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Zhou X, Kang X, Chen J, Song Y, Jia C, Teng L, Tang Y, Jiang Z, Peng X, Tao X, Xu Y, Huang L, Xu X, Xu Y, Zhang T, Yu S, Gong J, Wang S, Liu Y, Zhu G, Kehrenberg C, Weill FX, Barrow P, Li Y, Zhao G, Yue M. Genome degradation promotes Salmonella pathoadaptation by remodeling fimbriae-mediated proinflammatory response. Natl Sci Rev 2023; 10:nwad228. [PMID: 37965675 PMCID: PMC10642762 DOI: 10.1093/nsr/nwad228] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2023] [Revised: 07/07/2023] [Accepted: 08/08/2023] [Indexed: 11/16/2023] Open
Abstract
Understanding changes in pathogen behavior (e.g. increased virulence, a shift in transmission channel) is critical for the public health management of emerging infectious diseases. Genome degradation via gene depletion or inactivation is recognized as a pathoadaptive feature of the pathogen evolving with the host. However, little is known about the exact role of genome degradation in affecting pathogenic behavior, and the underlying molecular detail has yet to be examined. Using large-scale global avian-restricted Salmonella genomes spanning more than a century, we projected the genetic diversity of Salmonella Pullorum (bvSP) by showing increasingly antimicrobial-resistant ST92 prevalent in Chinese flocks. The phylogenomic analysis identified three lineages in bvSP, with an enhancement of virulence in the two recently emerged lineages (L2/L3), as evidenced in chicken and embryo infection assays. Notably, the ancestor L1 lineage resembles the Salmonella serovars with higher metabolic flexibilities and more robust environmental tolerance, indicating stepwise evolutionary trajectories towards avian-restricted lineages. Pan-genome analysis pinpointed fimbrial degradation from a virulent lineage. The later engineered fim-deletion mutant, and all other five fimbrial systems, revealed behavior switching that restricted horizontal fecal-oral transmission but boosted virulence in chicks. By depleting fimbrial appendages, bvSP established persistent replication with less proinflammation in chick macrophages and adopted vertical transovarial transmission, accompanied by ever-increasing intensification in the poultry industry. Together, we uncovered a previously unseen paradigm for remodeling bacterial surface appendages that supplements virulence-enhanced evolution with increased vertical transmission.
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Affiliation(s)
- Xiao Zhou
- Institute of Preventive Veterinary Sciences and Department of Veterinary Medicine, Zhejiang University College of Animal Sciences, Hangzhou 310058, China
- Ningbo Academy of Agricultural Sciences, Ningbo 315040, China
| | - Xiamei Kang
- Institute of Preventive Veterinary Sciences and Department of Veterinary Medicine, Zhejiang University College of Animal Sciences, Hangzhou 310058, China
| | - Jiaqi Chen
- Institute of Preventive Veterinary Sciences and Department of Veterinary Medicine, Zhejiang University College of Animal Sciences, Hangzhou 310058, China
| | - Yan Song
- Institute of Preventive Veterinary Sciences and Department of Veterinary Medicine, Zhejiang University College of Animal Sciences, Hangzhou 310058, China
| | - Chenghao Jia
- Institute of Preventive Veterinary Sciences and Department of Veterinary Medicine, Zhejiang University College of Animal Sciences, Hangzhou 310058, China
- Hainan Institute of Zhejiang University, Sanya 572025, China
| | - Lin Teng
- Institute of Preventive Veterinary Sciences and Department of Veterinary Medicine, Zhejiang University College of Animal Sciences, Hangzhou 310058, China
| | - Yanting Tang
- Institute of Preventive Veterinary Sciences and Department of Veterinary Medicine, Zhejiang University College of Animal Sciences, Hangzhou 310058, China
| | - Zhijie Jiang
- Institute of Preventive Veterinary Sciences and Department of Veterinary Medicine, Zhejiang University College of Animal Sciences, Hangzhou 310058, China
| | - Xianqi Peng
- Institute of Preventive Veterinary Sciences and Department of Veterinary Medicine, Zhejiang University College of Animal Sciences, Hangzhou 310058, China
| | - Xiaoxi Tao
- Institute of Preventive Veterinary Sciences and Department of Veterinary Medicine, Zhejiang University College of Animal Sciences, Hangzhou 310058, China
| | - Yiwei Xu
- Institute of Preventive Veterinary Sciences and Department of Veterinary Medicine, Zhejiang University College of Animal Sciences, Hangzhou 310058, China
| | - Linlin Huang
- Institute of Preventive Veterinary Sciences and Department of Veterinary Medicine, Zhejiang University College of Animal Sciences, Hangzhou 310058, China
| | - Xuebin Xu
- Department of Microbiology Laboratory, Shanghai Municipal Center for Disease Control and Prevention, Shanghai 200336, China
| | - Yaohui Xu
- College of Veterinary Medicine, Henan University of Animal Husbandry and Economy, Zhengzhou 450053, China
| | - Tengfei Zhang
- Key Laboratory of Prevention and Control Agents for Animal Bacteriosis, Institute of Animal Husbandry and Veterinary, Hubei Academy of Agricultural Sciences, Wuhan 430064, China
| | - Shenye Yu
- Division of Bacterial Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin 150069, China
| | - Jiansen Gong
- Poultry Institute, Chinese Academy of Agricultural Sciences, Yangzhou 225125, China
| | - Shaohui Wang
- Department of Animal Public Health, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai 200241, China
| | - Yuqing Liu
- Shandong Key Laboratory of Animal Disease Control and Breeding, Institute of Animal Science and Veterinary Medicine, Shandong Academy of Agricultural Sciences, Jinan 250100, China
| | - Guoqiang Zhu
- College of Veterinary Medicine, Yangzhou University, Yangzhou 225009, China
| | - Corinna Kehrenberg
- Institute for Veterinary Food Science, Faculty of Veterinary Medicine, Justus-Liebig University Giessen, Giessen 35392, Germany
| | - François-Xavier Weill
- Institut Pasteur, Université Paris Cité, Unité des bactéries pathogènes entériques, Paris 75724, France
| | - Paul Barrow
- School of Veterinary Medicine, University of Surrey, Guildford GU2 7AL, UK
| | - Yan Li
- Institute of Preventive Veterinary Sciences and Department of Veterinary Medicine, Zhejiang University College of Animal Sciences, Hangzhou 310058, China
- Hainan Institute of Zhejiang University, Sanya 572025, China
| | - Guoping Zhao
- School of Life Science, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou 310024, China
- CAS Key Laboratory of Synthetic Biology, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
- Department of Microbiology and Microbial Engineering, School of Life Sciences, Fudan University, Shanghai 200433, China
| | - Min Yue
- Institute of Preventive Veterinary Sciences and Department of Veterinary Medicine, Zhejiang University College of Animal Sciences, Hangzhou 310058, China
- Hainan Institute of Zhejiang University, Sanya 572025, China
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, National Clinical Research Center for Infectious Diseases, National Medical Center for Infectious Diseases, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou 310003, China
- Zhejiang Provincial Key Laboratory of Preventive Veterinary Medicine, Hangzhou 310058, China
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Abstract
Accumulation of phosphorylated intermediates during cellular metabolism can have wide-ranging toxic effects on many organisms, including humans and the pathogens that infect them. These toxicities can be induced by feeding an upstream metabolite (a sugar, for instance) while simultaneously blocking the appropriate metabolic pathway with either a mutation or an enzyme inhibitor. Here, we survey the toxicities that can arise in the metabolism of glucose, galactose, fructose, fructose-asparagine, glycerol, trehalose, maltose, mannose, mannitol, arabinose, and rhamnose. Select enzymes in these metabolic pathways may serve as novel therapeutic targets. Some are conserved broadly among prokaryotes and eukaryotes (e.g., glucose and galactose) and are therefore unlikely to be viable drug targets. However, others are found only in bacteria (e.g., fructose-asparagine, rhamnose, and arabinose), and one is found in fungi but not in humans (trehalose). We discuss what is known about the mechanisms of toxicity and how resistance is achieved in order to identify the prospects and challenges associated with targeted exploitation of these pervasive metabolic vulnerabilities.
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Evolutionary Stabilization of Cooperative Toxin Production through a Bacterium-Plasmid-Phage Interplay. mBio 2020; 11:mBio.00912-20. [PMID: 32694140 PMCID: PMC7374059 DOI: 10.1128/mbio.00912-20] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Colicins are toxins produced and released by Enterobacteriaceae to kill competitors in the gut. While group A colicins employ a division of labor strategy to liberate the toxin into the environment via colicin-specific lysis, group B colicin systems lack cognate lysis genes. In Salmonella enterica serovar Typhimurium (S. Tm), the group B colicin Ib (ColIb) is released by temperate phage-mediated bacteriolysis. Phage-mediated ColIb release promotes S. Tm fitness against competing Escherichia coli It remained unclear how prophage-mediated lysis is realized in a clonal population of ColIb producers and if prophages contribute to evolutionary stability of toxin release in S. Tm. Here, we show that prophage-mediated lysis occurs in an S. Tm subpopulation only, thereby introducing phenotypic heterogeneity to the system. We established a mathematical model to study the dynamic interplay of S. Tm, ColIb, and a temperate phage in the presence of a competing species. Using this model, we studied long-term evolution of phage lysis rates in a fluctuating infection scenario. This revealed that phage lysis evolves as bet-hedging strategy that maximizes phage spread, regardless of whether colicin is present or not. We conclude that the ColIb system, lacking its own lysis gene, is making use of the evolutionary stable phage strategy to be released. Prophage lysis genes are highly prevalent in nontyphoidal Salmonella genomes. This suggests that the release of ColIb by temperate phages is widespread. In conclusion, our findings shed new light on the evolution and ecology of group B colicin systems.IMPORTANCE Bacteria are excellent model organisms to study mechanisms of social evolution. The production of public goods, e.g., toxin release by cell lysis in clonal bacterial populations, is a frequently studied example of cooperative behavior. Here, we analyze evolutionary stabilization of toxin release by the enteric pathogen Salmonella The release of colicin Ib (ColIb), which is used by Salmonella to gain an edge against competing microbiota following infection, is coupled to bacterial lysis mediated by temperate phages. Here, we show that phage-dependent lysis and subsequent release of colicin and phage particles occurs only in part of the ColIb-expressing Salmonella population. This phenotypic heterogeneity in lysis, which represents an essential step in the temperate phage life cycle, has evolved as a bet-hedging strategy under fluctuating environments such as the gastrointestinal tract. Our findings suggest that prophages can thereby evolutionarily stabilize costly toxin release in bacterial populations.
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Genetic changes associated with the temporal shift in invasive non-typhoidal Salmonella serovars in Bamako Mali. PLoS Negl Trop Dis 2019; 13:e0007297. [PMID: 31170153 PMCID: PMC6592554 DOI: 10.1371/journal.pntd.0007297] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2017] [Revised: 06/25/2019] [Accepted: 03/13/2019] [Indexed: 11/25/2022] Open
Abstract
Background Invasive non-typhoidal Salmonella (iNTS) serovars S. Typhimurium and S. Enteritidis are major etiologic agents of invasive bacterial disease among infants and young children in sub-Saharan Africa, including in Mali. Early studies of iNTS serovars in several countries indicated that S. Typhimurium was more prevalent than S. Enteritidis, including in Mali before 2008. We investigated genomic and associated phenotypic changes associated with an increase in the relative proportion of iNTS caused by S. Enteritidis versus S. Typhimurium in Bamako, Mali, during the period 2002–2012. Methodology/Principal findings Comparative genomics studies identified homologs of tetracycline resistance and arsenic utilization genes that were associated with the temporal shift of serovars causing iNTS shift, along with several hypothetical proteins. These findings, validated through PCR screening and phenotypic assays, provide initial steps towards characterizing the genomic changes consequent to unknown evolutionary pressures associated with the shift in serovar prevalence. Conclusions/Significance This work identified a shift to S. Enteritidis from the more classic S. Typhimurium, associated with iNTS in Bamako, Mali, during the period 2002–2012. This type of shift in underlying iNTS pathogens are of great importance to pediatric public health in endemic regions of sub-Saharan Africa. Additionally, this work demonstrates the utility of combining epidemiologic data, whole genome sequencing, and functional characterization in the laboratory to identify and characterize genomic changes in the isolates that may be involved with the observed shift in circulating iNTS agents. Much remains unknown about the mode of transmission of iNTS or the reservoirs of infection. As such, insight into potential selective pressures on underlying serovars bears importance to public health. Longitudinal studies over the years 2002–2012 identified a shift in the proportion of invasive non-typhoidal Salmonella (iNTS) disease caused by S. Typhimurium or S. Enteritidis in Bamako, Mali. Since S. Enteritidis exhibits a higher rate of fatal cases among the pediatric population than S. Typhimurium, it is important to understand what led to the increased proportion of cases from this serovar. This study examined the genetic changes in S. Enteritidis associated with this serovar shift through comparative genomics and laboratory findings. Through these methods, genes related to tetracycline resistance and arsenic catabolism were associated with the shift in serovars. These findings represent preliminary steps in investigating this underlying shift and determining the long-term repercussions of these changes to the epidemiologic profile of iNTS disease.
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Antimicrobial resistance trends in fecal Salmonella isolates from northern California dairy cattle admitted to a veterinary teaching hospital, 2002-2016. PLoS One 2018; 13:e0199928. [PMID: 29953552 PMCID: PMC6023112 DOI: 10.1371/journal.pone.0199928] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2018] [Accepted: 06/15/2018] [Indexed: 11/19/2022] Open
Abstract
Nontyphoidal Salmonella infections contribute to approximately 1.2 million annual illnesses in the United States. Historical and recent outbreaks have been associated with dairy products, ground beef, and direct contact with cattle. Salmonella antimicrobial resistance (AMR) is a serious concern that can reduce successful treatment of infections, increasing recovery time, medical costs, and mortality rates in humans and animals. This highlights the need to track AMR in Salmonella isolated from cattle to improve treatment plans, manage trends in AMR, and prevent future AMR development. A total of 242 Salmonella isolates were retrieved from 9,162 cattle fecal samples submitted to the University of California, Davis Veterinary Medical Teaching Hospital from 2002 to 2016. These isolates were tested for antimicrobial susceptibility using a standardized broth dilution panel. Multidrug resistance (MDR) to three or more classes of antimicrobials was observed in 50.8% of isolates, and the most common MDR pattern was amoxicillin-ampicillin-cefoxitin-ceftiofur-ceftriaxone-chloramphenicol-streptomycin-tetracycline (23.2%). There were significantly greater odds for antimicrobial resistance to aminoglycosides (OR: 2.03, 95% CI: 1.1–3.7), penicillins (OR: 1.87, 95% CI: 1.007–3.5), and tetracyclines (OR: 1.87, 95% CI: 1.017–3.4) for the 2002–2009 period when compared to the 2010–2016 period. The most prevalent MDR serotypes were Newport (100% MDR, n = 52), Typhimurium (100%, n = 20), and Dublin (71% MDR, n = 46). Risk factors associated with higher odds for isolating MDR Salmonella included isolates from calves when compared to adult cattle (OR: 22.0; 95% C.I.: 3.9–125.7), and isolates obtained from cattle suspect of having salmonellosis versus from the infectious disease control surveillance program (OR:13.7; 95%C.I.: 2.8–66.8). Despite a temporal trend for reduced AMR to most antimicrobial drug classes, a lack of this observed in the 2002–2009 period when compared to the 2010–2016 period for important drug classes such as cephalosporins (OR: 1.6, 95% CI: 0.87–3.1), and a trend for temporal increase in resistant to quinolones drugs (P value 0.004) highlight the relevance of AMR surveillance in cattle with Salmonella infections with the aim of targeting future prophylactic interventions.
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Hiyoshi H, Tiffany CR, Bronner DN, Bäumler AJ. Typhoidal Salmonella serovars: ecological opportunity and the evolution of a new pathovar. FEMS Microbiol Rev 2018; 42:527-541. [DOI: 10.1093/femsre/fuy024] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2018] [Accepted: 05/19/2018] [Indexed: 12/20/2022] Open
Affiliation(s)
- Hirotaka Hiyoshi
- Department of Medial Microbiology and Immunology, School of Medicine, University of California Davis, Davis, CA 95616, USA
| | - Connor R Tiffany
- Department of Medial Microbiology and Immunology, School of Medicine, University of California Davis, Davis, CA 95616, USA
| | - Denise N Bronner
- Department of Medial Microbiology and Immunology, School of Medicine, University of California Davis, Davis, CA 95616, USA
| | - Andreas J Bäumler
- Department of Medial Microbiology and Immunology, School of Medicine, University of California Davis, Davis, CA 95616, USA
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Feasey NA, Hadfield J, Keddy KH, Dallman TJ, Jacobs J, Deng X, Wigley P, Barquist L, Langridge GC, Feltwell T, Harris SR, Mather AE, Fookes M, Aslett M, Msefula C, Kariuki S, Maclennan CA, Onsare RS, Weill FX, Le Hello S, Smith AM, McClelland M, Desai P, Parry CM, Cheesbrough J, French N, Campos J, Chabalgoity JA, Betancor L, Hopkins KL, Nair S, Humphrey TJ, Lunguya O, Cogan TA, Tapia MD, Sow SO, Tennant SM, Bornstein K, Levine MM, Lacharme-Lora L, Everett DB, Kingsley RA, Parkhill J, Heyderman RS, Dougan G, Gordon MA, Thomson NR. Distinct Salmonella Enteritidis lineages associated with enterocolitis in high-income settings and invasive disease in low-income settings. Nat Genet 2016; 48:1211-1217. [PMID: 27548315 PMCID: PMC5047355 DOI: 10.1038/ng.3644] [Citation(s) in RCA: 136] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2015] [Accepted: 07/15/2016] [Indexed: 11/15/2022]
Abstract
An epidemiological paradox surrounds Salmonella enterica serovar Enteritidis. In high-income settings, it has been responsible for an epidemic of poultry-associated, self-limiting enterocolitis, whereas in sub-Saharan Africa it is a major cause of invasive nontyphoidal Salmonella disease, associated with high case fatality. By whole-genome sequence analysis of 675 isolates of S. Enteritidis from 45 countries, we show the existence of a global epidemic clade and two new clades of S. Enteritidis that are geographically restricted to distinct regions of Africa. The African isolates display genomic degradation, a novel prophage repertoire, and an expanded multidrug resistance plasmid. S. Enteritidis is a further example of a Salmonella serotype that displays niche plasticity, with distinct clades that enable it to become a prominent cause of gastroenteritis in association with the industrial production of eggs and of multidrug-resistant, bloodstream-invasive infection in Africa.
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Affiliation(s)
- Nicholas A Feasey
- Liverpool School of Tropical Medicine, Liverpool, UK
- Wellcome Trust Sanger Institute, Cambridge, UK
- Malawi Liverpool Wellcome Trust Clinical Research Programme, University of Malawi College of Medicine, Blantyre, Malawi
- Institute of Infection and Global Health, University of Liverpool, Liverpool, UK
| | | | - Karen H Keddy
- Centre for Enteric Diseases, National Institute for Communicable Diseases, Johannesburg, South Africa
- Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Timothy J Dallman
- Gastrointestinal Bacteria Reference Unit, Public Health England, Colindale, UK
| | - Jan Jacobs
- Institute of Tropical Medicine, Antwerp, Belgium
- Department of Microbiology and Immunology, University of Leuven, Belgium
| | - Xiangyu Deng
- Center for Food Safety, Department of Food Science and Technology, University of Georgia
- Centers for Disease Control and Prevention, Atlanta, USA
| | - Paul Wigley
- Institute of Infection and Global Health, University of Liverpool, Liverpool, UK
| | - Lars Barquist
- Institute for Molecular Infection Biology, University of Würzburg, Würzburg, Germany
| | | | | | | | | | | | | | - Chisomo Msefula
- Malawi Liverpool Wellcome Trust Clinical Research Programme, University of Malawi College of Medicine, Blantyre, Malawi
- University of Malawi, The College of Medicine, Blantyre, Malawi
| | - Samuel Kariuki
- Centre for Microbiology Research, Kenya Medical Research Institute, Nairobi, Kenya
| | - Calman A Maclennan
- Wellcome Trust Sanger Institute, Cambridge, UK
- Jenner Institute, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Robert S Onsare
- Centre for Microbiology Research, Kenya Medical Research Institute, Nairobi, Kenya
| | | | | | - Anthony M Smith
- Centre for Enteric Diseases, National Institute for Communicable Diseases, Johannesburg, South Africa
| | - Michael McClelland
- Department of Microbiology and Molecular Genetics, University of California, Irvine, CA, USA
| | - Prerak Desai
- Department of Microbiology and Molecular Genetics, University of California, Irvine, CA, USA
| | - Christopher M Parry
- Liverpool School of Tropical Medicine, Liverpool, UK
- London School of Hygiene & Tropical Medicine, London, UK
| | - John Cheesbrough
- Department of Epidemiology and Population Health, University of Liverpool, Liverpool, UK
| | - Neil French
- Institute of Infection and Global Health, University of Liverpool, Liverpool, UK
| | - Josefina Campos
- Enteropathogen Division, Administración Nacional de Laboratorios e Institutos de Salud (ANLIS) Carlos G. Malbran Institute, Buenos Aires, Argentina
| | - Jose A Chabalgoity
- Instituto de Higiene, Facultad de Medicina, Universidad de la Republica, Uruguay
| | - Laura Betancor
- Instituto de Higiene, Facultad de Medicina, Universidad de la Republica, Uruguay
| | - Katie L Hopkins
- Antimicrobial Resistance and Healthcare-Associated Infections Reference Unit, Public Health England, Colindale, UK
| | - Satheesh Nair
- Gastrointestinal Bacteria Reference Unit, Public Health England, Colindale, UK
| | | | - Octavie Lunguya
- National Institute of Biomedical Research, Kinshasa, the Democratic Republic of the Congo
- University Hospital of Kinshasa, Kinshasa, the Democratic Republic of the Congo
| | - Tristan A Cogan
- School of Veterinary Sciences, University of Bristol, Bristol, UK
| | - Milagritos D Tapia
- Center for Vaccine Development, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Samba O Sow
- Centre pour le Développement des Vaccins, Bamako, Mali
| | - Sharon M Tennant
- Center for Vaccine Development, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Kristin Bornstein
- Center for Vaccine Development, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Myron M Levine
- Center for Vaccine Development, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Lizeth Lacharme-Lora
- Institute of Infection and Global Health, University of Liverpool, Liverpool, UK
| | - Dean B Everett
- Institute of Infection and Global Health, University of Liverpool, Liverpool, UK
| | - Robert A Kingsley
- Wellcome Trust Sanger Institute, Cambridge, UK
- Institute of Food Research, Colney, Norwich, UK
| | | | - Robert S Heyderman
- Malawi Liverpool Wellcome Trust Clinical Research Programme, University of Malawi College of Medicine, Blantyre, Malawi
- Division of Infection and Immunity, University College London, London, UK
| | | | - Melita A Gordon
- Malawi Liverpool Wellcome Trust Clinical Research Programme, University of Malawi College of Medicine, Blantyre, Malawi
- Institute of Infection and Global Health, University of Liverpool, Liverpool, UK
| | - Nicholas R Thomson
- Wellcome Trust Sanger Institute, Cambridge, UK
- London School of Hygiene & Tropical Medicine, London, UK
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The Periplasmic Nitrate Reductase NapABC Supports Luminal Growth of Salmonella enterica Serovar Typhimurium during Colitis. Infect Immun 2015; 83:3470-8. [PMID: 26099579 DOI: 10.1128/iai.00351-15] [Citation(s) in RCA: 88] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2015] [Accepted: 06/12/2015] [Indexed: 02/03/2023] Open
Abstract
The food-borne pathogen Salmonella enterica serovar Typhimurium benefits from acute inflammation in part by using host-derived nitrate to respire anaerobically and compete successfully with the commensal microbes during growth in the intestinal lumen. The S. Typhimurium genome contains three nitrate reductases, encoded by the narGHI, narZYV, and napABC genes. Work on homologous genes present in Escherichia coli suggests that nitrate reductase A, encoded by the narGHI genes, is the main enzyme promoting growth on nitrate as an electron acceptor in anaerobic environments. Using a mouse colitis model, we found, surprisingly, that S. Typhimurium strains with defects in either nitrate reductase A (narG mutant) or the regulator inducing its transcription in the presence of high concentrations of nitrate (narL mutant) exhibited growth comparable to that of wild-type S. Typhimurium. In contrast, a strain lacking a functional periplasmic nitrate reductase (napA mutant) exhibited a marked growth defect in the lumen of the colon. In E. coli, the napABC genes are transcribed maximally under anaerobic growth conditions in the presence of low nitrate concentrations. Inactivation of narP, encoding a response regulator that activates napABC transcription in response to low nitrate concentrations, significantly reduced the growth of S. Typhimurium in the gut lumen. Cecal nitrate measurements suggested that the murine cecum is a nitrate-limited environment. Collectively, our results suggest that S. Typhimurium uses the periplasmic nitrate reductase to support its growth on the low nitrate concentrations encountered in the gut, a strategy that may be shared with other enteric pathogens.
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