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Segura A, Bertin Y, Durand A, Benbakkar M, Forano E. Transcriptional analysis reveals specific niche factors and response to environmental stresses of enterohemorrhagic Escherichia coli O157:H7 in bovine digestive contents. BMC Microbiol 2021; 21:284. [PMID: 34663220 PMCID: PMC8524897 DOI: 10.1186/s12866-021-02343-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Accepted: 09/24/2021] [Indexed: 02/08/2023] Open
Abstract
Background Enterohemorrhagic Escherichia coli (EHEC) are responsible for severe diseases in humans, and the ruminant digestive tract is considered as their main reservoir. Their excretion in bovine feces leads to the contamination of foods and the environment. Thus, providing knowledge of processes used by EHEC to survive and/or develop all along the bovine gut represents a major step for strategies implementation. Results We compared the transcriptome of the reference EHEC strain EDL933 incubated in vitro in triplicate samples in sterile bovine rumen, small intestine and rectum contents with that of the strain grown in an artificial medium using RNA-sequencing (RNA-seq), focusing on genes involved in stress response, adhesion systems including the LEE, iron uptake, motility and chemotaxis. We also compared expression of these genes in one digestive content relative to the others. In addition, we quantified short chain fatty acids and metal ions present in the three digestive contents. RNA-seq data first highlighted response of EHEC EDL933 to unfavorable physiochemical conditions encountered during its transit through the bovine gut lumen. Seventy-eight genes involved in stress responses including drug export, oxidative stress and acid resistance/pH adaptation were over-expressed in all the digestive contents compared with artificial medium. However, differences in stress fitness gene expression were observed depending on the digestive segment, suggesting that these differences were due to distinct physiochemical conditions in the bovine digestive contents. EHEC activated genes encoding three toxin/antitoxin systems in rumen content and many gene clusters involved in motility and chemotaxis in rectum contents. Genes involved in iron uptake and utilization were mostly down-regulated in all digestive contents compared with artificial medium, but feo genes were over-expressed in rumen and small intestine compared with rectum. The five LEE operons were more expressed in rectum than in rumen content, and LEE1 was also more expressed in rectum than in small intestine content. Conclusion Our results highlight various strategies that EHEC may implement to survive in the gastrointestinal environment of cattle. These data could also help defining new targets to limit EHEC O157:H7 carriage and shedding by cattle. Supplementary Information The online version contains supplementary material available at 10.1186/s12866-021-02343-7.
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Affiliation(s)
- Audrey Segura
- Université Clermont Auvergne, INRAE, MEDIS 0454, F-63000, Clermont-Ferrand, France
| | - Yolande Bertin
- Université Clermont Auvergne, INRAE, MEDIS 0454, F-63000, Clermont-Ferrand, France
| | - Alexandra Durand
- Université Clermont Auvergne, INRAE, MEDIS 0454, F-63000, Clermont-Ferrand, France
| | - Mhammed Benbakkar
- Université Clermont Auvergne, CNRS, IRD, OPGC, Laboratoire Magmas et Volcans, F-63000, Clermont-Ferrand, France
| | - Evelyne Forano
- Université Clermont Auvergne, INRAE, MEDIS 0454, F-63000, Clermont-Ferrand, France.
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2
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Ramamurthy T, Nandy RK, Mukhopadhyay AK, Dutta S, Mutreja A, Okamoto K, Miyoshi SI, Nair GB, Ghosh A. Virulence Regulation and Innate Host Response in the Pathogenicity of Vibrio cholerae. Front Cell Infect Microbiol 2020; 10:572096. [PMID: 33102256 PMCID: PMC7554612 DOI: 10.3389/fcimb.2020.572096] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Accepted: 08/19/2020] [Indexed: 02/06/2023] Open
Abstract
The human pathogen Vibrio cholerae is the causative agent of severe diarrheal disease known as cholera. Of the more than 200 "O" serogroups of this pathogen, O1 and O139 cause cholera outbreaks and epidemics. The rest of the serogroups, collectively known as non-O1/non-O139 cause sporadic moderate or mild diarrhea and also systemic infections. Pathogenic V. cholerae circulates between nutrient-rich human gut and nutrient-deprived aquatic environment. As an autochthonous bacterium in the environment and as a human pathogen, V. cholerae maintains its survival and proliferation in these two niches. Growth in the gastrointestinal tract involves expression of several genes that provide bacterial resistance against host factors. An intricate regulatory program involving extracellular signaling inputs is also controlling this function. On the other hand, the ability to store carbon as glycogen facilitates bacterial fitness in the aquatic environment. To initiate the infection, V. cholerae must colonize the small intestine after successfully passing through the acid barrier in the stomach and survive in the presence of bile and antimicrobial peptides in the intestinal lumen and mucus, respectively. In V. cholerae, virulence is a multilocus phenomenon with a large functionally associated network. More than 200 proteins have been identified that are functionally linked to the virulence-associated genes of the pathogen. Several of these genes have a role to play in virulence and/or in functions that have importance in the human host or the environment. A total of 524 genes are differentially expressed in classical and El Tor strains, the two biotypes of V. cholerae serogroup O1. Within the host, many immune and biological factors are able to induce genes that are responsible for survival, colonization, and virulence. The innate host immune response to V. cholerae infection includes activation of several immune protein complexes, receptor-mediated signaling pathways, and other bactericidal proteins. This article presents an overview of regulation of important virulence factors in V. cholerae and host response in the context of pathogenesis.
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Affiliation(s)
| | - Ranjan K Nandy
- Division of Bacteriology, National Institute of Cholera and Enteric Diseases, Kolkata, India
| | - Asish K Mukhopadhyay
- Division of Bacteriology, National Institute of Cholera and Enteric Diseases, Kolkata, India
| | - Shanta Dutta
- Division of Bacteriology, National Institute of Cholera and Enteric Diseases, Kolkata, India
| | - Ankur Mutreja
- Global Health-Infectious Diseases, Department of Medicine, University of Cambridge, Cambridge, United Kingdom
| | - Keinosuke Okamoto
- Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan.,Collaborative Research Center of Okayama University for Infectious Diseases in India, National Institute of Cholera and Enteric Diseases, Kolkata, India
| | - Shin-Ichi Miyoshi
- Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan
| | - G Balakrish Nair
- Microbiome Laboratory, Rajiv Gandhi Centre for Biotechnology, Thiruvananthapuram, India
| | - Amit Ghosh
- Division of Bacteriology, National Institute of Cholera and Enteric Diseases, Kolkata, India
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3
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Xi D, Li Y, Yan J, Li Y, Wang X, Cao B. Small RNA coaR contributes to intestinal colonization in Vibrio cholerae via the two-component system EnvZ/OmpR. Environ Microbiol 2020; 22:4231-4243. [PMID: 31868254 DOI: 10.1111/1462-2920.14906] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Accepted: 12/20/2019] [Indexed: 11/30/2022]
Abstract
Vibrio cholerae is a waterborne bacterium responsible for worldwide outbreaks of acute and fatal cholera. Recently, small regulatory RNAs (sRNAs) have become increasingly recognized as important regulators of virulence gene expression in response to environmental signals. In this study, we determined that two-component system EnvZ/OmpR was required for intestinal colonization in V. cholerae O1 EI Tor strain E12382. Analysis of the characteristics of OmpR revealed a potential binding site in the intergenic region between vc1470 and vc1471, and qRT-PCR showed that expression of the intergenic region increased 5.3-fold in the small intestine compared to LB medium. Race and northern blot assays were performed and demonstrated a new sRNA, coaR (cholerae osmolarity and acidity related regulatory RNA). A ΔcoaR mutant showed a deficient colonization ability in small intestine with CI of 0.15. We identified a target of coaR, tcpI, a negative regulator of the major pilin subunit of TcpA. The ΔtcpI mutant has an increased colonization with CI of 3.16. The expression of coaR increased 2.8-fold and 3.3-fold under relative acidic and hypertonic condition. In summary, coaR was induced under the condition of high osmolarity and acid stress via EnvZ/OmpR and explained that tcpI relieves pH-mediated repression of toxin co-regulated pilus synthesis.
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Affiliation(s)
- Daoyi Xi
- TEDA Institute of Biological Sciences and Biotechnology, Nankai University, Tianjin, 300457, China.,Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Nankai University, Tianjin, 300457, China.,Tianjin Research Center for Functional Genomics and Biochips, TEDA College, Nankai University, Tianjin, 300457, China.,Tianjin Key Laboratory of Microbial Functional Genomics, TEDA College, Nankai University, Tianjin, 300457, China
| | - Yujia Li
- TEDA Institute of Biological Sciences and Biotechnology, Nankai University, Tianjin, 300457, China.,Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Nankai University, Tianjin, 300457, China.,Tianjin Research Center for Functional Genomics and Biochips, TEDA College, Nankai University, Tianjin, 300457, China.,Tianjin Key Laboratory of Microbial Functional Genomics, TEDA College, Nankai University, Tianjin, 300457, China
| | - Junxiang Yan
- TEDA Institute of Biological Sciences and Biotechnology, Nankai University, Tianjin, 300457, China.,Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Nankai University, Tianjin, 300457, China.,Tianjin Research Center for Functional Genomics and Biochips, TEDA College, Nankai University, Tianjin, 300457, China.,Tianjin Key Laboratory of Microbial Functional Genomics, TEDA College, Nankai University, Tianjin, 300457, China
| | - Yuehua Li
- TEDA Institute of Biological Sciences and Biotechnology, Nankai University, Tianjin, 300457, China.,Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Nankai University, Tianjin, 300457, China.,Tianjin Research Center for Functional Genomics and Biochips, TEDA College, Nankai University, Tianjin, 300457, China.,Tianjin Key Laboratory of Microbial Functional Genomics, TEDA College, Nankai University, Tianjin, 300457, China
| | - Xiaochen Wang
- TEDA Institute of Biological Sciences and Biotechnology, Nankai University, Tianjin, 300457, China.,Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Nankai University, Tianjin, 300457, China.,Tianjin Research Center for Functional Genomics and Biochips, TEDA College, Nankai University, Tianjin, 300457, China.,Tianjin Key Laboratory of Microbial Functional Genomics, TEDA College, Nankai University, Tianjin, 300457, China
| | - Boyang Cao
- TEDA Institute of Biological Sciences and Biotechnology, Nankai University, Tianjin, 300457, China.,Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Nankai University, Tianjin, 300457, China.,Tianjin Research Center for Functional Genomics and Biochips, TEDA College, Nankai University, Tianjin, 300457, China.,Tianjin Key Laboratory of Microbial Functional Genomics, TEDA College, Nankai University, Tianjin, 300457, China
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4
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Peterson KM, Gellings PS. Multiple intraintestinal signals coordinate the regulation of Vibrio cholerae virulence determinants. Pathog Dis 2018; 76:4791527. [PMID: 29315383 DOI: 10.1093/femspd/ftx126] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2017] [Accepted: 12/27/2017] [Indexed: 12/17/2022] Open
Abstract
Vibrio cholerae is a Gram-negative motile bacterium capable of causing fatal pandemic disease in humans via oral ingestion of contaminated water or food. Within the human intestine, the motile vibrios must evade the innate host defense mechanisms, penetrate the mucus layer covering the small intestine, adhere to and multiply on the surface of the microvilli and cause disease via the action of cholera toxin. The explosive diarrhea associated with V. cholerae intestinal colonization leads to dissemination of the vibrios back into the environment to complete this phase of the life cycle. The host phase of the vibrio life cycle is made possible via the concerted action of a signaling cascade that controls the synthesis of V. cholerae colonization determinants. These virulence proteins are coordinately synthesized in response to specific host signals that are still largely undefined. A more complete understanding of the molecular events involved in the V. cholerae recognition of intraintestinal signals and the subsequent transcriptional response will provide important information regarding how pathogenic bacteria establish infection and provide novel methods for treating and/or preventing bacterial infections such as Asiatic cholera. This review will summarize what is currently known in regard to host intraintestinal signals that inform the complex ToxR regulatory cascade in order to coordinate in a spatial and temporal fashion virulence protein synthesis within the human small intestine.
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Affiliation(s)
- Kenneth M Peterson
- Department of Microbiology and Immunology, Louisiana State University Health Science Center, Shreveport, LA 71130, USA
| | - Patrick S Gellings
- Department of Microbiology and Immunology, Louisiana State University Health Science Center, Shreveport, LA 71130, USA
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5
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Valiente E, Davies C, Mills DC, Getino M, Ritchie JM, Wren BW. Vibrio cholerae accessory colonisation factor AcfC: a chemotactic protein with a role in hyperinfectivity. Sci Rep 2018; 8:8390. [PMID: 29849063 PMCID: PMC5976639 DOI: 10.1038/s41598-018-26570-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2017] [Accepted: 05/10/2018] [Indexed: 12/25/2022] Open
Abstract
Vibrio cholerae O1 El Tor is an aquatic Gram-negative bacterium responsible for the current seventh pandemic of the diarrheal disease, cholera. A previous whole-genome analysis on V. cholerae O1 El Tor strains from the 2010 epidemic in Pakistan showed that all strains contained the V. cholerae pathogenicity island-1 and the accessory colonisation gene acfC (VC_0841). Here we show that acfC possess an open reading frame of 770 bp encoding a protein with a predicted size of 28 kDa, which shares high amino acid similarity with two adhesion proteins found in other enteropathogens, including Paa in serotype O45 porcine enteropathogenic Escherichia coli and PEB3 in Campylobacter jejuni. Using a defined acfC deletion mutant, we studied the specific role of AcfC in V. cholerae O1 El Tor environmental survival, colonisation and virulence in two infection model systems (Galleria mellonella and infant rabbits). Our results indicate that AcfC might be a periplasmic sulfate-binding protein that affects chemotaxis towards mucin and bacterial infectivity in the infant rabbit model of cholera. Overall, our findings suggest that AcfC contributes to the chemotactic response of WT V. cholerae and plays an important role in defining the overall distribution of the organism within the intestine.
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Affiliation(s)
- Esmeralda Valiente
- Department of Pathogen Molecular Biology, London School of Hygiene and Tropical Medicine, Keppel Street, WC1E 7HT, London, UK
| | - Cadi Davies
- Department of Pathogen Molecular Biology, London School of Hygiene and Tropical Medicine, Keppel Street, WC1E 7HT, London, UK
| | - Dominic C Mills
- Department of Pathogen Molecular Biology, London School of Hygiene and Tropical Medicine, Keppel Street, WC1E 7HT, London, UK.,Robert Frederick Smith School of Chemical and Biomolecular Engineering, Cornell University, Olin Hall, Ithaca, NY, USA
| | - Maria Getino
- Department of Microbial Sciences, Faculty of Health and Medical Sciences, University of Surrey, Guildford, GU2 7XH, UK
| | - Jennifer M Ritchie
- Department of Microbial Sciences, Faculty of Health and Medical Sciences, University of Surrey, Guildford, GU2 7XH, UK
| | - Brendan W Wren
- Department of Pathogen Molecular Biology, London School of Hygiene and Tropical Medicine, Keppel Street, WC1E 7HT, London, UK.
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6
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Greer-Phillips SE, Sukomon N, Chua TK, Johnson MS, Crane BR, Watts KJ. THE AER2 RECEPTOR FROM VIBRIO CHOLERAE IS A DUAL PAS-HEME OXYGEN SENSOR. Mol Microbiol 2018; 109:209-224. [PMID: 29719085 DOI: 10.1111/mmi.13978] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2018] [Revised: 04/28/2018] [Accepted: 04/29/2018] [Indexed: 12/16/2022]
Abstract
The diarrheal pathogen Vibrio cholerae navigates complex environments using three chemosensory systems and 44-45 chemoreceptors. Chemosensory cluster II modulates chemotaxis, whereas clusters I and III have unknown functions. Ligands have been identified for only five V. cholerae chemoreceptors. Here we report that the cluster III receptor, VcAer2, binds and responds to O2 . VcAer2 is an ortholog of Pseudomonas aeruginosa Aer2 (PaAer2), but differs in that VcAer2 has two, rather than one, N-terminal PAS domain. We have determined that both PAS1 and PAS2 form homodimers and bind penta-coordinate b-type heme via an Eη-His residue. Heme binding to PAS1 required the entire PAS core, but receptor function also required the N-terminal cap. PAS2 functioned as an O2 -sensor [Kd(O2) , 19 μM], utilizing the same Iβ Trp (W276) as PaAer2 to stabilize O2 . The crystal structure of PAS2-W276L was similar to that of PaAer2-PAS, but resided in an active conformation mimicking the ligand-bound state, consistent with its signal-on phenotype. PAS1 also bound O2 [Kd(O2), 12 μM], although O2 binding was stabilized by either a Trp or Tyr residue. Moreover, PAS1 appeared to function as a signal modulator, regulating O2 -mediated signaling from PAS2, and resulting in activation of the cluster III chemosensory pathway. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Suzanne E Greer-Phillips
- Division of Microbiology and Molecular Genetics, Loma Linda University, Loma Linda, CA, 92350, USA
| | - Nattakan Sukomon
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY, 14850, USA
| | - Teck Khiang Chua
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY, 14850, USA
| | - Mark S Johnson
- Division of Microbiology and Molecular Genetics, Loma Linda University, Loma Linda, CA, 92350, USA
| | - Brian R Crane
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY, 14850, USA
| | - Kylie J Watts
- Division of Microbiology and Molecular Genetics, Loma Linda University, Loma Linda, CA, 92350, USA
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