrile community controls. A panel of 17 Salmonella Typhi and Paratyphi A antigens was purified and used to determine antigen-specific antibody responses by indirect ELISAs. RESULTS The antigen-specific longitudinal antibody responses were comparable between enteric fever patients, patients with blood culture-negative febrile controls, and afebrile community controls for most antigens. However, we found that IgG responses against STY1479 (YncE), STY1886 (CdtB), STY1498 (HlyE), and the serovar-specific O2 and O9 antigens were greatly elevated over a 3-month follow up period in S. Typhi/S. Paratyphi A patients compared to controls, suggesting seroconversion. CONCLUSIONS We identified a set of antigens as good candidates to demonstrate enteric fever exposure. These targets can be used in combination to develop more sensitive and scalable approaches to enteric fever surveillance and generate invaluable epidemiological data for informing vaccine policies. CLINICAL TRIAL REGISTRATION ISRCTN63006567.
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Affiliation(s)
- Elli Mylona
- Cambridge Institute of Therapeutic Immunology and Infectious Disease, University of Cambridge School of Clinical Medicine, Cambridge, United Kingdom
- Department of Medicine, University of Cambridge School of Clinical Medicine, Cambridge, United Kingdom
| | - Lisa Hefele
- Department of Infection and Immunity, Luxembourg Institute of Health, Esch-sur-Alzette, Grand Duchy of Luxembourg
| | - Nga Tran Vu Thieu
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
| | - Tan Trinh Van
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
| | - Chau Nguyen Ngoc Minh
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
| | - Anh Tran Tuan
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
| | - Abhilasha Karkey
- Oxford University Clinical Research Unit, Patan Academy of Health Sciences, Kathmandu, Nepal
| | - Sabina Dongol
- Oxford University Clinical Research Unit, Patan Academy of Health Sciences, Kathmandu, Nepal
| | - Buddha Basnyat
- Oxford University Clinical Research Unit, Patan Academy of Health Sciences, Kathmandu, Nepal
| | - Phat Voong Vinh
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
| | - Thanh Ho Ngoc Dan
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
| | - Paula Russell
- Cambridge Institute of Therapeutic Immunology and Infectious Disease, University of Cambridge School of Clinical Medicine, Cambridge, United Kingdom
- Department of Medicine, University of Cambridge School of Clinical Medicine, Cambridge, United Kingdom
| | | | - Christopher M Parry
- Centre for Tropical Medicine, Oxford University, Oxford, United Kingdom
- Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Stephen Baker
- Cambridge Institute of Therapeutic Immunology and Infectious Disease, University of Cambridge School of Clinical Medicine, Cambridge, United Kingdom
- Department of Medicine, University of Cambridge School of Clinical Medicine, Cambridge, United Kingdom
- IAVI Human Immunology Laboratory, Imperial College London, London, UK
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2
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Nguyen Thi Nguyen T, Parry CM, Campbell JI, Vinh PV, Kneen R, Baker S. Endemic erythromycin resistant Corynebacterium diphtheriae in Vietnam in the 1990s. Microb Genom 2022; 8:mgen000861. [PMID: 36259695 PMCID: PMC9676054 DOI: 10.1099/mgen.0.000861] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Accepted: 06/10/2022] [Indexed: 11/18/2022] Open
Abstract
Diphtheria is a potentially fatal respiratory disease caused by toxigenic forms of the Gram-positive bacterium Corynebacterium diphtheriae. Despite the availability of treatments (antitoxin and antimicrobials) and effective vaccines, the disease still occurs sporadically in low-income countries and in higher income where use of diphtheria vaccine is inconsistent. Diphtheria was highly endemic in Vietnam in the 1990s; here, we aimed to provide some historical context to the circulation of erythromycin resistant organisms in Vietnam during this period. After recovering 54 C. diphtheriae isolated from clinical cases of diphtheria in Ho Chi Minh City between 1992 and 1998 we conducted whole genome sequencing and analysis. Our data outlined substantial genetic diversity among the isolates, illustrated by seven distinct Sequence Types (STs), but punctuated by the sustained circulation of ST67 and ST209. With the exception of one isolate, all sequences contained the tox gene, which was classically located on a corynebacteriophage. All erythromycin resistant isolates, accounting for 13 % of organisms in this study, harboured a novel 18 kb erm(X)-carrying plasmid, which exhibited limited sequence homology to previously described resistance plasmids in C. diphtheriae. Our study provides historic context for the circulation of antimicrobial resistant C. diphtheriae in Vietnam; these data provide a framework for the current trajectory in global antimicrobial resistance trends.
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Affiliation(s)
- To Nguyen Thi Nguyen
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
- Department of Microbiology, Monash University, Melbourne, Victoria, Australia
| | - Christopher M. Parry
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
- Clinical Sciences, Liverpool School of Tropical Medicine, Pembroke Pl, Liverpool L3 5QA, UK
- Alder Hey Children’s Hospital, NHS Foundation Trust, Liverpool, UK
| | - James I. Campbell
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Phat Voong Vinh
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
| | - Rachel Kneen
- Alder Hey Children’s Hospital, NHS Foundation Trust, Liverpool, UK
- Institute of Infection and Global Health, University of Liverpool, Liverpool L69 3BX, UK
| | - Stephen Baker
- University of Cambridge School of Clinical Medicine, Cambridge Biomedical Campus, Cambridge, UK
- Department of Medicine, University of Cambridge School of Clinical Medicine, Cambridge Biomedical Campus, Cambridge, UK
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3
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Fernández Álvaro E, Voong Vinh P, de Cozar C, Willé DR, Urones B, Cortés A, Price A, Tran Do Hoang N, Ha Thanh T, McCloskey M, Shaheen S, Dayao D, Martinot A, de Mercado J, Castañeda P, García-Perez A, Singa B, Pavlinac P, Walson J, Martínez-Martínez MS, Arnold SLM, Tzipori S, Pages LB, Baker S. Correction: The repurposing of Tebipenem pivoxil as alternative therapy for severe gastrointestinal infections caused by extensively drug-resistant Shigella spp. eLife 2022; 11:83117. [PMID: 36063387 PMCID: PMC9444238 DOI: 10.7554/elife.83117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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4
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The HC, Bodhidatta L, Pham DT, Mason CJ, Thanh TH, Vinh PV, Turner P, Hem S, Dance DAB, Newton PN, Phetsouvanh R, Davong V, Thwaites GE, Thomson NR, Baker S, Rabaa MA. Evolutionary histories and antimicrobial resistance inShigella flexneri and Shigella sonnei in Southeast Asia. Access Microbiol 2022. [DOI: 10.1099/acmi.ac2021.po0330] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Conventional disease surveillance for shigellosis in developing country settingsrelies on serotyping and low-resolution molecular typing, which fails to contextualise the evolutionary history of the genus. Here, we interrogated a collection of 1,804 Shigella whole genome sequences from organisms isolated in four continental Southeast Asian countries (Thailand, Vietnam, Laos, and Cambodia) over three decades to characterise the evolution of both S. flexneri and S. sonnei. We show that S. sonnei and each major S. flexneri serotype are comprised of genetically diverse populations, the majority of which were likely introduced into Southeast Asia in the 1970s-1990s. Intranational and regional dissemination allowed widespread propagation of both species across the region. Our data indicate that the epidemiology of S. sonnei and the major S. flexneri serotypes were characterised by frequent clonal replacement events, coinciding with changing susceptibility patterns against contemporaneous antimicrobials. We conclude that adaptation to antimicrobial pressure was pivotal to the recent evolutionary trajectory of Shigella in Southeast Asia.
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Affiliation(s)
| | | | - Duy Thanh Pham
- Centre for Tropical Medicine and Global Health, University of Oxford, United Kingdom
- Oxford University Clinical Research Unit, Vietnam
| | - Carl J. Mason
- Armed Forces Research Institute of Medical Sciences, Thailand
| | | | | | - Paul Turner
- Centre for Tropical Medicine and Global Health, University of Oxford, United Kingdom
- Cambodia-Oxford Medical Research Unit, Cambodia
| | | | - David A. B. Dance
- London School of Hygiene and Tropical Medicine, United Kingdom
- Centre for Tropical Medicine and Global Health, University of Oxford, United Kingdom
- Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit, Lao, People’s Democratic Republic
| | - Paul N. Newton
- London School of Hygiene and Tropical Medicine, United Kingdom
- Centre for Tropical Medicine and Global Health, University of Oxford, United Kingdom
- Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit, Lao, People’s Democratic Republic
| | - Rattanaphone Phetsouvanh
- Centre for Tropical Medicine and Global Health, University of Oxford, United Kingdom
- Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit, Lao, People’s Democratic Republic
| | - Viengmon Davong
- Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit, Lao, People’s Democratic Republic
| | - Guy E. Thwaites
- Centre for Tropical Medicine and Global Health, University of Oxford, United Kingdom
- Oxford University Clinical Research Unit, Vietnam
| | - Nicholas R. Thomson
- London School of Hygiene and Tropical Medicine, United Kingdom
- The Wellcome Trust Sanger Institute, United Kingdom
| | - Stephen Baker
- The Department of Medicine, University of Cambridge, United Kingdom
| | - Maia A. Rabaa
- Centre for Tropical Medicine and Global Health, University of Oxford, United Kingdom
- Oxford University Clinical Research Unit, Vietnam
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5
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Fernández Alvaro E, Voong Vinh P, de Cozar C, Wille D, Urones B, Cortés A, Price A, Tran Do Hoang N, Ha Thanh T, McCloskey M, Shaheen S, Dayao D, de Mercado J, Castañeda P, García-Perez A, Singa B, Pavlinac P, Walson J, Martínez-Martínez MS, Arnold SLM, Saul T, Ballell L, Baker S. The repurposing of Tebipenem pivoxil as alternative therapy for severe gastrointestinal infections caused by extensively drug resistant Shigella spp. eLife 2022; 11:69798. [PMID: 35289746 PMCID: PMC8959600 DOI: 10.7554/elife.69798] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Accepted: 03/09/2022] [Indexed: 11/18/2022] Open
Abstract
Background: Diarrhoea remains one of the leading causes of childhood mortality globally. Recent epidemiological studies conducted in low-middle income countries (LMICs) identified Shigella spp. as the first and second most predominant agent of dysentery and moderate diarrhoea, respectively. Antimicrobial therapy is often necessary for Shigella infections; however, we are reaching a crisis point with efficacious antimicrobials. The rapid emergence of resistance against existing antimicrobials in Shigella spp. poses a serious global health problem. Methods: Aiming to identify alternative antimicrobial chemicals with activity against antimicrobial resistant Shigella, we initiated a collaborative academia-industry drug discovery project, applying high-throughput phenotypic screening across broad chemical diversity and followed a lead compound through in vitro and in vivo characterisation. Results: We identified several known antimicrobial compound classes with antibacterial activity against Shigella. These compounds included the oral carbapenem Tebipenem, which was found to be highly potent against broadly susceptible Shigella and contemporary MDR variants for which we perform detailed pre-clinical testing. Additional in vitro screening demonstrated that Tebipenem had activity against a wide range of other non-Shigella enteric bacteria. Cognisant of the risk for the development of resistance against monotherapy, we identified synergistic behaviour of two different drug combinations incorporating Tebipenem. We found the orally bioavailable prodrug (Tebipenem pivoxil) had ideal pharmacokinetic properties for treating enteric pathogens and was effective in clearing the gut of infecting organisms when administered to Shigella-infected mice and gnotobiotic piglets. Conclusions: Our data highlight the emerging antimicrobial resistance crisis and shows that Tebipenem pivoxil (licenced for paediatric respiratory tract infections in Japan) should be accelerated into human trials and could be repurposed as an effective treatment for severe diarrhoea caused by MDR Shigella and other enteric pathogens in LMICs. Funding: Tres Cantos Open Lab Foundation (projects TC239 and TC246), the Bill and Melinda Gates Foundation (grant OPP1172483) and Wellcome (215515/Z/19/Z).
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Affiliation(s)
| | - Phat Voong Vinh
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Viet Nam
| | | | | | | | | | | | - Nhu Tran Do Hoang
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Viet Nam
| | - Tuyen Ha Thanh
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Viet Nam
| | - Molly McCloskey
- Division of Allergy and Infectious Disease, Center for Emerging and Re-emerging Infectious Diseases, University of Washington School of Medicine, Seattle, United States
| | - Shareef Shaheen
- Division of Allergy and Infectious Disease, Center for Emerging and Re-emerging Infectious Diseases, University of Washington School of Medicine, Seattle, United States
| | - Denise Dayao
- Department of Infectious Disease and Global Health, Tufts University, North Grafton, United States
| | | | | | | | - Benson Singa
- Kenya Medical Research Institute, Nairobi, Kenya
| | - Patricia Pavlinac
- Department of Global Health, University of Washington, Seattle, United States
| | - Judd Walson
- Division of Allergy and Infectious Disease, Center for Emerging and Re-emerging Infectious Diseases, University of Washington School of Medicine, Seattle, United States
| | | | - Samuel L M Arnold
- Division of Allergy and Infectious Disease, Center for Emerging and Re-emerging Infectious Diseases, University of Washington School of Medicine, Seattle, United States
| | - Tzipori Saul
- Department of Infectious Disease and Global Health, Tufts University, North Grafton, United States
| | | | - Stephen Baker
- Department of Medicine, University of Cambridge, Cambridge, United Kingdom
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6
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Mai SNT, Bodhidatta L, Turner P, Wangchuk S, Ha Thanh T, Voong Vinh P, Pham DT, Rabaa MA, Thwaites GE, Thomson NR, Baker S, Chung The H. The evolutionary history of Shigella flexneri serotype 6 in Asia. Microb Genom 2021; 7. [PMID: 34904947 PMCID: PMC8767353 DOI: 10.1099/mgen.0.000736] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Shigella flexneri serotype 6 is an understudied cause of diarrhoeal diseases in developing countries, and has been proposed as one of the major targets for vaccine development against shigellosis. Despite being named as S. flexneri, Shigella flexneri serotype 6 is phylogenetically distinct from other S. flexneri serotypes and more closely related to S. boydii. This unique phylogenetic relationship and its low sampling frequency have hampered genomic research on this pathogen. Herein, by utilizing whole genome sequencing (WGS) and analyses of Shigella flexneri serotype 6 collected from epidemiological studies (1987–2013) in four Asian countries, we revealed its population structure and evolutionary history in the region. Phylogenetic analyses supported the delineation of Asian Shigella flexneri serotype 6 into two phylogenetic groups (PG-1 and −2). Notably, temporal phylogenetic approaches showed that extant Asian S. flexneri serotype 6 could be traced back to an inferred common ancestor arising in the 18th century. The dominant lineage PG-1 likely emerged in the 1970s, which coincided with the times to most recent common ancestors (tMRCAs) inferred from other major Southeast Asian S. flexneri serotypes. Similar to other S. flexneri serotypes in the same period in Asia, genomic analyses showed that resistance to first-generation antimicrobials was widespread, while resistance to more recent first-line antimicrobials was rare. These data also showed a number of gene inactivation and gene loss events, particularly on genes related to metabolism and synthesis of cellular appendages, emphasizing the continuing role of reductive evolution in the adaptation of the pathogen to an intracellular lifestyle. Together, our findings reveal insights into the genomic evolution of the understudied Shigella flexneri serotype 6, providing a new piece in the puzzle of Shigella epidemiology and evolution.
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Affiliation(s)
- Si-Nguyen T Mai
- Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam.,Groningen Institute for Evolutionary Life Sciences, University of Groningen, Groningen, The Netherlands
| | | | - Paul Turner
- Cambodia-Oxford Medical Research Unit, Angkor Hospital for Children, Siem Reap, Cambodia.,Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK
| | - Sonam Wangchuk
- Royal Centre for Disease Control, Ministry of Health, Thimphu, Bhutan
| | - Tuyen Ha Thanh
- Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
| | - Phat Voong Vinh
- Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
| | - Duy Thanh Pham
- Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam.,Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK
| | - Maia A Rabaa
- Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam.,Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK
| | - Guy E Thwaites
- Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam.,Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK
| | - Nicholas R Thomson
- The Wellcome Trust Sanger Institute, Hinxton, Cambridge, UK.,London School of Hygiene and Tropical Medicine, Bloomsbury, London WC1E 7HT, UK
| | - Stephen Baker
- Department of Medicine, Cambridge Institute of Therapeutic Immunology and Infectious Diseases (CITIID), University of Cambridge, Cambridge, UK
| | - Hao Chung The
- Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
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7
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Mylona E, Voong Vinh P, Qureshi S, Karkey A, Dongol S, Ha Thanh T, Walson J, Ballell L, Fernández Álvaro E, Qamar F, Baker S. Tebipenem as an oral alternative for the treatment of typhoid caused by XDR Salmonella Typhi. J Antimicrob Chemother 2021; 76:3197-3200. [PMID: 34534310 PMCID: PMC8598285 DOI: 10.1093/jac/dkab326] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Accepted: 08/05/2021] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Antimicrobial therapy is essential for the treatment of enteric fever, the infection caused by Salmonella serovars Typhi and Paratyphi A. However, an increase in resistance to key antimicrobials and the emergence of MDR and XDR in Salmonella Typhi poses a major threat for efficacious outpatient treatments. OBJECTIVES We recently identified tebipenem, an oral carbapenem licensed for use for respiratory tract infections in Japan, as a potential alternative treatment for MDR/XDR Shigella spp. Here, we aimed to test the in vitro antibacterial efficacy of this drug against MDR and XDR typhoidal Salmonella. METHODS We determined the in vitro activity of tebipenem in time-kill assays against a collection of non-XDR and XDR Salmonella Typhi and Salmonella Paratyphi A (non-XDR) isolated in Nepal and Bangladesh. We also tested the efficacy of tebipenem in combination with other antimicrobials. RESULTS We found that both XDR and non-XDR Salmonella Typhi and Salmonella Paratyphi A are susceptible to tebipenem, exhibiting low MICs, and were killed within 8-24 h at 2-4×MIC. Additionally, tebipenem demonstrated synergy with two other antimicrobials and could efficiently induce bacterial killing. CONCLUSIONS Salmonella Paratyphi A and XDR Salmonella Typhi display in vitro susceptibility to the oral carbapenem tebipenem, while synergistic activity with other antimicrobials may limit the emergence of resistance. The broad-spectrum activity of this drug against MDR/XDR organisms renders tebipenem a good candidate for clinical trials.
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Affiliation(s)
- Elli Mylona
- University of Cambridge School of Clinical Medicine, Cambridge Biomedical Campus, Cambridge, UK.,Department of Medicine, University of Cambridge School of Clinical Medicine, Cambridge Biomedical Campus, Cambridge, UK
| | - Phat Voong Vinh
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
| | | | - Abhilasha Karkey
- Nepal Academy of Health Sciences, Oxford University Clinical Research Unit, Kathmandu, Nepal
| | - Sabina Dongol
- Nepal Academy of Health Sciences, Oxford University Clinical Research Unit, Kathmandu, Nepal
| | - Tuyen Ha Thanh
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
| | - Judd Walson
- Division of Allergy and Infectious Disease, Center for Emerging and Re-emerging Infectious Diseases, University of Washington School of Medicine, Seattle, WA, USA
| | | | | | | | - Stephen Baker
- University of Cambridge School of Clinical Medicine, Cambridge Biomedical Campus, Cambridge, UK.,Department of Medicine, University of Cambridge School of Clinical Medicine, Cambridge Biomedical Campus, Cambridge, UK
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8
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Chung The H, Bodhidatta L, Pham DT, Mason CJ, Ha Thanh T, Voong Vinh P, Turner P, Hem S, Dance DAB, Newton PN, Phetsouvanh R, Davong V, Thwaites GE, Thomson NR, Baker S, Rabaa MA. Evolutionary histories and antimicrobial resistance in Shigella flexneri and Shigella sonnei in Southeast Asia. Commun Biol 2021; 4:353. [PMID: 33742111 PMCID: PMC7979695 DOI: 10.1038/s42003-021-01905-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Accepted: 02/10/2021] [Indexed: 01/31/2023] Open
Abstract
Conventional disease surveillance for shigellosis in developing country settings relies on serotyping and low-resolution molecular typing, which fails to contextualise the evolutionary history of the genus. Here, we interrogated a collection of 1,804 Shigella whole genome sequences from organisms isolated in four continental Southeast Asian countries (Thailand, Vietnam, Laos, and Cambodia) over three decades to characterise the evolution of both S. flexneri and S. sonnei. We show that S. sonnei and each major S. flexneri serotype are comprised of genetically diverse populations, the majority of which were likely introduced into Southeast Asia in the 1970s-1990s. Intranational and regional dissemination allowed widespread propagation of both species across the region. Our data indicate that the epidemiology of S. sonnei and the major S. flexneri serotypes were characterised by frequent clonal replacement events, coinciding with changing susceptibility patterns against contemporaneous antimicrobials. We conclude that adaptation to antimicrobial pressure was pivotal to the recent evolutionary trajectory of Shigella in Southeast Asia.
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Affiliation(s)
- Hao Chung The
- grid.412433.30000 0004 0429 6814Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
| | - Ladaporn Bodhidatta
- grid.413910.e0000 0004 0419 1772Department of Enteric Diseases, Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand
| | - Duy Thanh Pham
- grid.412433.30000 0004 0429 6814Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam ,grid.4991.50000 0004 1936 8948Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK
| | - Carl J. Mason
- grid.413910.e0000 0004 0419 1772Department of Enteric Diseases, Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand
| | - Tuyen Ha Thanh
- grid.412433.30000 0004 0429 6814Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
| | - Phat Voong Vinh
- grid.412433.30000 0004 0429 6814Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
| | - Paul Turner
- grid.4991.50000 0004 1936 8948Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK ,grid.459332.a0000 0004 0418 5364Cambodia-Oxford Medical Research Unit, Angkor Hospital for Children, Siem Reap, Cambodia
| | - Sopheak Hem
- grid.418537.cMedical Biology Unit, Institut Pasteur du Cambodge, Institut Pasteur International Network, Phnom Penh, Cambodia
| | - David A. B. Dance
- grid.4991.50000 0004 1936 8948Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK ,grid.416302.20000 0004 0484 3312Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit, Microbiology Laboratory, Mahosot Hospital, Vientiane, Laos ,grid.8991.90000 0004 0425 469XLondon School of Hygiene and Tropical Medicine, London, UK
| | - Paul N. Newton
- grid.4991.50000 0004 1936 8948Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK ,grid.416302.20000 0004 0484 3312Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit, Microbiology Laboratory, Mahosot Hospital, Vientiane, Laos ,grid.8991.90000 0004 0425 469XLondon School of Hygiene and Tropical Medicine, London, UK
| | - Rattanaphone Phetsouvanh
- grid.4991.50000 0004 1936 8948Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK ,grid.416302.20000 0004 0484 3312Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit, Microbiology Laboratory, Mahosot Hospital, Vientiane, Laos
| | - Viengmon Davong
- grid.416302.20000 0004 0484 3312Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit, Microbiology Laboratory, Mahosot Hospital, Vientiane, Laos
| | - Guy E. Thwaites
- grid.412433.30000 0004 0429 6814Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam ,grid.4991.50000 0004 1936 8948Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK
| | - Nicholas R. Thomson
- grid.8991.90000 0004 0425 469XLondon School of Hygiene and Tropical Medicine, London, UK ,grid.10306.340000 0004 0606 5382The Wellcome Trust Sanger Institute, Hinxton, Cambridge, UK
| | - Stephen Baker
- grid.5335.00000000121885934The Department of Medicine, University of Cambridge, Cambridge, UK
| | - Maia A. Rabaa
- grid.412433.30000 0004 0429 6814Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam ,grid.4991.50000 0004 1936 8948Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK
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Thuy DB, Campbell J, Thuy CT, Hoang NVM, Voong Vinh P, Nguyen TNT, Nguyen Ngoc Minh C, Pham DT, Rabaa MA, Lan NPH, Hao NV, Thwaites GE, Thwaites CL, Baker S, Chau NVV, Chung The H. Colonization with Staphylococcus aureus and Klebsiella pneumoniae causes infections in a Vietnamese intensive care unit. Microb Genom 2021; 7:000514. [PMID: 33502303 PMCID: PMC8208697 DOI: 10.1099/mgen.0.000514] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Accepted: 12/21/2020] [Indexed: 12/26/2022] Open
Abstract
Pre-existing colonization with Staphylococcus aureus or Klebsiella pneumoniae has been found to increase the risk of infection in intensive care patients. We previously conducted a longitudinal study to characterize colonization of these two organisms in patients admitted to intensive care in a hospital in southern Vietnam. Here, using genomic and phylogenetic analyses, we aimed to assess the contribution these colonizing organisms made to infections. We found that in the majority of patients infected with S. aureus or K. pneumoniae, the sequence type of the disease-causing (infecting) isolate was identical to that of corresponding colonizing organisms in the respective patient. Further in-depth analysis revealed that in patients infected by S. aureus ST188 and by K. pneumoniae ST17, ST23, ST25 and ST86, the infecting isolate was closely related to and exhibited limited genetic variation relative to pre-infection colonizing isolates. Multidrug-resistant S. aureus ST188 was identified as the predominant agent of colonization and infection. Colonization and infection by K. pneumoniae were characterized by organisms with limited antimicrobial resistance profiles but extensive repertoires of virulence genes. Our findings augment the understanding of the link between bacterial colonization and infection in a low-resource setting, and could facilitate the development of novel evidence-based approaches to prevent and treat infections in high-risk patients in intensive care.
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Affiliation(s)
- Duong Bich Thuy
- The Hospital for Tropical Diseases, Ho Chi Minh City, Vietnam
| | - James Campbell
- Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
- Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, Oxford University, Oxford, UK
| | - Cao Thu Thuy
- Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
| | | | - Phat Voong Vinh
- Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
| | | | | | - Duy Thanh Pham
- Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
- Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, Oxford University, Oxford, UK
| | - Maia A. Rabaa
- Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
- Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, Oxford University, Oxford, UK
| | | | - Nguyen Van Hao
- The Hospital for Tropical Diseases, Ho Chi Minh City, Vietnam
| | - Guy E. Thwaites
- Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
- Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, Oxford University, Oxford, UK
| | - C. Louise Thwaites
- Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
- Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, Oxford University, Oxford, UK
| | - Stephen Baker
- Cambridge Institute of Therapeutic Immunology & Infectious Disease (CITIID), University of Cambridge, Cambridge, UK
| | | | - Hao Chung The
- Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
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Robertson G, Perry M, Vinh PV, Ngoc DTT, Thanh TPT, My PT, Thao HD, Rabaa M, Baker S, Woolhouse M. Pig Exposure and Health Outcomes in Hospitalized Infectious Disease Patients in Vietnam. Ecohealth 2020; 17:28-40. [PMID: 31845120 PMCID: PMC7109191 DOI: 10.1007/s10393-019-01460-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/15/2018] [Accepted: 10/31/2019] [Indexed: 06/10/2023]
Abstract
Many infectious diseases have a zoonotic origin, and several have had major public health implications. Contact with animals is a known risk factor for zoonotic infections, although there are limited data on disease symptoms and pathogens associated with contact with different animal species. The rise in pig production in Southeast Asia has contributed to the emergence and re-emergence of zoonotic infections caused by contact with pigs and pig products. To compare the symptom and pathogen profiles of hospitalized patients with and without pig contact, we collected data on disease symptoms, infecting pathogens, and animal contact behaviour from patients attending six hospitals across Vietnam between 2012 and 2016. Patients who had previous contact with pigs were more likely to have enteric disease than respiratory or central nervous system infections and were more likely to grow Escherichia coli and Shigella from stool culture than those without pig contact. Patients with enteric infections who kept pigs were also more likely to have a disease of unknown origin. Public health initiatives that account for differences in animal contact behaviours and offer more comprehensive diagnostics in high-risk individuals are needed if emergence and re-emergence of zoonotic disease is to be monitored and prevented.
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Affiliation(s)
- Gail Robertson
- School of Mathematics, James Clerk Maxwell Building, King's Buildings, University of Edinburgh, Edinburgh, UK.
| | - Meghan Perry
- Epidemiology Research Group, King's Buildings, University of Edinburgh, Edinburgh, UK
| | - Phat Voong Vinh
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
| | - Dung Tran Thi Ngoc
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
| | - Tam Pham Thi Thanh
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
| | - Phuc Tran My
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
| | - Huong Dang Thao
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
| | - Maia Rabaa
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
- Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, Oxford University, Oxford, UK
| | - Stephen Baker
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
- Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, Oxford University, Oxford, UK
| | - Mark Woolhouse
- Usher Institute of Population Health Sciences and Informatics, Ashworth Laboratories, King's Buildings, University of Edinburgh, Edinburgh, UK
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11
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Wyres KL, Nguyen TNT, Lam MMC, Judd LM, van Vinh Chau N, Dance DAB, Ip M, Karkey A, Ling CL, Miliya T, Newton PN, Lan NPH, Sengduangphachanh A, Turner P, Veeraraghavan B, Vinh PV, Vongsouvath M, Thomson NR, Baker S, Holt KE. Genomic surveillance for hypervirulence and multi-drug resistance in invasive Klebsiella pneumoniae from South and Southeast Asia. Genome Med 2020; 12:11. [PMID: 31948471 DOI: 10.1101/557785v1.full] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Accepted: 12/12/2019] [Indexed: 05/26/2023] Open
Abstract
BACKGROUND Klebsiella pneumoniae is a leading cause of bloodstream infection (BSI). Strains producing extended-spectrum beta-lactamases (ESBLs) or carbapenemases are considered global priority pathogens for which new treatment and prevention strategies are urgently required, due to severely limited therapeutic options. South and Southeast Asia are major hubs for antimicrobial-resistant (AMR) K. pneumoniae and also for the characteristically antimicrobial-sensitive, community-acquired "hypervirulent" strains. The emergence of hypervirulent AMR strains and lack of data on exopolysaccharide diversity pose a challenge for K. pneumoniae BSI control strategies worldwide. METHODS We conducted a retrospective genomic epidemiology study of 365 BSI K. pneumoniae from seven major healthcare facilities across South and Southeast Asia, extracting clinically relevant information (AMR, virulence, K and O antigen loci) using Kleborate, a K. pneumoniae-specific genomic typing tool. RESULTS K. pneumoniae BSI isolates were highly diverse, comprising 120 multi-locus sequence types (STs) and 63 K-loci. ESBL and carbapenemase gene frequencies were 47% and 17%, respectively. The aerobactin synthesis locus (iuc), associated with hypervirulence, was detected in 28% of isolates. Importantly, 7% of isolates harboured iuc plus ESBL and/or carbapenemase genes. The latter represent genotypic AMR-virulence convergence, which is generally considered a rare phenomenon but was particularly common among South Asian BSI (17%). Of greatest concern, we identified seven novel plasmids carrying both iuc and AMR genes, raising the prospect of co-transfer of these phenotypes among K. pneumoniae. CONCLUSIONS K. pneumoniae BSI in South and Southeast Asia are caused by different STs from those predominating in other regions, and with higher frequency of acquired virulence determinants. K. pneumoniae carrying both iuc and AMR genes were also detected at higher rates than have been reported elsewhere. The study demonstrates how genomics-based surveillance-reporting full molecular profiles including STs, AMR, virulence and serotype locus information-can help standardise comparisons between sites and identify regional differences in pathogen populations.
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Affiliation(s)
- Kelly L Wyres
- Department of Infectious Diseases, Central Clinical School, Monash University, Melbourne, Victoria, 3004, Australia
| | - To N T Nguyen
- Hospital of Tropical Diseases, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
| | - Margaret M C Lam
- Department of Infectious Diseases, Central Clinical School, Monash University, Melbourne, Victoria, 3004, Australia
| | - Louise M Judd
- Department of Infectious Diseases, Central Clinical School, Monash University, Melbourne, Victoria, 3004, Australia
| | | | - David A B Dance
- Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit, Microbiology Laboratory, Mahosot Hospital, Vientiane, Lao People's Democratic Republic
- Centre for Tropical Medicine and Global Health, University of Oxford, Oxford, UK
- London School of Hygiene and Tropical Medicine, London, UK
| | - Margaret Ip
- Department of Microbiology, The Chinese University of Hong Kong, Hong Kong Special Administrative Region, China
| | - Abhilasha Karkey
- Centre for Tropical Medicine and Global Health, University of Oxford, Oxford, UK
- Patan Academy of Health Sciences, Oxford University Clinical Research Unit, Kathmandu, Nepal
| | - Clare L Ling
- Centre for Tropical Medicine and Global Health, University of Oxford, Oxford, UK
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, 63110, Thailand
| | - Thyl Miliya
- Cambodia Oxford Medical Research Unit, Angkor Hospital for Children, Siem Reap, Cambodia
| | - Paul N Newton
- Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit, Microbiology Laboratory, Mahosot Hospital, Vientiane, Lao People's Democratic Republic
- Centre for Tropical Medicine and Global Health, University of Oxford, Oxford, UK
- London School of Hygiene and Tropical Medicine, London, UK
| | | | - Amphone Sengduangphachanh
- Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit, Microbiology Laboratory, Mahosot Hospital, Vientiane, Lao People's Democratic Republic
| | - Paul Turner
- Centre for Tropical Medicine and Global Health, University of Oxford, Oxford, UK
- Cambodia Oxford Medical Research Unit, Angkor Hospital for Children, Siem Reap, Cambodia
| | - Balaji Veeraraghavan
- Department of Clinical Microbiology, Christian Medical College, Vellore, Tamil Nadu, India
| | - Phat Voong Vinh
- Hospital of Tropical Diseases, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
| | - Manivanh Vongsouvath
- Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit, Microbiology Laboratory, Mahosot Hospital, Vientiane, Lao People's Democratic Republic
| | - Nicholas R Thomson
- London School of Hygiene and Tropical Medicine, London, UK
- Wellcome Trust Sanger Institute, Hinxton, Cambridge, UK
| | - Stephen Baker
- Cambridge Institute of Therapeutic Immunology & Infectious Disease (CITIID) Department of Medicine, University of Cambridge, Cambridge Biomedical Campus, Cambridge, CB2 0AW, UK.
| | - Kathryn E Holt
- Department of Infectious Diseases, Central Clinical School, Monash University, Melbourne, Victoria, 3004, Australia
- London School of Hygiene and Tropical Medicine, London, UK
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12
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Wyres KL, Nguyen TNT, Lam MMC, Judd LM, van Vinh Chau N, Dance DAB, Ip M, Karkey A, Ling CL, Miliya T, Newton PN, Lan NPH, Sengduangphachanh A, Turner P, Veeraraghavan B, Vinh PV, Vongsouvath M, Thomson NR, Baker S, Holt KE. Genomic surveillance for hypervirulence and multi-drug resistance in invasive Klebsiella pneumoniae from South and Southeast Asia. Genome Med 2020; 12:11. [PMID: 31948471 PMCID: PMC6966826 DOI: 10.1186/s13073-019-0706-y] [Citation(s) in RCA: 144] [Impact Index Per Article: 36.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Accepted: 12/12/2019] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND Klebsiella pneumoniae is a leading cause of bloodstream infection (BSI). Strains producing extended-spectrum beta-lactamases (ESBLs) or carbapenemases are considered global priority pathogens for which new treatment and prevention strategies are urgently required, due to severely limited therapeutic options. South and Southeast Asia are major hubs for antimicrobial-resistant (AMR) K. pneumoniae and also for the characteristically antimicrobial-sensitive, community-acquired "hypervirulent" strains. The emergence of hypervirulent AMR strains and lack of data on exopolysaccharide diversity pose a challenge for K. pneumoniae BSI control strategies worldwide. METHODS We conducted a retrospective genomic epidemiology study of 365 BSI K. pneumoniae from seven major healthcare facilities across South and Southeast Asia, extracting clinically relevant information (AMR, virulence, K and O antigen loci) using Kleborate, a K. pneumoniae-specific genomic typing tool. RESULTS K. pneumoniae BSI isolates were highly diverse, comprising 120 multi-locus sequence types (STs) and 63 K-loci. ESBL and carbapenemase gene frequencies were 47% and 17%, respectively. The aerobactin synthesis locus (iuc), associated with hypervirulence, was detected in 28% of isolates. Importantly, 7% of isolates harboured iuc plus ESBL and/or carbapenemase genes. The latter represent genotypic AMR-virulence convergence, which is generally considered a rare phenomenon but was particularly common among South Asian BSI (17%). Of greatest concern, we identified seven novel plasmids carrying both iuc and AMR genes, raising the prospect of co-transfer of these phenotypes among K. pneumoniae. CONCLUSIONS K. pneumoniae BSI in South and Southeast Asia are caused by different STs from those predominating in other regions, and with higher frequency of acquired virulence determinants. K. pneumoniae carrying both iuc and AMR genes were also detected at higher rates than have been reported elsewhere. The study demonstrates how genomics-based surveillance-reporting full molecular profiles including STs, AMR, virulence and serotype locus information-can help standardise comparisons between sites and identify regional differences in pathogen populations.
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Affiliation(s)
- Kelly L Wyres
- Department of Infectious Diseases, Central Clinical School, Monash University, Melbourne, Victoria, 3004, Australia
| | - To N T Nguyen
- Hospital of Tropical Diseases, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
| | - Margaret M C Lam
- Department of Infectious Diseases, Central Clinical School, Monash University, Melbourne, Victoria, 3004, Australia
| | - Louise M Judd
- Department of Infectious Diseases, Central Clinical School, Monash University, Melbourne, Victoria, 3004, Australia
| | | | - David A B Dance
- Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit, Microbiology Laboratory, Mahosot Hospital, Vientiane, Lao People's Democratic Republic
- Centre for Tropical Medicine and Global Health, University of Oxford, Oxford, UK
- London School of Hygiene and Tropical Medicine, London, UK
| | - Margaret Ip
- Department of Microbiology, The Chinese University of Hong Kong, Hong Kong Special Administrative Region, China
| | - Abhilasha Karkey
- Centre for Tropical Medicine and Global Health, University of Oxford, Oxford, UK
- Patan Academy of Health Sciences, Oxford University Clinical Research Unit, Kathmandu, Nepal
| | - Clare L Ling
- Centre for Tropical Medicine and Global Health, University of Oxford, Oxford, UK
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, 63110, Thailand
| | - Thyl Miliya
- Cambodia Oxford Medical Research Unit, Angkor Hospital for Children, Siem Reap, Cambodia
| | - Paul N Newton
- Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit, Microbiology Laboratory, Mahosot Hospital, Vientiane, Lao People's Democratic Republic
- Centre for Tropical Medicine and Global Health, University of Oxford, Oxford, UK
- London School of Hygiene and Tropical Medicine, London, UK
| | | | - Amphone Sengduangphachanh
- Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit, Microbiology Laboratory, Mahosot Hospital, Vientiane, Lao People's Democratic Republic
| | - Paul Turner
- Centre for Tropical Medicine and Global Health, University of Oxford, Oxford, UK
- Cambodia Oxford Medical Research Unit, Angkor Hospital for Children, Siem Reap, Cambodia
| | - Balaji Veeraraghavan
- Department of Clinical Microbiology, Christian Medical College, Vellore, Tamil Nadu, India
| | - Phat Voong Vinh
- Hospital of Tropical Diseases, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
| | - Manivanh Vongsouvath
- Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit, Microbiology Laboratory, Mahosot Hospital, Vientiane, Lao People's Democratic Republic
| | - Nicholas R Thomson
- London School of Hygiene and Tropical Medicine, London, UK
- Wellcome Trust Sanger Institute, Hinxton, Cambridge, UK
| | - Stephen Baker
- Cambridge Institute of Therapeutic Immunology & Infectious Disease (CITIID) Department of Medicine, University of Cambridge, Cambridge Biomedical Campus, Cambridge, CB2 0AW, UK.
| | - Kathryn E Holt
- Department of Infectious Diseases, Central Clinical School, Monash University, Melbourne, Victoria, 3004, Australia
- London School of Hygiene and Tropical Medicine, London, UK
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13
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Chau TTH, Chau NNM, Le NTH, The HC, Vinh PV, To NTN, Ngoc NM, Tuan HM, Ngoc TLC, Kolader ME, Farrar JJ, Wolbers M, Thwaites GE, Baker S. A Double-blind, Randomized, Placebo-controlled Trial of Lactobacillus acidophilus for the Treatment of Acute Watery Diarrhea in Vietnamese Children. Pediatr Infect Dis J 2018; 37:35-42. [PMID: 28787388 PMCID: PMC5681247 DOI: 10.1097/inf.0000000000001712] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
BACKGROUND Probiotics are the most frequently prescribed treatment for children hospitalized with diarrhea in Vietnam. We were uncertain of the benefits of probiotics for the treatment of acute watery diarrhea in Vietnamese children. METHODS We conducted a double-blind, placebo-controlled, randomized trial of children hospitalized with acute watery diarrhea in Vietnam. Children meeting the inclusion criteria (acute watery diarrhea) were randomized to receive either 2 daily oral doses of 2 × 10 CFUs of a local probiotic containing Lactobacillus acidophilus or placebo for 5 days as an adjunct to standard of care. The primary end point was time from the first dose of study medication to the start of the first 24-hour period without diarrhea. Secondary outcomes included the total duration of diarrhea and hospitalization, daily stool frequency, treatment failure, daily fecal concentrations of rotavirus and norovirus, and Lactobacillus colonization. RESULTS One hundred and fifty children were randomized into each study group. The median time from the first dose of study medication to the start of the first 24-hour diarrhea-free period was 43 hours (interquartile range, 15-66 hours) in the placebo group and 35 hours (interquartile range, 20-68 hours) in the probiotic group (acceleration factor 1.09 [95% confidence interval, 0.78-1.51]; P = 0.62). There was also no evidence that probiotic treatment was efficacious in any of the predefined subgroups nor significantly associated with any secondary end point. CONCLUSIONS This was a large double-blind, placebo-controlled trial in which the probiotic underwent longitudinal quality control. We found under these conditions that L. acidophilus was not beneficial in treating children with acute watery diarrhea.
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Affiliation(s)
- Tran Thi Hong Chau
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
| | - Nguyen Ngoc Minh Chau
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
| | - Nhat Thanh Hoang Le
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
| | - Hao Chung The
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
| | - Phat Voong Vinh
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
| | - Nguyen Thi Nguyen To
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
| | | | - Ha Manh Tuan
- Children’s Hospital 2 (CH2), Ho Chi Minh City, Vietnam
| | | | | | - Jeremy J. Farrar
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam,Centre for Tropical Medicine, Oxford University, Oxford, United Kingdom
| | - Marcel Wolbers
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam,Centre for Tropical Medicine, Oxford University, Oxford, United Kingdom
| | - Guy E. Thwaites
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam,Centre for Tropical Medicine, Oxford University, Oxford, United Kingdom
| | - Stephen Baker
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam,Centre for Tropical Medicine, Oxford University, Oxford, United Kingdom,The Department of Medicine, The University of Cambridge, Cambridge, United Kingdom,Corresponding Author: Professor Stephen Baker, the Hospital for Tropical Diseases, 764 Vo Van Kiet, Quan 5, Ho Chi Minh City, Vietnam. Tel: +84 89241761; Fax: +84 89238904;
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14
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Tran Vu Thieu N, Trinh Van T, Tran Tuan A, Klemm EJ, Nguyen Ngoc Minh C, Voong Vinh P, Pham Thanh D, Ho Ngoc Dan T, Pham Duc T, Langat P, Martin LB, Galan J, Liang L, Felgner PL, Davies DH, de Jong HK, Maude RR, Fukushima M, Wijedoru L, Ghose A, Samad R, Dondorp AM, Faiz A, Darton TC, Pollard AJ, Thwaites GE, Dougan G, Parry CM, Baker S. An evaluation of purified Salmonella Typhi protein antigens for the serological diagnosis of acute typhoid fever. J Infect 2017; 75:104-114. [PMID: 28551371 PMCID: PMC5522525 DOI: 10.1016/j.jinf.2017.05.007] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2017] [Revised: 05/15/2017] [Accepted: 05/16/2017] [Indexed: 12/14/2022]
Abstract
Objectives The diagnosis of typhoid fever is a challenge. Aiming to develop a typhoid diagnostic we measured antibody responses against Salmonella Typhi (S. Typhi) protein antigens and the Vi polysaccharide in a cohort of Bangladeshi febrile patients. Methods IgM against 12 purified antigens and the Vi polysaccharide was measured by ELISA in plasma from patients with confirmed typhoid fever (n = 32), other confirmed infections (n = 17), and healthy controls (n = 40). ELISAs with the most specific antigens were performed on plasma from 243 patients with undiagnosed febrile disease. Results IgM against the S. Typhi protein antigens correlated with each other (rho > 0.8), but not against Vi (rho < 0.6). Typhoid patients exhibited higher IgM against 11/12 protein antigens and Vi than healthy controls and those with other infections. Vi, PilL, and CdtB exhibited the greatest sensitivity and specificity. Specificity and sensitivity was improved when Vi was combined with a protein antigen, generating sensitivities and specificities of 0.80 and >0.85, respectively. Applying a dynamic cut-off to patients with undiagnosed febrile disease suggested that 34–58% had an IgM response indicative of typhoid. Conclusions We evaluated the diagnostic potential of several S. Typhi antigens; our assays give good sensitivity and specificity, but require further assessment in differing patient populations.
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Affiliation(s)
- Nga Tran Vu Thieu
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Viet Nam
| | - Tan Trinh Van
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Viet Nam
| | - Anh Tran Tuan
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Viet Nam
| | - Elizabeth J Klemm
- The Wellcome Trust Sanger Institute, Hinxton, Cambridgeshire, United Kingdom
| | - Chau Nguyen Ngoc Minh
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Viet Nam
| | - Phat Voong Vinh
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Viet Nam
| | - Duy Pham Thanh
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Viet Nam
| | - Thanh Ho Ngoc Dan
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Viet Nam
| | - Trung Pham Duc
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Viet Nam
| | - Pinky Langat
- The Wellcome Trust Sanger Institute, Hinxton, Cambridgeshire, United Kingdom
| | - Laura B Martin
- Sclavo Berhing Vaccines Institute for Global Health, Siena, Italy
| | - Jorge Galan
- Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, CT, USA
| | - Li Liang
- Department of Medicine, Division of Infectious Diseases, University of California, Irvine, CA, USA
| | - Philip L Felgner
- Department of Medicine, Division of Infectious Diseases, University of California, Irvine, CA, USA
| | - D Huw Davies
- Department of Medicine, Division of Infectious Diseases, University of California, Irvine, CA, USA
| | - Hanna K de Jong
- Department of Internal Medicine, Division of Infectious Diseases and Center for Infection and Immunity Amsterdam (CINIMA), Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Rapeephan R Maude
- Mahidol-Oxford Tropical Medicine Research Unit (MORU), Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand; Centre for Tropical Medicine and Global Health, Oxford University, Oxford, United Kingdom
| | - Masako Fukushima
- Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Lalith Wijedoru
- Mahidol-Oxford Tropical Medicine Research Unit (MORU), Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | | | - Rasheda Samad
- Chittagong Medical College Hospital, Chittagong, Bangladesh
| | - Arjen M Dondorp
- Mahidol-Oxford Tropical Medicine Research Unit (MORU), Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand; Malaria Research Group and Dev Care Foundation, Bangladesh
| | - Abul Faiz
- Malaria Research Group and Dev Care Foundation, Bangladesh
| | - Thomas C Darton
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Viet Nam; Sheffield Teaching Hospitals NHS Trust Foundation and the University of Sheffield, Sheffield, United Kingdom
| | - Andrew J Pollard
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford and the NIHR Oxford Biomedical Research Centre, Oxford, United Kingdom
| | - Guy E Thwaites
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Viet Nam; Centre for Tropical Medicine and Global Health, Oxford University, Oxford, United Kingdom
| | - Gordon Dougan
- The Wellcome Trust Sanger Institute, Hinxton, Cambridgeshire, United Kingdom; The Department of Medicine, University of Cambridge, Cambridge, United Kingdom
| | - Christopher M Parry
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford and the NIHR Oxford Biomedical Research Centre, Oxford, United Kingdom
| | - Stephen Baker
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Viet Nam; Centre for Tropical Medicine and Global Health, Oxford University, Oxford, United Kingdom; The Department of Medicine, University of Cambridge, Cambridge, United Kingdom.
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15
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Dyson ZA, Thanh DP, Bodhidatta L, Mason CJ, Srijan A, Rabaa MA, Vinh PV, Thanh TH, Thwaites GE, Baker S, Holt KE. Whole Genome Sequence Analysis of Salmonella Typhi Isolated in Thailand before and after the Introduction of a National Immunization Program. PLoS Negl Trop Dis 2017; 11:e0005274. [PMID: 28060810 PMCID: PMC5245908 DOI: 10.1371/journal.pntd.0005274] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2016] [Revised: 01/19/2017] [Accepted: 12/20/2016] [Indexed: 12/31/2022] Open
Abstract
Vaccines against Salmonella Typhi, the causative agent of typhoid fever, are commonly used by travellers, however, there are few examples of national immunization programs in endemic areas. There is therefore a paucity of data on the impact of typhoid immunization programs on localised populations of S. Typhi. Here we have used whole genome sequencing (WGS) to characterise 44 historical bacterial isolates collected before and after a national typhoid immunization program that was implemented in Thailand in 1977 in response to a large outbreak; the program was highly effective in reducing typhoid case numbers. Thai isolates were highly diverse, including 10 distinct phylogenetic lineages or genotypes. Novel prophage and plasmids were also detected, including examples that were previously only reported in Shigella sonnei and Escherichia coli. The majority of S. Typhi genotypes observed prior to the immunization program were not observed following it. Post-vaccine era isolates were more closely related to S. Typhi isolated from neighbouring countries than to earlier Thai isolates, providing no evidence for the local persistence of endemic S. Typhi following the national immunization program. Rather, later cases of typhoid appeared to be caused by the occasional importation of common genotypes from neighbouring Vietnam, Laos, and Cambodia. These data show the value of WGS in understanding the impacts of vaccination on pathogen populations and provide support for the proposal that large-scale typhoid immunization programs in endemic areas could result in lasting local disease elimination, although larger prospective studies are needed to test this directly. Typhoid fever is a systemic infection caused by the bacterium Salmonella Typhi. Typhoid fever is associated with inadequate hygiene in low-income settings and a lack of sanitation infrastructure. A sustained outbreak of typhoid fever occurred in Thailand in the 1970s, which peaked in 1975–1976. In response to this typhoid fever outbreak the government of Thailand initiated an immunization program, which resulted in a dramatic reduction in the number of typhoid cases in Thailand. To better understand the population of S. Typhi circulating in Thailand at this time, as well as the impact of the immunization program on the pathogen population, we sequenced the genomes of 44 S. Typhi obtained from hospitals in Thailand before and after the immunization program. The genome sequences showed that isolates of S. Typhi bacteria isolated from post-immunization era typhoid cases were likely imported from neighbouring countries, rather than strains that have persisted in Thailand throughout the immunization period. Our work provides the first historical insights into S. Typhi in Thailand during the 1970s, and provides a model for the impact of immunization on S. Typhi populations.
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Affiliation(s)
- Zoe A. Dyson
- Centre for Systems Genomics, University of Melbourne, Parkville, Victoria, Australia
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Victoria, Australia
- * E-mail: (KEH); (ZAD)
| | - Duy Pham Thanh
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
| | - Ladaporn Bodhidatta
- Department of Enteric Diseases, Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand
| | - Carl Jeffries Mason
- Department of Enteric Diseases, Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand
| | - Apichai Srijan
- Department of Enteric Diseases, Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand
| | - Maia A. Rabaa
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
- Centre for Tropical Medicine and Global Health, Oxford University, Oxford, United Kingdom
| | - Phat Voong Vinh
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
| | - Tuyen Ha Thanh
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
| | - Guy E. Thwaites
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
- Centre for Tropical Medicine and Global Health, Oxford University, Oxford, United Kingdom
| | - Stephen Baker
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
- Centre for Tropical Medicine and Global Health, Oxford University, Oxford, United Kingdom
- The London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Kathryn E. Holt
- Centre for Systems Genomics, University of Melbourne, Parkville, Victoria, Australia
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Victoria, Australia
- * E-mail: (KEH); (ZAD)
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16
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Chung The H, Rabaa MA, Pham Thanh D, De Lappe N, Cormican M, Valcanis M, Howden BP, Wangchuk S, Bodhidatta L, Mason CJ, Nguyen Thi Nguyen T, Vu Thuy D, Thompson CN, Phu Huong Lan N, Voong Vinh P, Ha Thanh T, Turner P, Sar P, Thwaites G, Thomson NR, Holt KE, Baker S. South Asia as a Reservoir for the Global Spread of Ciprofloxacin-Resistant Shigella sonnei: A Cross-Sectional Study. PLoS Med 2016; 13:e1002055. [PMID: 27483136 PMCID: PMC4970813 DOI: 10.1371/journal.pmed.1002055] [Citation(s) in RCA: 67] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/13/2015] [Accepted: 05/18/2016] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Antimicrobial resistance is a major issue in the Shigellae, particularly as a specific multidrug-resistant (MDR) lineage of Shigella sonnei (lineage III) is becoming globally dominant. Ciprofloxacin is a recommended treatment for Shigella infections. However, ciprofloxacin-resistant S. sonnei are being increasingly isolated in Asia and sporadically reported on other continents. We hypothesized that Asia is a primary hub for the recent international spread of ciprofloxacin-resistant S. sonnei. METHODS AND FINDINGS We performed whole-genome sequencing on a collection of 60 contemporaneous ciprofloxacin-resistant S. sonnei isolated in four countries within Asia (Vietnam, n = 11; Bhutan, n = 12; Thailand, n = 1; Cambodia, n = 1) and two outside of Asia (Australia, n = 19; Ireland, n = 16). We reconstructed the recent evolutionary history of these organisms and combined these data with their geographical location of isolation. Placing these sequences into a global phylogeny, we found that all ciprofloxacin-resistant S. sonnei formed a single clade within a Central Asian expansion of lineage III. Furthermore, our data show that resistance to ciprofloxacin within S. sonnei may be globally attributed to a single clonal emergence event, encompassing sequential gyrA-S83L, parC-S80I, and gyrA-D87G mutations. Geographical data predict that South Asia is the likely primary source of these organisms, which are being regularly exported across Asia and intercontinentally into Australia, the United States and Europe. Our analysis was limited by the number of S. sonnei sequences available from diverse geographical areas and time periods, and we cannot discount the potential existence of other unsampled reservoir populations of antimicrobial-resistant S. sonnei. CONCLUSIONS This study suggests that a single clone, which is widespread in South Asia, is likely driving the current intercontinental surge of ciprofloxacin-resistant S. sonnei and is capable of establishing endemic transmission in new locations. Despite being limited in geographical scope, our work has major implications for understanding the international transfer of antimicrobial-resistant pathogens, with S. sonnei acting as a tractable model for studying how antimicrobial-resistant Gram-negative bacteria spread globally.
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Affiliation(s)
- Hao Chung The
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
| | - Maia A. Rabaa
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
- Centre for Tropical Medicine and Global Health, Oxford University, Oxford, United Kingdom
| | - Duy Pham Thanh
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
| | - Niall De Lappe
- National Salmonella, Shigella, and Listeria monocytogenes Reference Laboratory, University Hospital Galway, Galway, Ireland
| | - Martin Cormican
- School of Medicine, National University of Ireland Galway, Galway, Ireland
| | - Mary Valcanis
- Microbiological Diagnostic Unit Public Health Laboratory, Department of Microbiology and Immunology, Peter Doherty Institute for Infection and Immunity, The University of Melbourne, Melbourne, Australia
| | - Benjamin P. Howden
- Microbiological Diagnostic Unit Public Health Laboratory, Department of Microbiology and Immunology, Peter Doherty Institute for Infection and Immunity, The University of Melbourne, Melbourne, Australia
| | - Sonam Wangchuk
- Public Health Laboratory, Department of Public Health, Ministry of Health, Royal Government of Bhutan, Thimphu, Bhutan
| | - Ladaporn Bodhidatta
- Department of Enteric Diseases, Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand
| | - Carl J. Mason
- Department of Enteric Diseases, Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand
| | - To Nguyen Thi Nguyen
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
| | - Duong Vu Thuy
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
| | - Corinne N. Thompson
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
- Centre for Tropical Medicine and Global Health, Oxford University, Oxford, United Kingdom
| | - Nguyen Phu Huong Lan
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
- The Hospital for Tropical Diseases, Ho Chi Minh City, Vietnam
| | - Phat Voong Vinh
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
| | - Tuyen Ha Thanh
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
| | - Paul Turner
- Centre for Tropical Medicine and Global Health, Oxford University, Oxford, United Kingdom
- Cambodia-Oxford Medical Research Unit, Angkor Hospital for Children, Siem Reap, Cambodia
| | - Poda Sar
- Cambodia-Oxford Medical Research Unit, Angkor Hospital for Children, Siem Reap, Cambodia
| | - Guy Thwaites
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
- Centre for Tropical Medicine and Global Health, Oxford University, Oxford, United Kingdom
| | - Nicholas R. Thomson
- The London School of Hygiene and Tropical Medicine, London, United Kingdom
- The Wellcome Trust Sanger Institute, Hinxton, Cambridgeshire, United Kingdom
| | - Kathryn E. Holt
- Centre for Systems Genomics, The University of Melbourne, Melbourne, Australia
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Melbourne, Australia
| | - Stephen Baker
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
- Centre for Tropical Medicine and Global Health, Oxford University, Oxford, United Kingdom
- The Wellcome Trust Sanger Institute, Hinxton, Cambridgeshire, United Kingdom
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17
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Pham Thanh D, Karkey A, Dongol S, Ho Thi N, Thompson CN, Rabaa MA, Arjyal A, Holt KE, Wong V, Tran Vu Thieu N, Voong Vinh P, Ha Thanh T, Pradhan A, Shrestha SK, Gajurel D, Pickard D, Parry CM, Dougan G, Wolbers M, Dolecek C, Thwaites GE, Basnyat B, Baker S. A novel ciprofloxacin-resistant subclade of H58 Salmonella Typhi is associated with fluoroquinolone treatment failure. eLife 2016; 5:e14003. [PMID: 26974227 PMCID: PMC4805543 DOI: 10.7554/elife.14003] [Citation(s) in RCA: 88] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Accepted: 02/19/2016] [Indexed: 01/22/2023] Open
Abstract
The interplay between bacterial antimicrobial susceptibility, phylogenetics and patient outcome is poorly understood. During a typhoid clinical treatment trial in Nepal, we observed several treatment failures and isolated highly fluoroquinolone-resistant Salmonella Typhi (S. Typhi). Seventy-eight S. Typhi isolates were genome sequenced and clinical observations, treatment failures and fever clearance times (FCTs) were stratified by lineage. Most fluoroquinolone-resistant S. Typhi belonged to a specific H58 subclade. Treatment failure with S. Typhi-H58 was significantly less frequent with ceftriaxone (3/31; 9.7%) than gatifloxacin (15/34; 44.1%)(Hazard Ratio 0.19, p=0.002). Further, for gatifloxacin-treated patients, those infected with fluoroquinolone-resistant organisms had significantly higher median FCTs (8.2 days) than those infected with susceptible (2.96) or intermediately resistant organisms (4.01)(p<0.001). H58 is the dominant S. Typhi clade internationally, but there are no data regarding disease outcome with this organism. We report an emergent new subclade of S. Typhi-H58 that is associated with fluoroquinolone treatment failure. Clinical trial registration: ISRCTN63006567. DOI:http://dx.doi.org/10.7554/eLife.14003.001 People who ingest a type of bacteria called Salmonella Typhi can develop the symptoms of typhoid fever. This disease is common in low-income settings in Asia and Africa, and causes a high rate of death in people who are not treated with antimicrobial drugs. During a study in Nepal, Thanh et al. tried to evaluate which of two antimicrobials was better for treating typhoid fever. One of the drugs – called gatifloxacin – did not work in some of the patients. To understand why this treatment failed, Thanh et al. decoded the entire DNA sequences of all the Salmonella Typhi bacteria isolated during the study. Comparing this genetic data to the clinical data of the patients identified a new variant of Salmonella Typhi. These bacteria have a specific combination of genetic mutations that render them resistant to the family of drugs that gatifloxacin belongs to – the fluoroquinolones. Patients infected with the variant bacteria and treated with gatifloxacin were highly likely to completely fail treatment and have longer-lasting fevers. On further investigation Thanh et al. found these organisms were likely recently introduced into Nepal from India. Fluoroquinolones are amongst the most effective and common antimicrobials used to treat typhoid fever and other bacterial infections. However, the presence of bacteria that are resistant to these compounds in South Asia means that they should no longer be the first choice of drug to treat typhoid fever in this location. DOI:http://dx.doi.org/10.7554/eLife.14003.002
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Affiliation(s)
- Duy Pham Thanh
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
| | - Abhilasha Karkey
- Oxford University Clinical Research Unit, Patan Academy of Health Sciences, Kathmandu, Nepal
| | - Sabina Dongol
- Oxford University Clinical Research Unit, Patan Academy of Health Sciences, Kathmandu, Nepal
| | - Nhan Ho Thi
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
| | - Corinne N Thompson
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam.,Centre for Tropical Medicine and Global Health, Oxford University, Oxford, United Kingdom.,The London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Maia A Rabaa
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam.,Centre for Tropical Medicine and Global Health, Oxford University, Oxford, United Kingdom
| | - Amit Arjyal
- Oxford University Clinical Research Unit, Patan Academy of Health Sciences, Kathmandu, Nepal
| | - Kathryn E Holt
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, Australia
| | - Vanessa Wong
- The Wellcome Trust Sanger Institute, Cambridge, United Kingdom
| | - Nga Tran Vu Thieu
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
| | - Phat Voong Vinh
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
| | - Tuyen Ha Thanh
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
| | | | | | | | - Derek Pickard
- The Wellcome Trust Sanger Institute, Cambridge, United Kingdom
| | - Christopher M Parry
- The London School of Hygiene and Tropical Medicine, London, United Kingdom.,School of Tropical Medicine and Global Health, Department of Clinical Research, Nagasaki University, Nagasaki, Japan
| | - Gordon Dougan
- The Wellcome Trust Sanger Institute, Cambridge, United Kingdom
| | - Marcel Wolbers
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam.,Centre for Tropical Medicine and Global Health, Oxford University, Oxford, United Kingdom
| | - Christiane Dolecek
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam.,Centre for Tropical Medicine and Global Health, Oxford University, Oxford, United Kingdom.,Department of Zoology, University of Oxford, Oxford, United Kingdom
| | - Guy E Thwaites
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam.,Centre for Tropical Medicine and Global Health, Oxford University, Oxford, United Kingdom
| | - Buddha Basnyat
- Oxford University Clinical Research Unit, Patan Academy of Health Sciences, Kathmandu, Nepal
| | - Stephen Baker
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam.,Centre for Tropical Medicine and Global Health, Oxford University, Oxford, United Kingdom.,The London School of Hygiene and Tropical Medicine, London, United Kingdom
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18
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Karkey A, Jombart T, Walker AW, Thompson CN, Torres A, Dongol S, Tran Vu Thieu N, Pham Thanh D, Tran Thi Ngoc D, Voong Vinh P, Singer AC, Parkhill J, Thwaites G, Basnyat B, Ferguson N, Baker S. The Ecological Dynamics of Fecal Contamination and Salmonella Typhi and Salmonella Paratyphi A in Municipal Kathmandu Drinking Water. PLoS Negl Trop Dis 2016; 10:e0004346. [PMID: 26735696 PMCID: PMC4703202 DOI: 10.1371/journal.pntd.0004346] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2015] [Accepted: 12/09/2015] [Indexed: 11/20/2022] Open
Abstract
One of the UN sustainable development goals is to achieve universal access to safe and affordable drinking water by 2030. It is locations like Kathmandu, Nepal, a densely populated city in South Asia with endemic typhoid fever, where this goal is most pertinent. Aiming to understand the public health implications of water quality in Kathmandu we subjected weekly water samples from 10 sources for one year to a range of chemical and bacteriological analyses. We additionally aimed to detect the etiological agents of typhoid fever and longitudinally assess microbial diversity by 16S rRNA gene surveying. We found that the majority of water sources exhibited chemical and bacterial contamination exceeding WHO guidelines. Further analysis of the chemical and bacterial data indicated site-specific pollution, symptomatic of highly localized fecal contamination. Rainfall was found to be a key driver of this fecal contamination, correlating with nitrates and evidence of S. Typhi and S. Paratyphi A, for which DNA was detectable in 333 (77%) and 303 (70%) of 432 water samples, respectively. 16S rRNA gene surveying outlined a spectrum of fecal bacteria in the contaminated water, forming complex communities again displaying location-specific temporal signatures. Our data signify that the municipal water in Kathmandu is a predominant vehicle for the transmission of S. Typhi and S. Paratyphi A. This study represents the first extensive spatiotemporal investigation of water pollution in an endemic typhoid fever setting and implicates highly localized human waste as the major contributor to poor water quality in the Kathmandu Valley. Aiming to understand the ecology of municipal drinking water and measure the potential exposure to pathogens that cause typhoid fever (Salmonella Typhi and Salmonella Paratyphi A) in Kathmandu, Nepal, we collected water samples from 10 water sources weekly for one year and subjected them to comprehensive chemical, bacteriological and molecular analyses. We found that Kathmandu drinking water exhibits longitudinal fecal contamination in excess of WHO guidelines. The chemical composition of water indicated site-specific pollution profiles, which were likely driven by localized contamination with human fecal material. We additionally found that Salmonella Typhi and Salmonella Paratyphi A could be detected throughout the year in every water sampling location, but specifically peaked after the monsoons. A microbiota analysis (a method for studying bacterial diversity in biological samples) revealed the water to be contaminated by complex populations of fecal bacteria, which again exhibited a unique profile by both location and time. This study shows that Salmonella Typhi and Salmonella Paratyphi A can be longitudinally detected in drinking water in Kathmandu and represents the first major investigation of the spatiotemporal dynamics of drinking water pollution in an endemic typhoid setting.
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Affiliation(s)
- Abhilasha Karkey
- Oxford University Clinical Research Unit, Patan Academy of Health Sciences, Kathmandu, Nepal
| | - Thibaut Jombart
- MRC Centre for Outbreak Analysis and Modelling, Department of Infectious Disease Epidemiology, School of Public Health, Imperial College London, London, United Kingdom
| | - Alan W. Walker
- The Wellcome Trust Sanger Institute, Hinxton, Cambridgeshire, United Kingdom
- Microbiology Group, The Rowett Institute of Nutrition and Health, University of Aberdeen, Aberdeen, United Kingdom
| | - Corinne N. Thompson
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
- Centre for Tropical Medicine, Oxford University, Oxford, United Kingdom
| | - Andres Torres
- Grupo de Investigación Ciencia e Ingeniería del Agua y el Ambiente, Facultad de Ingeniería, Pontificia Universidad Javeriana, Bogotá, Colombia
| | - Sabina Dongol
- Oxford University Clinical Research Unit, Patan Academy of Health Sciences, Kathmandu, Nepal
| | - Nga Tran Vu Thieu
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
| | - Duy Pham Thanh
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
| | - Dung Tran Thi Ngoc
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
| | - Phat Voong Vinh
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
| | - Andrew C. Singer
- NERC Centre for Ecology and Hydrology, Wallingford, Oxfordshire, United Kingdom
| | - Julian Parkhill
- The Wellcome Trust Sanger Institute, Hinxton, Cambridgeshire, United Kingdom
| | - Guy Thwaites
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
- Centre for Tropical Medicine, Oxford University, Oxford, United Kingdom
| | - Buddha Basnyat
- Oxford University Clinical Research Unit, Patan Academy of Health Sciences, Kathmandu, Nepal
| | - Neil Ferguson
- MRC Centre for Outbreak Analysis and Modelling, Department of Infectious Disease Epidemiology, School of Public Health, Imperial College London, London, United Kingdom
| | - Stephen Baker
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
- Centre for Tropical Medicine, Oxford University, Oxford, United Kingdom
- The London School of Hygiene and Tropical Medicine, London, United Kingdom
- * E-mail:
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19
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Chung The H, Rabaa MA, Thanh DP, Ruekit S, Wangchuk S, Dorji T, Tshering KP, Nguyen TNT, Vinh PV, Thanh TH, Minh CNN, Turner P, Sar P, Thwaites G, Holt KE, Thomson NR, Bodhidatta L, Jeffries Mason C, Baker S. Introduction and establishment of fluoroquinolone-resistant Shigella sonnei into Bhutan. Microb Genom 2015; 1:e000042. [PMID: 28348825 PMCID: PMC5320628 DOI: 10.1099/mgen.0.000042] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2015] [Accepted: 11/19/2015] [Indexed: 11/26/2022] Open
Abstract
Shigella sonnei is a major contributor to the global burden of diarrhoeal disease, generally associated with dysenteric diarrhoea in developed countries but also emerging in developing countries. The reason for the recent success of S. sonnei is unknown, but is likely catalysed by its ability to acquire resistance against multiple antimicrobials. Between 2011 and 2013, S. sonnei exhibiting resistance to fluoroquinolones, the first-line treatment recommended for shigellosis, emerged in Bhutan. Aiming to reconstruct the introduction and establishment of fluoroquinolone-resistant S. sonnei populations in Bhutan, we performed whole-genome sequencing on 71 S. sonnei samples isolated in Bhutan between 2011 and 2013.We found that these strains represented an expansion of a clade within the previously described lineage III, found specifically in Central Asia. Temporal phylogenetic reconstruction demonstrated that all of the sequenced Bhutanese S. sonnei diverged from a single ancestor that was introduced into Bhutan around 2006. Our data additionally predicted that fluoroquinolone resistance, conferred by mutations in gyrA and parC, arose prior to the introduction of the founder strain into Bhutan. Once established in Bhutan, these S. sonnei had access to a broad gene pool, as indicated by the acquisition of extended-spectrum β-lactamase-encoding plasmids and genes encoding type IV pili. The data presented here outline a model for the introduction and maintenance of fluoroquinolone-resistant S. sonnei in a new setting. Given the current circulation of fluoroquinolone-resistant S. sonnei in Asia, we speculate that this pattern of introduction is being recapitulated across the region and beyond.
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Affiliation(s)
- Hao Chung The
- The Hospital for Tropical Diseases, OUCRU, Ho Chi Minh City, Vietnam
| | - Maia A Rabaa
- The Hospital for Tropical Diseases, OUCRU, Ho Chi Minh City, Vietnam.,Centre for Tropical Medicine, Oxford University, Oxford, UK
| | - Duy Pham Thanh
- The Hospital for Tropical Diseases, OUCRU, Ho Chi Minh City, Vietnam
| | | | - Sonam Wangchuk
- Public Health Laboratory, Department of Public Health, Ministry of Health, Royal Government of Bhutan, Thimphu, Bhutan
| | - Tshering Dorji
- Public Health Laboratory, Department of Public Health, Ministry of Health, Royal Government of Bhutan, Thimphu, Bhutan
| | - Kinzang Pem Tshering
- Department of Pediatrics, Jigme Dorji Wangchuk Referral Hospital, Kawa Jangsa, Thimphu, Bhutan
| | | | - Phat Voong Vinh
- The Hospital for Tropical Diseases, OUCRU, Ho Chi Minh City, Vietnam
| | - Tuyen Ha Thanh
- The Hospital for Tropical Diseases, OUCRU, Ho Chi Minh City, Vietnam
| | | | - Paul Turner
- Centre for Tropical Medicine, Oxford University, Oxford, UK.,Cambodia-Oxford Medical Research Unit, Angkor Hospital for Children, Siem Reap, Cambodia
| | - Poda Sar
- Cambodia-Oxford Medical Research Unit, Angkor Hospital for Children, Siem Reap, Cambodia
| | - Guy Thwaites
- The Hospital for Tropical Diseases, OUCRU, Ho Chi Minh City, Vietnam.,Centre for Tropical Medicine, Oxford University, Oxford, UK
| | - Kathryn E Holt
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Victoria 3010, Australia
| | - Nicholas R Thomson
- The Wellcome Trust Sanger Institute, Hinxton, Cambridgeshire, UK.,The London School of Hygiene and Tropical Medicine, London, UK
| | | | | | - Stephen Baker
- The Hospital for Tropical Diseases, OUCRU, Ho Chi Minh City, Vietnam.,Centre for Tropical Medicine, Oxford University, Oxford, UK.,The London School of Hygiene and Tropical Medicine, London, UK
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20
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Thompson CN, Thieu NTV, Vinh PV, Duc AN, Wolbers M, Vinh H, Campbell JI, Ngoc DTT, Hoang NVM, Thanh TH, The HC, Nguyen TNT, Lan NPH, Parry CM, Chau NVV, Thwaites G, Thanh DP, Baker S. Clinical implications of reduced susceptibility to fluoroquinolones in paediatric Shigella sonnei and Shigella flexneri infections. J Antimicrob Chemother 2015; 71:807-15. [PMID: 26679253 PMCID: PMC4743702 DOI: 10.1093/jac/dkv400] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2015] [Accepted: 10/26/2015] [Indexed: 11/25/2022] Open
Abstract
Objectives We aimed to quantify the impact of fluoroquinolone resistance on the clinical outcome of paediatric shigellosis patients treated with fluoroquinolones in southern Vietnam. Such information is important to inform therapeutic management for infections caused by this increasingly drug-resistant pathogen, responsible for high morbidity and mortality in young children globally. Methods Clinical information and bacterial isolates were derived from a randomized controlled trial comparing gatifloxacin with ciprofloxacin for the treatment of paediatric shigellosis. Time–kill experiments were performed to evaluate the impact of MIC on the in vitro growth of Shigella and Cox regression modelling was used to compare clinical outcome between treatments and Shigella species. Results Shigella flexneri patients treated with gatifloxacin had significantly worse outcomes than those treated with ciprofloxacin. However, the MICs of fluoroquinolones were not significantly associated with poorer outcome. The presence of S83L and A87T mutations in the gyrA gene significantly increased MICs of fluoroquinolones. Finally, elevated MICs and the presence of the qnrS gene allowed Shigella to replicate efficiently in vitro in high concentrations of ciprofloxacin. Conclusions We found that below the CLSI breakpoint, there was no association between MIC and clinical outcome in paediatric shigellosis infections. However, S. flexneri patients had worse clinical outcomes when treated with gatifloxacin in this study regardless of MIC. Additionally, Shigella harbouring the qnrS gene are able to replicate efficiently in high concentrations of ciprofloxacin and we hypothesize that such strains possess a competitive advantage against fluoroquinolone-susceptible strains due to enhanced shedding and transmission.
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Affiliation(s)
- Corinne N Thompson
- Oxford University Clinical Research Unit, Wellcome Trust Major Overseas Programme, The Hospital for Tropical Diseases, Ho Chi Minh City, Vietnam Centre for Tropical Medicine, Oxford University, Oxford, UK The London School of Hygiene and Tropical Medicine, London, UK
| | - Nga Tran Vu Thieu
- Oxford University Clinical Research Unit, Wellcome Trust Major Overseas Programme, The Hospital for Tropical Diseases, Ho Chi Minh City, Vietnam
| | - Phat Voong Vinh
- Oxford University Clinical Research Unit, Wellcome Trust Major Overseas Programme, The Hospital for Tropical Diseases, Ho Chi Minh City, Vietnam
| | - Anh Nguyen Duc
- Oxford University Clinical Research Unit, Wellcome Trust Major Overseas Programme, The Hospital for Tropical Diseases, Ho Chi Minh City, Vietnam
| | - Marcel Wolbers
- Oxford University Clinical Research Unit, Wellcome Trust Major Overseas Programme, The Hospital for Tropical Diseases, Ho Chi Minh City, Vietnam Centre for Tropical Medicine, Oxford University, Oxford, UK
| | - Ha Vinh
- The Hospital for Tropical Diseases, Ho Chi Minh City, Vietnam
| | - James I Campbell
- Oxford University Clinical Research Unit, Wellcome Trust Major Overseas Programme, The Hospital for Tropical Diseases, Ho Chi Minh City, Vietnam Centre for Tropical Medicine, Oxford University, Oxford, UK
| | - Dung Tran Thi Ngoc
- Oxford University Clinical Research Unit, Wellcome Trust Major Overseas Programme, The Hospital for Tropical Diseases, Ho Chi Minh City, Vietnam
| | - Nguyen Van Minh Hoang
- Oxford University Clinical Research Unit, Wellcome Trust Major Overseas Programme, The Hospital for Tropical Diseases, Ho Chi Minh City, Vietnam
| | - Tuyen Ha Thanh
- Oxford University Clinical Research Unit, Wellcome Trust Major Overseas Programme, The Hospital for Tropical Diseases, Ho Chi Minh City, Vietnam
| | - Hao Chung The
- Oxford University Clinical Research Unit, Wellcome Trust Major Overseas Programme, The Hospital for Tropical Diseases, Ho Chi Minh City, Vietnam
| | - To Nguyen Thi Nguyen
- Oxford University Clinical Research Unit, Wellcome Trust Major Overseas Programme, The Hospital for Tropical Diseases, Ho Chi Minh City, Vietnam
| | - Nguyen Phu Huong Lan
- Oxford University Clinical Research Unit, Wellcome Trust Major Overseas Programme, The Hospital for Tropical Diseases, Ho Chi Minh City, Vietnam The Hospital for Tropical Diseases, Ho Chi Minh City, Vietnam
| | - Christopher M Parry
- The London School of Hygiene and Tropical Medicine, London, UK School of Tropical Medicine and Global Health, Nagasaki University, Nagasaki, Japan
| | | | - Guy Thwaites
- Oxford University Clinical Research Unit, Wellcome Trust Major Overseas Programme, The Hospital for Tropical Diseases, Ho Chi Minh City, Vietnam Centre for Tropical Medicine, Oxford University, Oxford, UK
| | - Duy Pham Thanh
- Oxford University Clinical Research Unit, Wellcome Trust Major Overseas Programme, The Hospital for Tropical Diseases, Ho Chi Minh City, Vietnam
| | - Stephen Baker
- Oxford University Clinical Research Unit, Wellcome Trust Major Overseas Programme, The Hospital for Tropical Diseases, Ho Chi Minh City, Vietnam Centre for Tropical Medicine, Oxford University, Oxford, UK The London School of Hygiene and Tropical Medicine, London, UK
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21
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Dunstan SJ, Hue NT, Han B, Li Z, Tram TTB, Sim KS, Parry CM, Chinh NT, Vinh H, Lan NPH, Thieu NTV, Vinh PV, Koirala S, Dongol S, Arjyal A, Karkey A, Shilpakar O, Dolecek C, Foo JN, Phuong LT, Lanh MN, Do T, Aung T, Hon DN, Teo YY, Hibberd ML, Anders KL, Okada Y, Raychaudhuri S, Simmons CP, Baker S, de Bakker PIW, Basnyat B, Hien TT, Farrar JJ, Khor CC. Variation at HLA-DRB1 is associated with resistance to enteric fever. Nat Genet 2014; 46:1333-6. [PMID: 25383971 PMCID: PMC5099079 DOI: 10.1038/ng.3143] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2014] [Accepted: 10/15/2014] [Indexed: 12/18/2022]
Abstract
Enteric fever affects more than 25 million people annually and results from systemic infection with Salmonella enterica serovar Typhi or Paratyphi pathovars A, B or C(1). We conducted a genome-wide association study of 432 individuals with blood culture-confirmed enteric fever and 2,011 controls from Vietnam. We observed strong association at rs7765379 (odds ratio (OR) for the minor allele = 0.18, P = 4.5 × 10(-10)), a marker mapping to the HLA class II region, in proximity to HLA-DQB1 and HLA-DRB1. We replicated this association in 595 enteric fever cases and 386 controls from Nepal and also in a second independent collection of 151 cases and 668 controls from Vietnam. Imputation-based fine-mapping across the extended MHC region showed that the classical HLA-DRB1*04:05 allele (OR = 0.14, P = 2.60 × 10(-11)) could entirely explain the association at rs7765379, thus implicating HLA-DRB1 as a major contributor to resistance against enteric fever, presumably through antigen presentation.
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Affiliation(s)
- Sarah J Dunstan
- 1] Oxford University Clinical Research Unit, Hospital for Tropical Diseases, Ho Chi Minh City, Vietnam. [2] Centre for Tropical Medicine, Nuffield Department of Clinical Medicine, Oxford University, Oxford, UK. [3] Nossal Institute of Global Health, Melbourne School of Population and Global Health, The University of Melbourne, Melbourne, Victoria, Australia
| | - Nguyen Thi Hue
- 1] Oxford University Clinical Research Unit, Hospital for Tropical Diseases, Ho Chi Minh City, Vietnam. [2] Faculty of Biology, University of Science, Vietnam National University, Ho Chi Minh City, Vietnam
| | - Buhm Han
- 1] Asan Institute for Life Sciences, University of Ulsan College of Medicine, Asan Medical Center, Seoul, Republic of Korea. [2] Department of Medicine, Division of Genetics, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA. [3] Program in Medical and Population Genetics, Broad Institute, Cambridge, Massachusetts, USA. [4] Partners Center for Personalized Genetic Medicine, Boston, Massachusetts, USA
| | - Zheng Li
- Genome Institute of Singapore, Singapore
| | - Trinh Thi Bich Tram
- Oxford University Clinical Research Unit, Hospital for Tropical Diseases, Ho Chi Minh City, Vietnam
| | | | - Christopher M Parry
- 1] Oxford University Clinical Research Unit, Hospital for Tropical Diseases, Ho Chi Minh City, Vietnam. [2] Liverpool School of Tropical Medicine, Liverpool, UK
| | | | - Ha Vinh
- Hospital for Tropical Diseases, Ho Chi Minh City, Vietnam
| | | | - Nga Tran Vu Thieu
- Oxford University Clinical Research Unit, Hospital for Tropical Diseases, Ho Chi Minh City, Vietnam
| | - Phat Voong Vinh
- Oxford University Clinical Research Unit, Hospital for Tropical Diseases, Ho Chi Minh City, Vietnam
| | - Samir Koirala
- Oxford University Clinical Research Unit-Nepal, Patan Academy of Health Sciences, Patan Hospital, Patan, Nepal
| | - Sabina Dongol
- Oxford University Clinical Research Unit-Nepal, Patan Academy of Health Sciences, Patan Hospital, Patan, Nepal
| | - Amit Arjyal
- Oxford University Clinical Research Unit-Nepal, Patan Academy of Health Sciences, Patan Hospital, Patan, Nepal
| | - Abhilasha Karkey
- Oxford University Clinical Research Unit-Nepal, Patan Academy of Health Sciences, Patan Hospital, Patan, Nepal
| | - Olita Shilpakar
- Oxford University Clinical Research Unit-Nepal, Patan Academy of Health Sciences, Patan Hospital, Patan, Nepal
| | - Christiane Dolecek
- 1] Oxford University Clinical Research Unit, Hospital for Tropical Diseases, Ho Chi Minh City, Vietnam. [2] Centre for Tropical Medicine, Nuffield Department of Clinical Medicine, Oxford University, Oxford, UK
| | | | | | | | - Tan Do
- Vietnam National Institute of Ophthalmology, Hanoi, Vietnam
| | - Tin Aung
- Singapore Eye Research Institute, Singapore
| | - Do Nu Hon
- Vietnam National Institute of Ophthalmology, Hanoi, Vietnam
| | - Yik Ying Teo
- 1] Department of Statistics and Applied Probability, National University of Singapore, Singapore. [2] Saw Swee Hock School of Public Health, National University of Singapore, Singapore
| | - Martin L Hibberd
- 1] Genome Institute of Singapore, Singapore. [2] London School of Tropical Medicine and Hygiene, London, UK
| | - Katherine L Anders
- 1] Oxford University Clinical Research Unit, Hospital for Tropical Diseases, Ho Chi Minh City, Vietnam. [2] Centre for Tropical Medicine, Nuffield Department of Clinical Medicine, Oxford University, Oxford, UK
| | - Yukinori Okada
- 1] Department of Human Genetics and Disease Diversity, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan. [2] Laboratory for Statistical Analysis, RIKEN Center for Integrative Medical Sciences, Yokohama, Japan
| | - Soumya Raychaudhuri
- 1] Department of Medicine, Division of Genetics, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA. [2] Program in Medical and Population Genetics, Broad Institute, Cambridge, Massachusetts, USA. [3] Partners Center for Personalized Genetic Medicine, Boston, Massachusetts, USA. [4] Department of Medicine, Division of Rheumatology, Immunology and Allergy, Brigham and Women's Hospital, Boston, Massachusetts, USA. [5] Faculty of Medical and Human Sciences, University of Manchester, Manchester, UK
| | - Cameron P Simmons
- 1] Oxford University Clinical Research Unit, Hospital for Tropical Diseases, Ho Chi Minh City, Vietnam. [2] Centre for Tropical Medicine, Nuffield Department of Clinical Medicine, Oxford University, Oxford, UK. [3] Department of Microbiology and Immunology, The University of Melbourne, Melbourne, Victoria, Australia
| | - Stephen Baker
- 1] Oxford University Clinical Research Unit, Hospital for Tropical Diseases, Ho Chi Minh City, Vietnam. [2] Centre for Tropical Medicine, Nuffield Department of Clinical Medicine, Oxford University, Oxford, UK. [3] London School of Tropical Medicine and Hygiene, London, UK
| | - Paul I W de Bakker
- 1] Department of Medical Genetics, Center for Molecular Medicine, University Medical Center Utrecht, Utrecht, the Netherlands. [2] Department of Epidemiology, Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, Utrecht, the Netherlands
| | - Buddha Basnyat
- Oxford University Clinical Research Unit-Nepal, Patan Academy of Health Sciences, Patan Hospital, Patan, Nepal
| | - Tran Tinh Hien
- Oxford University Clinical Research Unit, Hospital for Tropical Diseases, Ho Chi Minh City, Vietnam
| | - Jeremy J Farrar
- 1] Oxford University Clinical Research Unit, Hospital for Tropical Diseases, Ho Chi Minh City, Vietnam. [2] Centre for Tropical Medicine, Nuffield Department of Clinical Medicine, Oxford University, Oxford, UK
| | - Chiea Chuen Khor
- 1] Genome Institute of Singapore, Singapore. [2] Singapore Eye Research Institute, Singapore. [3] Saw Swee Hock School of Public Health, National University of Singapore, Singapore. [4] Department of Paediatrics, Yong Loo Lin School of Medicine, National University of Singapore, Singapore. [5] Department of Ophthalmology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
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22
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Näsström E, Vu Thieu NT, Dongol S, Karkey A, Voong Vinh P, Ha Thanh T, Johansson A, Arjyal A, Thwaites G, Dolecek C, Basnyat B, Baker S, Antti H. Salmonella Typhi and Salmonella Paratyphi A elaborate distinct systemic metabolite signatures during enteric fever. eLife 2014; 3. [PMID: 24902583 PMCID: PMC4077204 DOI: 10.7554/elife.03100] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2014] [Accepted: 05/26/2014] [Indexed: 12/31/2022] Open
Abstract
The host-pathogen interactions induced by Salmonella Typhi and Salmonella Paratyphi A during enteric fever are poorly understood. This knowledge gap, and the human restricted nature of these bacteria, limit our understanding of the disease and impede the development of new diagnostic approaches. To investigate metabolite signals associated with enteric fever we performed two dimensional gas chromatography with time-of-flight mass spectrometry (GCxGC/TOFMS) on plasma from patients with S. Typhi and S. Paratyphi A infections and asymptomatic controls, identifying 695 individual metabolite peaks. Applying supervised pattern recognition, we found highly significant and reproducible metabolite profiles separating S. Typhi cases, S. Paratyphi A cases, and controls, calculating that a combination of six metabolites could accurately define the etiological agent. For the first time we show that reproducible and serovar specific systemic biomarkers can be detected during enteric fever. Our work defines several biologically plausible metabolites that can be used to detect enteric fever, and unlocks the potential of this method in diagnosing other systemic bacterial infections.
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Affiliation(s)
- Elin Näsström
- Department of Chemistry, Computational Life Science Cluster, Umeå University, Umeå, Sweden
| | - Nga Tran Vu Thieu
- Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, The Hospital for Tropical Diseases, Ho Chi Minh City, Vietnam
| | - Sabina Dongol
- Oxford University Clinical Research Unit, Patan Academy of Health Sciences, Kathmandu, Nepal
| | - Abhilasha Karkey
- Oxford University Clinical Research Unit, Patan Academy of Health Sciences, Kathmandu, Nepal
| | - Phat Voong Vinh
- Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, The Hospital for Tropical Diseases, Ho Chi Minh City, Vietnam
| | - Tuyen Ha Thanh
- Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, The Hospital for Tropical Diseases, Ho Chi Minh City, Vietnam
| | - Anders Johansson
- Department of Clinical Microbiology, Umeå University, Umeå, Sweden
| | - Amit Arjyal
- Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, The Hospital for Tropical Diseases, Ho Chi Minh City, Vietnam
| | - Guy Thwaites
- Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, The Hospital for Tropical Diseases, Ho Chi Minh City, Vietnam
| | - Christiane Dolecek
- Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, The Hospital for Tropical Diseases, Ho Chi Minh City, Vietnam
| | - Buddha Basnyat
- Oxford University Clinical Research Unit, Patan Academy of Health Sciences, Kathmandu, Nepal
| | - Stephen Baker
- Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, The Hospital for Tropical Diseases, Ho Chi Minh City, Vietnam
| | - Henrik Antti
- Department of Chemistry, Computational Life Science Cluster, Umeå University, Umeå, Sweden
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23
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Moore CE, Pan-Ngum W, Wijedoru LPM, Sona S, Nga TVT, Duy PT, Vinh PV, Chheng K, Kumar V, Emary K, Carter M, White L, Baker S, Day NPJ, Parry CM. Evaluation of the diagnostic accuracy of a typhoid IgM flow assay for the diagnosis of typhoid fever in Cambodian children using a Bayesian latent class model assuming an imperfect gold standard. Am J Trop Med Hyg 2013; 90:114-120. [PMID: 24218407 PMCID: PMC3886406 DOI: 10.4269/ajtmh.13-0384] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Rapid diagnostic tests are needed for typhoid fever (TF) diagnosis in febrile children in endemic areas. Five hundred children admitted to the hospital in Cambodia between 2009 and 2010 with documented fever (≥ 38°C) were investigated using blood cultures (BCs), Salmonella Typhi/Paratyphi A real-time polymerase chain reactions (PCRs), and a Typhoid immunoglobulin M flow assay (IgMFA). Test performance was determined by conventional methods and Bayesian latent class modeling. There were 32 cases of TF (10 BC- and PCR-positive cases, 14 BC-positive and PCR-negative cases, and 8 BC-negative and PCR-positive cases). IgMFA sensitivity was 59.4% (95% confidence interval = 41–76), and specificity was 97.8% (95% confidence interval = 96–99). The model estimate sensitivity for BC was 81.0% (95% credible interval = 54–99). The model estimate sensitivity for PCR was 37.8% (95% credible interval = 26–55), with a specificity of 98.2% (95% credible interval = 97–99). The model estimate sensitivity for IgMFA (≥ 2+) was 77.9% (95% credible interval = 58–90), with a specificity of 97.5% (95% credible interval = 95–100). The model estimates of IgMFA sensitivity and specificity were comparable with BCs and better than estimates using conventional analysis.
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Affiliation(s)
- Catrin E. Moore
- *Address correspondence to Catrin E. Moore, Pneumococcal Vaccine Group, Microbiology, Level 7, John Radcliffe Hospital, Headington, Oxford, United Kingdom. E-mail:
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Karkey A, Thompson CN, Tran Vu Thieu N, Dongol S, Le Thi Phuong T, Voong Vinh P, Arjyal A, Martin LB, Rondini S, Farrar JJ, Dolecek C, Basnyat B, Baker S. Differential epidemiology of Salmonella Typhi and Paratyphi A in Kathmandu, Nepal: a matched case control investigation in a highly endemic enteric fever setting. PLoS Negl Trop Dis 2013; 7:e2391. [PMID: 23991240 PMCID: PMC3749961 DOI: 10.1371/journal.pntd.0002391] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2013] [Accepted: 07/17/2013] [Indexed: 01/08/2023] Open
Abstract
Background Enteric fever, a systemic infection caused by the bacteria Salmonella Typhi and Salmonella Paratyphi A, is endemic in Kathmandu, Nepal. Previous work identified proximity to poor quality water sources as a community-level risk for infection. Here, we sought to examine individual-level risk factors related to hygiene and sanitation to improve our understanding of the epidemiology of enteric fever in this setting. Methodology and principal findings A matched case-control analysis was performed through enrollment of 103 blood culture positive enteric fever patients and 294 afebrile community-based age and gender-matched controls. A detailed questionnaire was administered to both cases and controls and the association between enteric fever infection and potential exposures were examined through conditional logistic regression. Several behavioral practices were identified as protective against infection with enteric fever, including water storage and hygienic habits. Additionally, we found that exposures related to poor water and socioeconomic status are more influential in the risk of infection with S. Typhi, whereas food consumption habits and migration play more of a role in risk of S. Paratyphi A infection. Conclusions and significance Our work suggests that S. Typhi and S. Paratyphi A follow different routes of infection in this highly endemic setting and that sustained exposure to both serovars probably leads to the development of passive immunity. In the absence of a polyvalent vaccine against S. Typhi and S. Paratyphi A, we advocate better systems for water treatment and storage, improvements in the quality of street food, and vaccination with currently available S. Typhi vaccines. Enteric fever, caused by ingestion of bacteria Salmonella Typhi or Salmonella Paratyphi A, is common in regions with poor water quality and sanitation. We sought to identify individual-level risks for infection in Kathmandu, Nepal, a region endemic for enteric fever. In this study, we enrolled patients presenting to hospital who were blood-culture positive for enteric fever and a series of community controls matched for age, gender and residential ward. Our findings suggest that while some risks for infection with S. Typhi and S. Paratyphi A overlap, these organisms also have distinctive routes of infection in this setting; poor water and socioeconomic status seemed more influential in infection with S. Typhi, whereas food consumption habits and migratory status were shown to play a larger role in infection with S. Paratyphi A. Additionally, serological evaluation of IgG levels against the Vi (Salmonella Typhi) and the O:2 (Salmonella Paratyphi A) antigens demonstrated high titers against both antigens throughout life, suggesting frequent and constant exposure to these organisms in Kathmandu. As major improvements in sanitation infrastructure are unlikely in this setting, we recommend water treatment and storage-based prevention strategies, as well as street food quality regulation, and the promotion of vaccination with existing typhoid vaccines.
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Affiliation(s)
- Abhilasha Karkey
- Oxford University Clinical Research Unit, Patan Academy of Health Sciences, Kathmandu, Nepal
| | - Corinne N. Thompson
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
- Centre for Tropical Medicine, Oxford University, Oxford, United Kingdom
| | - Nga Tran Vu Thieu
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
| | - Sabina Dongol
- Oxford University Clinical Research Unit, Patan Academy of Health Sciences, Kathmandu, Nepal
| | - Tu Le Thi Phuong
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
| | - Phat Voong Vinh
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
| | - Amit Arjyal
- Oxford University Clinical Research Unit, Patan Academy of Health Sciences, Kathmandu, Nepal
| | | | - Simona Rondini
- Novartis Institute Vaccines for Global Health, Siena, Italy
| | - Jeremy J. Farrar
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
- Centre for Tropical Medicine, Oxford University, Oxford, United Kingdom
| | | | - Buddha Basnyat
- Oxford University Clinical Research Unit, Patan Academy of Health Sciences, Kathmandu, Nepal
| | - Stephen Baker
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
- Centre for Tropical Medicine, Oxford University, Oxford, United Kingdom
- The London School of Hygiene and Tropical Medicine, London, United Kingdom
- * E-mail:
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