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Kalalah AA, Koenig SSK, Bono JL, Bosilevac JM, Eppinger M. Pathogenomes and virulence profiles of representative big six non-O157 serogroup Shiga toxin-producing Escherichia coli. Front Microbiol 2024; 15:1364026. [PMID: 38562479 PMCID: PMC10982417 DOI: 10.3389/fmicb.2024.1364026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2024] [Accepted: 02/29/2024] [Indexed: 04/04/2024] Open
Abstract
Shiga toxin (Stx)-producing Escherichia coli (STEC) of non-O157:H7 serotypes are responsible for global and widespread human food-borne disease. Among these serogroups, O26, O45, O103, O111, O121, and O145 account for the majority of clinical infections and are colloquially referred to as the "Big Six." The "Big Six" strain panel we sequenced and analyzed in this study are reference type cultures comprised of six strains representing each of the non-O157 STEC serogroups curated and distributed by the American Type Culture Collection (ATCC) as a resource to the research community under panel number ATCC MP-9. The application of long- and short-read hybrid sequencing yielded closed chromosomes and a total of 14 plasmids of diverse functions. Through high-resolution comparative phylogenomics, we cataloged the shared and strain-specific virulence and resistance gene content and established the close relationship of serogroup O26 and O103 strains featuring flagellar H-type 11. Virulence phenotyping revealed statistically significant differences in the Stx-production capabilities that we found to be correlated to the strain's individual stx-status. Among the carried Stx1a, Stx2a, and Stx2d phages, the Stx2a phage is by far the most responsive upon RecA-mediated phage mobilization, and in consequence, stx2a + isolates produced the highest-level of toxin in this panel. The availability of high-quality closed genomes for this "Big Six" reference set, including carried plasmids, along with the recorded genomic virulence profiles and Stx-production phenotypes will provide a valuable foundation to further explore the plasticity in evolutionary trajectories in these emerging non-O157 STEC lineages, which are major culprits of human food-borne disease.
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Affiliation(s)
- Anwar A. Kalalah
- Department of Molecular Microbiology and Immunology, University of Texas at San Antonio, San Antonio, TX, United States
- South Texas Center for Emerging Infectious Diseases (STCEID), San Antonio, TX, United States
| | - Sara S. K. Koenig
- Department of Molecular Microbiology and Immunology, University of Texas at San Antonio, San Antonio, TX, United States
- South Texas Center for Emerging Infectious Diseases (STCEID), San Antonio, TX, United States
| | - James L. Bono
- U.S. Department of Agriculture (USDA), Agricultural Research Service (ARS), U.S. Meat Animal Research Center, Clay Center, NE, United States
| | - Joseph M. Bosilevac
- U.S. Department of Agriculture (USDA), Agricultural Research Service (ARS), U.S. Meat Animal Research Center, Clay Center, NE, United States
| | - Mark Eppinger
- Department of Molecular Microbiology and Immunology, University of Texas at San Antonio, San Antonio, TX, United States
- South Texas Center for Emerging Infectious Diseases (STCEID), San Antonio, TX, United States
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L A LA, Waturangi DE. Application of BI-EHEC and BI-EPEC bacteriophages to control enterohemorrhagic and enteropathogenic escherichia coli on various food surfaces. BMC Res Notes 2023; 16:102. [PMID: 37312167 DOI: 10.1186/s13104-023-06371-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Accepted: 05/25/2023] [Indexed: 06/15/2023] Open
Abstract
OBJECTIVES The purposes of this study were to determine the Efficiency of Plating (EOP) value of Bacteriophage BI-EHEC and BI-EPEC and to evaluate the application of these bacteriophages in reducing population of EHEC and EPEC on various food samples. RESULTS In this study, we used bacteriophage BI-EHEC and BI-EPEC, which were isolated from previous study. Both phages were tested with other multiple pathotypes of intestinal pathogenic E. coli to determine the efficiency of plating. BI-EHEC had high efficiency toward ETEC with an EOP value of 2.95 but low efficiency toward EHEC with an EOP value of 0.10, while BI-EPEC had high efficiency toward EHEC and ETEC with EOP values of 1.10 and 1.21, respectively. As biocontrol agents, both bacteriophages able to reduce CFU of EHEC and EPEC in several food samples using 1 and 6-days incubation times at 4 [Formula: see text]. BI-EHEC reduced the number of EHEC with an overall percentage of bacterial reduction value above 0.13 log10, while BI-EPEC reduced number of EPEC with reduction value above 0.33 log10.
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Affiliation(s)
- Leny Agustina L A
- Faculty of Biotechnology, Atma Jaya Catholic University of Indonesia, Jalan Jenderal Sudirman 51 Jakarta, 12930, South Jakarta, Indonesia
| | - Diana Elizabeth Waturangi
- Faculty of Biotechnology, Atma Jaya Catholic University of Indonesia, Jalan Jenderal Sudirman 51 Jakarta, 12930, South Jakarta, Indonesia.
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Izquierdo M, Lopez J, Gallardo P, Vidal RM, Ossa JC, Farfan MJ. Bacteria from gut microbiota associated with diarrheal infections in children promote virulence of Shiga toxin-producing and enteroaggregative Escherichia coli pathotypes. Front Cell Infect Microbiol 2022; 12:867205. [PMID: 36017363 PMCID: PMC9396624 DOI: 10.3389/fcimb.2022.867205] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Accepted: 07/07/2022] [Indexed: 11/26/2022] Open
Abstract
Background Diarrheagenic E. coli (DEC) pathogenicity relies on the interaction of bacteria with the host’s gut environment, which is regulated by the resident microbiota. Previously, we identified indicative bacterial species of gut microbiota in DEC-positive stool samples from children. Here, we evaluated the role of two indicative species, Citrobacter werkmanii (CW) and Escherichia albertii (EA), in the virulence of two DEC pathotypes, Shiga toxin-producing (STEC) and enteroaggregative (EAEC) Escherichia coli. Methods We determined the effect of supernatants obtained from CW and EA cultures on the gene expression of STEC strain 86-24 and EAEC strain 042 by RNA-seq analysis. We evaluated IL-8 secretion from T84 cells infected with these DEC strains in the presence or absence of the supernatant from EA. The effect of the supernatant from EA on the growth and adherence of STEC and EAEC to cells was also evaluated. Finally, we studied the effect of the EA supernatant on the STEC-induced inflammation mediated by the long polar fimbriae (Lpf) in T84 cells and the expression of plasmid-encoded toxin (Pet) in EAEC. Results RNA-seq analysis revealed that several virulence factors in STEC and EAEC were upregulated in the presence of supernatants from CW and EA. Interestingly, an increase in the secretion of IL-8 was observed in cells infected with STEC or EAEC in the presence of a supernatant from EA. Similar results were observed with the supernatants obtained from clinical strains of E. albertii. The supernatant from EA had no effect on the growth of STEC and EAEC, or on the ability of these DEC strains to adhere to cells. We found that Pet toxin in EAEC was upregulated in the presence of a supernatant from EA. In STEC, using mutant strains for Lpf fimbriae, our data suggested that these fimbriae might be participating in the increase in IL-8 induced by STEC in cells in the presence of a supernatant from EA. Conclusion Supernatant obtained from an indicative species of DEC-positive diarrhea could modulate gene expression in STEC and EAEC, and IL-8 secretion induced by these bacteria. These data provide new insights into the effect of gut microbiota species in the pathogenicity of STEC and EAEC.
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Affiliation(s)
- Mariana Izquierdo
- Departamento de Pediatría y Cirugía Infantil, Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Joaquín Lopez
- Departamento de Pediatría y Cirugía Infantil, Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Pablo Gallardo
- Departamento de Pediatría y Cirugía Infantil, Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Roberto M. Vidal
- Programa de Microbiología y Micología, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Juan C. Ossa
- Departamento de Pediatría y Cirugía Infantil, Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Mauricio J. Farfan
- Departamento de Pediatría y Cirugía Infantil, Facultad de Medicina, Universidad de Chile, Santiago, Chile
- *Correspondence: Mauricio J. Farfan,
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Allué-Guardia A, Koenig SSK, Martinez RA, Rodriguez AL, Bosilevac JM, Feng† P, Eppinger M. Pathogenomes and variations in Shiga toxin production among geographically distinct clones of Escherichia coli O113:H21. Microb Genom 2022; 8. [PMID: 35394418 PMCID: PMC9453080 DOI: 10.1099/mgen.0.000796] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Infections with globally disseminated Shiga toxin-producing Escherichia coli (STEC) of the O113:H21 serotype can progress to severe clinical complications, such as hemolytic uremic syndrome (HUS). Two phylogeographically distinct clonal complexes have been established by multi locus sequence typing (MLST). Infections with ST-820 isolates circulating exclusively in Australia have caused severe human disease, such as HUS. Conversely, ST-223 isolates prevalent in the US and outside Australia seem to rarely cause severe human disease but are frequent contaminants. Following a genomic epidemiology approach, we wanted to gain insights into the underlying cause for this disparity. We examined the plasticity in the genome make-up and Shiga toxin production in a collection of 20 ST-820 and ST-223 strains isolated from produce, the bovine reservoir, and clinical cases. STEC are notorious for assembly into fragmented draft sequences when using short-read sequencing technologies due to the extensive and partly homologous phage complement. The application of long-read technology (LRT) sequencing yielded closed reference chromosomes and plasmids for two representative ST-820 and ST-223 strains. The established high-resolution framework, based on whole genome alignments, single nucleotide polymorphism (SNP)-typing and MLST, includes the chromosomes and plasmids of other publicly available O113:H21 sequences and allowed us to refine the phylogeographical boundaries of ST-820 and ST-223 complex isolates and to further identify a historic non-shigatoxigenic strain from Mexico as a quasi-intermediate. Plasmid comparison revealed strong correlations between the strains' featured pO113 plasmid genotypes and chromosomally inferred ST, which suggests coevolution of the chromosome and virulence plasmids. Our pathogenicity assessment revealed statistically significant differences in the Stx2a-production capabilities of ST-820 as compared to ST-223 strains under RecA-induced Stx phage mobilization, a condition that mimics Stx-phage induction. These observations suggest that ST-820 strains may confer an increased pathogenic potential in line with the strain-associated epidemiological metadata. Still, some of the tested ST-223 cultures sourced from contaminated produce or the bovine reservoir also produced Stx at levels comparable to those of ST-820 isolates, which calls for awareness and for continued surveillance of this lineage.
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Affiliation(s)
- Anna Allué-Guardia
- Department of Molecular Microbiology and Immunology, University of Texas at San Antonio, San Antonio, TX, USA
- South Texas Center for Emerging Infectious Diseases (STCEID), San Antonio, TX, USA
| | - Sara S. K. Koenig
- Department of Molecular Microbiology and Immunology, University of Texas at San Antonio, San Antonio, TX, USA
- South Texas Center for Emerging Infectious Diseases (STCEID), San Antonio, TX, USA
| | - Ricardo A. Martinez
- Department of Molecular Microbiology and Immunology, University of Texas at San Antonio, San Antonio, TX, USA
- South Texas Center for Emerging Infectious Diseases (STCEID), San Antonio, TX, USA
| | - Armando L. Rodriguez
- University of Texas at San Antonio, Research Computing Support Group, San Antonio, TX, USA
| | - Joseph M. Bosilevac
- U.S. Department of Agriculture (USDA), Agricultural Research Service (ARS), Roman L. Hruska U.S. Meat Animal Research Center, Clay Center, NE, USA
| | - Peter Feng†
- U.S. Food and Drug Administration (FDA), College Park, MD, USA
| | - Mark Eppinger
- Department of Molecular Microbiology and Immunology, University of Texas at San Antonio, San Antonio, TX, USA
- South Texas Center for Emerging Infectious Diseases (STCEID), San Antonio, TX, USA
- *Correspondence: Mark Eppinger,
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Serek P, Oleksy-Wawrzyniak M. The Effect of Bacterial Infections, Probiotics and Zonulin on Intestinal Barrier Integrity. Int J Mol Sci 2021; 22:11359. [PMID: 34768787 PMCID: PMC8583036 DOI: 10.3390/ijms222111359] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2021] [Revised: 10/15/2021] [Accepted: 10/19/2021] [Indexed: 12/12/2022] Open
Abstract
The intestinal barrier plays an extremely important role in maintaining the immune homeostasis of the gut and the entire body. It is made up of an intricate system of cells, mucus and intestinal microbiota. A complex system of proteins allows the selective permeability of elements that are safe and necessary for the proper nutrition of the body. Disturbances in the tightness of this barrier result in the penetration of toxins and other harmful antigens into the system. Such events lead to various digestive tract dysfunctions, systemic infections, food intolerances and autoimmune diseases. Pathogenic and probiotic bacteria, and the compounds they secrete, undoubtedly affect the properties of the intestinal barrier. The discovery of zonulin, a protein with tight junction regulatory activity in the epithelia, sheds new light on the understanding of the role of the gut barrier in promoting health, as well as the formation of diseases. Coincidentally, there is an increasing number of reports on treatment methods that target gut microbiota, which suggests that the prevention of gut-barrier defects may be a viable approach for improving the condition of COVID-19 patients. Various bacteria-intestinal barrier interactions are the subject of this review, aiming to show the current state of knowledge on this topic and its potential therapeutic applications.
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Affiliation(s)
- Paweł Serek
- Department of Biochemistry and Immunochemistry, Wroclaw Medical University, 50-368 Wroclaw, Poland
| | - Monika Oleksy-Wawrzyniak
- Department of Pharmaceutical Microbiology and Parasitology, Wroclaw Medical University, 50-556 Wroclaw, Poland;
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Pakbin B, Brück WM, Rossen JWA. Virulence Factors of Enteric Pathogenic Escherichia coli: A Review. Int J Mol Sci 2021; 22:9922. [PMID: 34576083 PMCID: PMC8468683 DOI: 10.3390/ijms22189922] [Citation(s) in RCA: 51] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2021] [Revised: 09/09/2021] [Accepted: 09/12/2021] [Indexed: 12/18/2022] Open
Abstract
Escherichia coli are remarkably versatile microorganisms and important members of the normal intestinal microbiota of humans and animals. This harmless commensal organism can acquire a mixture of comprehensive mobile genetic elements that contain genes encoding virulence factors, becoming an emerging human pathogen capable of causing a broad spectrum of intestinal and extraintestinal diseases. Nine definite enteric E. coli pathotypes have been well characterized, causing diseases ranging from various gastrointestinal disorders to urinary tract infections. These pathotypes employ many virulence factors and effectors subverting the functions of host cells to mediate their virulence and pathogenesis. This review summarizes new developments in our understanding of diverse virulence factors associated with encoding genes used by different pathotypes of enteric pathogenic E. coli to cause intestinal and extraintestinal diseases in humans.
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Affiliation(s)
- Babak Pakbin
- Institute for Life Technologies, University of Applied Sciences Western Switzerland Valais-Wallis, 1950 Sion 2, Switzerland;
- Department of Medical Microbiology and Infection Prevention, University Medical Center Groningen, University of Groningen, 9713 GZ Groningen, The Netherlands;
- Medical Microbiology Research Center, Qazvin University of Medical Sciences, Qazvin 15315-3419, Iran
| | - Wolfram M. Brück
- Institute for Life Technologies, University of Applied Sciences Western Switzerland Valais-Wallis, 1950 Sion 2, Switzerland;
| | - John W. A. Rossen
- Department of Medical Microbiology and Infection Prevention, University Medical Center Groningen, University of Groningen, 9713 GZ Groningen, The Netherlands;
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Gadishaw-Lue C, Banaag A, Birstonas S, Francis AS, Barnett Foster D. Bile Salts Differentially Enhance Resistance of Enterohemorrhagic Escherichia coli O157:H7 to Host Defense Peptides. Infect Immun 2021; 89:e00719-20. [PMID: 33229368 PMCID: PMC7822141 DOI: 10.1128/iai.00719-20] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Accepted: 11/13/2020] [Indexed: 12/28/2022] Open
Abstract
During passage through the human gastrointestinal tract, enterohemorrhagic Escherichia coli (EHEC) is exposed to membrane-damaging bile in the small intestine. We previously reported that EHEC treatment with a physiological bile salt mixture upregulates basRS, encoding a two-component system, and arnBCADTEF, encoding the aminoarabinose lipid A modification pathway (J. V. Kus, A. Gebremedhin, V. Dang, S. L. Tran, A. Serbanescu, and D. Barnett Foster, J Bacteriol 193: 4509-4515, 2011, https://doi.org/10.1128/JB.00200-11). The present study examined the effect of bile salt mix (BSM) treatment on EHEC resistance to three human gastrointestinal defense peptides-HD-5, HNP-1, and LL-37-as well as the role of basRS and arnT in the respective responses. After BSM treatment, EHEC resistance to HD-5 and HNP-1 was significantly increased in a BSM-, defensin dose-dependent manner. The resistance phenotype was dependent on both basRS and arnT However, the BSM treatment did not alter EHEC resistance to LL-37, even when the ompT gene, encoding an LL-37 cleavage protease, was disrupted. Interestingly, enteropathogenic E. coli, a related pathogen that infects the small intestine, showed a similar BSM-induced resistance phenotype. Using a model of EHEC infection in Galleria mellonella, we found significantly lower survival rates in wax moth larvae infected with BSM-treated wild-type EHEC than in those infected with a BSM-treated basS mutant, suggesting that treatment with a physiological BSM enhances virulence through a basS-mediated pathway. The results of this investigation provide persuasive evidence that bile salts typically encountered during transit through the small intestine can serve as an environmental cue for EHEC, enhancing resistance to several key host defense peptides.
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Affiliation(s)
- Crystal Gadishaw-Lue
- Department of Chemistry and Biology, Ryerson University, Toronto, Ontario, Canada
| | - Alyssa Banaag
- Department of Chemistry and Biology, Ryerson University, Toronto, Ontario, Canada
| | - Sarah Birstonas
- Department of Chemistry and Biology, Ryerson University, Toronto, Ontario, Canada
| | - Aju-Sue Francis
- Department of Chemistry and Biology, Ryerson University, Toronto, Ontario, Canada
| | - Debora Barnett Foster
- Department of Chemistry and Biology, Ryerson University, Toronto, Ontario, Canada
- Faculty of Dentistry, University of Toronto, Toronto, Ontario, Canada
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Warr AR, Giorgio RT, Waldor MK. Genetic analysis of the role of the conserved inner membrane protein CvpA in EHEC resistance to deoxycholate. J Bacteriol 2020; 203:JB.00661-20. [PMID: 33361192 PMCID: PMC8095453 DOI: 10.1128/jb.00661-20] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2020] [Accepted: 12/15/2020] [Indexed: 12/23/2022] Open
Abstract
The function of cvpA, a bacterial gene predicted to encode an inner membrane protein, is largely unknown. Early studies in E. coli linked cvpA to Colicin V secretion and recent work revealed that it is required for robust intestinal colonization by diverse enteric pathogens. In enterohemorrhagic E. coli (EHEC), cvpA is required for resistance to the bile salt deoxycholate (DOC). Here, we carried out genome-scale transposon-insertion mutagenesis and spontaneous suppressor analysis to uncover cvpA's genetic interactions and identify common pathways that rescue the sensitivity of a ΔcvpA EHEC mutant to DOC. These screens demonstrated that mutations predicted to activate the σE-mediated extracytoplasmic stress response bypass the ΔcvpA mutant's susceptibility to DOC. Consistent with this idea, we found that deletions in rseA and msbB and direct overexpression of rpoE restored DOC resistance to the ΔcvpA mutant. Analysis of the distribution of CvpA homologs revealed that this inner membrane protein is conserved across diverse bacterial phyla, in both enteric and non-enteric bacteria that are not exposed to bile. Together, our findings suggest that CvpA plays a role in cell envelope homeostasis in response to DOC and similar stress stimuli in diverse bacterial species.IMPORTANCE Several enteric pathogens, including Enterohemorrhagic E. coli (EHEC), require CvpA to robustly colonize the intestine. This inner membrane protein is also important for secretion of a colicin and EHEC resistance to the bile salt deoxycholate (DOC), but its function is unknown. Genetic analyses carried out here showed that activation of the σE-mediated extracytoplasmic stress response restored the resistance of a cvpA mutant to DOC, suggesting that CvpA plays a role in cell envelope homeostasis. The conservation of CvpA across diverse bacterial phyla suggests that this membrane protein facilitates cell envelope homeostasis in response to varied cell envelope perturbations.
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Affiliation(s)
- Alyson R Warr
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts, USA
- Division of Infectious Disease, Brigham and Women's Hospital, Boston, Massachusetts, USA
| | - Rachel T Giorgio
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts, USA
| | - Matthew K Waldor
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts, USA
- Division of Infectious Disease, Brigham and Women's Hospital, Boston, Massachusetts, USA
- Howard Hughes Medical Institute, Boston, Massachusetts, USA
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Kunwar CB, Birstonas S, McPhee JB, Barnett Foster D. Molecular basis of bile-salt- and iron-induced enterohaemorrhagic E. coli resistance to cationic antimicrobial peptides. MICROBIOLOGY-SGM 2020; 166:1149-1159. [PMID: 33205745 DOI: 10.1099/mic.0.000988] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Colonization of the gastrointestinal tract by enterohaemorrhagic Escherichia coli (EHEC) is critically dependent on its ability to sense and respond to various microenvironments within the host. EHEC exposure to physiologically relevant levels of bile salts upregulates the two-component system, pmrAB, and the arnBCADTEF operon, resulting in lipopolysaccharide modification and increased resistance to the cationic antimicrobial peptide, polymyxin B (PMB). A similar pmrAB- and arn-dependent PMB resistance has been observed in Salmonella enterica in the presence of ferric iron. Limiting magnesium levels and mild acid can also induce Salmonella resistance to PMB through another two-component system, PhoPQ and the connector protein, PmrD. This study aims to evaluate the relative contributions of a bile-salt mix (BSM), iron, limiting magnesium as well as the roles of pmrAB, phoPQ and pmrD to EHEC's resistance to PMB. Killing assays show that EHEC treatment with the BSM or iron under excess magnesium and neutral pH conditions induces a pmrAB-dependent, phoP-independent PMB resistance. By contrast, exposure to limiting magnesium triggers a pmrB-, phoP- and pmrD-dependent PMB resistance. The iron-induced PMB resistance is independent of phoP and pmrD under limiting magnesium conditions while the bile-salt-induced PMB resistance is independent of pmrD only under non-PhoP-inducing conditions. GFP-pmrD transcriptional reporter studies reveal that the limiting magnesium enhances pmrD expression, which is repressed upon additional exposure to either BSM or iron. Our results also show that exposure to mild acid enhances PMB resistance in a pmrD-independent manner and GFP reporter results confirm minimal expression of pmrD at this pH regardless of the magnesium level. This study provides novel insights into how EHEC differentially employs PmrAB, PhoPQ and PmrD to monitor and respond to bile salts, iron, acidic pH and magnesium typically encountered within the gastrointestinal tract in order to modulate its survival against cationic antimicrobial peptides.
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Affiliation(s)
- Chhatra B Kunwar
- Department of Chemistry & Biology, Ryerson University, Toronto, ON, Canada
| | - Sarah Birstonas
- Department of Chemistry & Biology, Ryerson University, Toronto, ON, Canada
| | - Joseph B McPhee
- Department of Chemistry & Biology, Ryerson University, Toronto, ON, Canada
| | - Debora Barnett Foster
- Faculty of Dentistry, University of Toronto, Toronto, ON, Canada.,Department of Chemistry & Biology, Ryerson University, Toronto, ON, Canada
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Roussel C, De Paepe K, Galia W, De Bodt J, Chalancon S, Leriche F, Ballet N, Denis S, Alric M, Van de Wiele T, Blanquet-Diot S. Spatial and temporal modulation of enterotoxigenic E. coli H10407 pathogenesis and interplay with microbiota in human gut models. BMC Biol 2020; 18:141. [PMID: 33054775 PMCID: PMC7559199 DOI: 10.1186/s12915-020-00860-x] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Accepted: 08/31/2020] [Indexed: 01/09/2023] Open
Abstract
BACKGROUND Enterotoxigenic Escherichia coli (ETEC) substantially contributes to the burden of diarrheal illnesses in developing countries. With the use of complementary in vitro models of the human digestive environment, TNO gastrointestinal model (TIM-1), and Mucosal Simulator of the Human Intestinal Microbial Ecosystem (M-SHIME), we provided the first detailed report on the spatial-temporal modulation of ETEC H10407 survival, virulence, and its interplay with gut microbiota. These systems integrate the main physicochemical parameters of the human upper digestion (TIM-1) and simulate the ileum vs ascending colon microbial communities and luminal vs mucosal microenvironments, captured from six fecal donors (M-SHIME). RESULTS A loss of ETEC viability was noticed upon gastric digestion, while a growth renewal was found at the end of jejunal and ileal digestion. The remarkable ETEC mucosal attachment helped to maintain luminal concentrations above 6 log10 mL-1 in the ileum and ascending colon up to 5 days post-infection. Seven ETEC virulence genes were monitored. Most of them were switched on in the stomach and switched off in the TIM-1 ileal effluents and in a late post-infectious stage in the M-SHIME ascending colon. No heat-labile enterotoxin production was measured in the stomach in contrast to the ileum and ascending colon. Using 16S rRNA gene-based amplicon sequencing, ETEC infection modulated the microbial community structure of the ileum mucus and ascending colon lumen. CONCLUSIONS This study provides a better understanding of the interplay between ETEC and gastrointestinal cues and may serve to complete knowledge on ETEC pathogenesis and inspire novel prophylactic strategies for diarrheal diseases.
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Affiliation(s)
- Charlène Roussel
- Université Clermont Auvergne, UMR UCA-INRA 454 MEDIS, Microbiology Digestive Environment and Health, Clermont-Ferrand, France.,CMET, Center for Microbial Ecology and Technology, Department of Biotechnology, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium
| | - Kim De Paepe
- CMET, Center for Microbial Ecology and Technology, Department of Biotechnology, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium
| | - Wessam Galia
- UMR 5557 Microbial Ecology, Research Group on Bacterial Opportunistic Pathogens and Environment, CNRS, VetAgro Sup, Lyon, France
| | - Jana De Bodt
- CMET, Center for Microbial Ecology and Technology, Department of Biotechnology, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium
| | - Sandrine Chalancon
- Université Clermont Auvergne, UMR UCA-INRA 454 MEDIS, Microbiology Digestive Environment and Health, Clermont-Ferrand, France
| | | | - Nathalie Ballet
- Lesaffre International, Lesaffre Group, Marcq-en-Baroeul, France
| | - Sylvain Denis
- Université Clermont Auvergne, UMR UCA-INRA 454 MEDIS, Microbiology Digestive Environment and Health, Clermont-Ferrand, France
| | - Monique Alric
- Université Clermont Auvergne, UMR UCA-INRA 454 MEDIS, Microbiology Digestive Environment and Health, Clermont-Ferrand, France
| | - Tom Van de Wiele
- CMET, Center for Microbial Ecology and Technology, Department of Biotechnology, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium.
| | - Stéphanie Blanquet-Diot
- Université Clermont Auvergne, UMR UCA-INRA 454 MEDIS, Microbiology Digestive Environment and Health, Clermont-Ferrand, France.
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The Ethanolamine-Sensing Transcription Factor EutR Promotes Virulence and Transmission during Citrobacter rodentium Intestinal Infection. Infect Immun 2020; 88:IAI.00137-20. [PMID: 32631916 DOI: 10.1128/iai.00137-20] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2020] [Accepted: 06/26/2020] [Indexed: 12/18/2022] Open
Abstract
Enteric pathogens exploit chemical and nutrient signaling to gauge their location within a host and control expression of traits important for infection. Ethanolamine-containing molecules are essential in host physiology and play important roles in intestinal processes. The transcription factor EutR is conserved in the Enterobacteriaceae and is required for ethanolamine sensing and metabolism. In enterohemorrhagic Escherichia coli (EHEC) O157:H7, EutR responds to ethanolamine to activate expression of traits required for host colonization and disease; however, the importance of EutR to EHEC intestinal infection has not been examined. Because EHEC does not naturally colonize or cause disease in mice, we employed the natural murine pathogen Citrobacter rodentium as a model of EHEC virulence to investigate the importance of EutR in vivo EHEC and C. rodentium possess the locus of enterocyte effacement (LEE), which is the canonical virulence trait of attaching and effacing pathogens. Our findings demonstrate that ethanolamine sensing and EutR-dependent regulation of the LEE are conserved in C. rodentium Moreover, during infection, EutR is required for maximal LEE expression, colonization, and transmission efficiency. These findings reveal that EutR not only is important for persistence during the primary host infection cycle but also is required for maintenance in a host population.
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12
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Ohno H. The impact of metabolites derived from the gut microbiota on immune regulation and diseases. Int Immunol 2020; 32:629-636. [PMID: 32564086 DOI: 10.1093/intimm/dxaa041] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2020] [Accepted: 06/14/2020] [Indexed: 12/11/2022] Open
Abstract
The gut microbiota strongly impacts the physiology and pathology in the host. To understand the complex interactions between host and gut microbiota, an 'integrated omics' approach has been employed, where exhaustive analyses for the different layers of cellular functions, such as epigenomics, transcriptomics and metabolomics, in addition to metagenomics, are combined. With this approach, the mechanisms whereby short-chain fatty acids (SCFAs) regulate host defense and the immune system have been elucidated. In a gnotobiotic mouse model of enterohemorrhagic Escherichia coli infection, Bifidobacterium-derived acetate can protect from infection-mediated death by changing the gene expression profile of colonic epithelial cells. It has also been shown that gut microbiota-derived butyrate enhances colonic regulatory T-cell differentiation through its epigenetic modulatory ability via histone deacetylase inhibition. SCFAs are involved in many other immunomodulatory effects as well as host pathophysiological conditions. Dysbiosis in the gut has been implicated in the pathogenesis of many diseases. Although the causal relationship of gut microbial dysbiosis and/or metabolites with pathogenesis is mostly unknown, mechanistic insights have been elucidated in some cases. Metabolism in the gut microbiota and host liver produces trimethylamine N-oxide, which is known to aggravate atherosclerosis, and a secondary bile acid deoxycholate, which reportedly induces non-alcoholic steatohepatitis-related hepatocellular carcinoma. It has been reported that secondary bile acids could also induce the differentiation of peripherally derived regulatory T cells in the gut. Further studies on the interactions between the host and gut microbiota could lead to the development of new therapeutic strategies as well as in preventive medicine.
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Affiliation(s)
- Hiroshi Ohno
- Laboratory for Intestinal Ecosystem, RIKEN Center for Integrative Medical Sciences, Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa, Japan.,Intestinal Microbiota Project, Kanagawa Institute of Industrial Science and Technology, Sakado, Takatsu-ku, Kawasaki, Kanagawa 213-0012, Japan.,Immunobiology Laboratory, Graduate School of Medical Life Science, Yokohama City University, Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa, Japan.,Laboratory for Immune Regulation, Graduate School of Medicine, Chiba University, Inohana, Chuo-ku, Chiba, Japan
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13
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Liu B, Wang J, Wang L, Ding P, Yang P, Yang B. Transcriptional Activator OvrA Encoded in O Island 19 Modulates Virulence Gene Expression in Enterohemorrhagic Escherichia coli O157:H7. J Infect Dis 2020; 221:820-829. [PMID: 31630185 DOI: 10.1093/infdis/jiz458] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2019] [Accepted: 09/05/2019] [Indexed: 01/25/2023] Open
Abstract
The human intestinal pathogen enterohemorrhagic Escherichia coli (EHEC) O157:H7 causes bloody diarrhea, hemorrhagic colitis, and fatal hemolytic uremic syndrome. Its genome contains 177 unique O islands (OIs), which contribute largely to the high virulence and pathogenicity although most OI genes remain uncharacterized. In the current study, we demonstrated that OI-19 is required for EHEC O157:H7 adherence to host cells. Z0442 (OI-encoded virulence regulator A [OvrA]) encoded in OI-19 positively regulated bacterial adherence by activating locus of enterocyte effacement (LEE) gene expression through direct OvrA binding to the gene promoter region of the LEE gene master regulator Ler. Mouse colonization experiments revealed that OvrA promotes EHEC O157:H7 adherence in mouse intestine, preferentially the colon. Finally, OvrA also regulated virulence in other non-O157 pathogenic E. coli, including EHEC strains O145:H28 and O157:H16 and enteropathogenic E. coli strain O55:H7. Our work markedly enriches the understanding of bacterial adherence control and provides another example of laterally acquired regulators that mediate LEE gene expression.
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Affiliation(s)
- Bin Liu
- TEDA Institute of Biological Sciences and Biotechnology, Nankai University, TEDA, Tianjin, China.,The Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Tianjin, China
| | - Junyue Wang
- TEDA Institute of Biological Sciences and Biotechnology, Nankai University, TEDA, Tianjin, China.,The Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Tianjin, China
| | - Lu Wang
- TEDA Institute of Biological Sciences and Biotechnology, Nankai University, TEDA, Tianjin, China.,The Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Tianjin, China
| | - Peng Ding
- TEDA Institute of Biological Sciences and Biotechnology, Nankai University, TEDA, Tianjin, China.,The Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Tianjin, China
| | - Pan Yang
- TEDA Institute of Biological Sciences and Biotechnology, Nankai University, TEDA, Tianjin, China.,The Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Tianjin, China
| | - Bin Yang
- TEDA Institute of Biological Sciences and Biotechnology, Nankai University, TEDA, Tianjin, China.,The Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Tianjin, China
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14
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Byakika S, Mukisa IM, Mugabi R, Muyanja C. Antimicrobial Activity of Lactic Acid Bacteria Starters against Acid Tolerant, Antibiotic Resistant, and Potentially Virulent E. coli Isolated from a Fermented Sorghum-Millet Beverage. Int J Microbiol 2019; 2019:2013539. [PMID: 31933646 PMCID: PMC6942839 DOI: 10.1155/2019/2013539] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Revised: 10/11/2019] [Accepted: 11/30/2019] [Indexed: 12/11/2022] Open
Abstract
Bacterial contamination of fermented foods is a serious global food safety challenge that requires effective control strategies. This study characterized presumptive E. coli isolated from Obushera, a traditional fermented cereal beverage from Uganda. Thereafter, the antimicrobial effect of lactic acid bacteria (LAB) previously isolated from Obushera, against the E. coli, was examined. The presumptive E. coli was incubated in brain heart infusion broth (pH = 3.6) at 25°C for 48 h. The most acid-stable strains were clustered using (GTG)5 rep-PCR fingerprinting and identified using 16S rRNA sequencing. E. coli was screened for Shiga toxins (Stx 1 and Stx 2) and Intimin (eae) virulence genes as well as antibiotic resistance. The spot-on-the-lawn method was used to evaluate antimicrobial activity. Eighteen isolates were acid stable and are identified as E. coli, Shigella, and Lysinibacillus. The Stx 2 gene and antibiotic resistance were detected in some E. coli isolates. The LAB were antagonistic against the E. coli. Lactic acid bacteria from traditional fermented foods can be applied in food processing to inhibit pathogens. Obushera lactic acid bacteria could be used to improve the safety of fermented foods.
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Affiliation(s)
- Stellah Byakika
- Department of Food Technology and Nutrition, School of Food Technology Nutrition and Bioengineering, College of Agricultural and Environmental Sciences, Makerere University, P.O. Box 7062, Kampala, Uganda
| | - Ivan Muzira Mukisa
- Department of Food Technology and Nutrition, School of Food Technology Nutrition and Bioengineering, College of Agricultural and Environmental Sciences, Makerere University, P.O. Box 7062, Kampala, Uganda
| | - Robert Mugabi
- Department of Food Technology and Nutrition, School of Food Technology Nutrition and Bioengineering, College of Agricultural and Environmental Sciences, Makerere University, P.O. Box 7062, Kampala, Uganda
| | - Charles Muyanja
- Department of Food Technology and Nutrition, School of Food Technology Nutrition and Bioengineering, College of Agricultural and Environmental Sciences, Makerere University, P.O. Box 7062, Kampala, Uganda
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15
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Warr AR, Hubbard TP, Munera D, Blondel CJ, Abel zur Wiesch P, Abel S, Wang X, Davis BM, Waldor MK. Transposon-insertion sequencing screens unveil requirements for EHEC growth and intestinal colonization. PLoS Pathog 2019; 15:e1007652. [PMID: 31404118 PMCID: PMC6705877 DOI: 10.1371/journal.ppat.1007652] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Revised: 08/22/2019] [Accepted: 08/01/2019] [Indexed: 12/28/2022] Open
Abstract
Enterohemorrhagic Escherichia coli O157:H7 (EHEC) is an important food-borne pathogen that colonizes the colon. Transposon-insertion sequencing (TIS) was used to identify genes required for EHEC and E. coli K-12 growth in vitro and for EHEC growth in vivo in the infant rabbit colon. Surprisingly, many conserved loci contribute to EHEC's but not to K-12's growth in vitro. There was a restrictive bottleneck for EHEC colonization of the rabbit colon, which complicated identification of EHEC genes facilitating growth in vivo. Both a refined version of an existing analytic framework as well as PCA-based analysis were used to compensate for the effects of the infection bottleneck. These analyses confirmed that the EHEC LEE-encoded type III secretion apparatus is required for growth in vivo and revealed that only a few effectors are critical for in vivo fitness. Over 200 mutants not previously associated with EHEC survival/growth in vivo also appeared attenuated in vivo, and a subset of these putative in vivo fitness factors were validated. Some were found to contribute to efficient type-three secretion while others, including tatABC, oxyR, envC, acrAB, and cvpA, promote EHEC resistance to host-derived stresses. cvpA is also required for intestinal growth of several other enteric pathogens, and proved to be required for EHEC, Vibrio cholerae and Vibrio parahaemolyticus resistance to the bile salt deoxycholate, highlighting the important role of this previously uncharacterized protein in pathogen survival. Collectively, our findings provide a comprehensive framework for understanding EHEC growth in the intestine.
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Affiliation(s)
- Alyson R. Warr
- Division of Infectious Diseases, Brigham & Women’s Hospital, Boston, Massachusetts, United States of America
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Troy P. Hubbard
- Division of Infectious Diseases, Brigham & Women’s Hospital, Boston, Massachusetts, United States of America
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Diana Munera
- Division of Infectious Diseases, Brigham & Women’s Hospital, Boston, Massachusetts, United States of America
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Carlos J. Blondel
- Division of Infectious Diseases, Brigham & Women’s Hospital, Boston, Massachusetts, United States of America
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Pia Abel zur Wiesch
- Division of Infectious Diseases, Brigham & Women’s Hospital, Boston, Massachusetts, United States of America
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Sören Abel
- Division of Infectious Diseases, Brigham & Women’s Hospital, Boston, Massachusetts, United States of America
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Xiaoxue Wang
- Division of Infectious Diseases, Brigham & Women’s Hospital, Boston, Massachusetts, United States of America
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Brigid M. Davis
- Division of Infectious Diseases, Brigham & Women’s Hospital, Boston, Massachusetts, United States of America
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Matthew K. Waldor
- Division of Infectious Diseases, Brigham & Women’s Hospital, Boston, Massachusetts, United States of America
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts, United States of America
- HHMI, Boston, Massachusetts, United States of America
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16
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The Escherichia coli O157:H7 carbon starvation-inducible lipoprotein Slp contributes to initial adherence in vitro via the human polymeric immunoglobulin receptor. PLoS One 2019; 14:e0216791. [PMID: 31188867 PMCID: PMC6561548 DOI: 10.1371/journal.pone.0216791] [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: 10/10/2018] [Accepted: 04/29/2019] [Indexed: 01/19/2023] Open
Abstract
Escherichia coli O157:H7 is the most well-studied serotype of the enterohemorrhagic E. coli (EHEC) class of E. coli intestinal pathogens and is responsible for many outbreaks of serious food-borne illness worldwide each year. Adherence mechanisms are a critical component of its pathogenesis, persistence in natural reservoirs, and environmental contamination. E. coli O157:H7 has a highly effective virulence operon, the Locus of Enterocyte Effacement (LEE), and its encoded intimate adherence mechanism is well characterized. However, factors involved in the preceding initial attachment are not well understood. In this study, we propose a mechanism of initial adherence used by E. coli O157:H7 in vitro. We describe a bacterial protein not previously reported to be involved in adherence, Slp, and its interactions with the human host protein polymeric immunoglobulin receptor (pIgR). The human pIgR has previously been shown to act as an adherence receptor for some mucosal pathogens and is highly expressed in the intestine. Following observation of significant colocalization between E. coli O157:H7 bacteria and pIgR location on Caco-2 cells, a co-immunoprecipitation (Co-IP) assay using a human recombinant Fc-tagged pIgR protein led to the identification of this protein. Disruption of Slp expression in E. coli O157:H7, through deletion of its encoding gene slp, produced a significant adherence deficiency to Caco-2 cells at early time points associated with initial adherence. Plasmid complementation of the slp gene fully restored the wild-type phenotype. Furthermore, immunofluorescence microscopy revealed evidence that this interaction is specific to the pathogenic strains of E. coli tested and not the nonpathogenic control strain E. coli K12. Additionally, deletion of slp gene resulted in the absence of the corresponding protein band in further Co-IP assays, while the plasmid-encoded slp gene complementation of the deletion mutant strain restored the wild-type pattern. These data support the proposal that Slp directly contributes to initial adherence, with the pIgR protein as its proposed receptor.
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17
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Ellis SJ, Yasir M, Browning DF, Busby SJW, Schüller S. Oxygen and contact with human intestinal epithelium independently stimulate virulence gene expression in enteroaggregative Escherichia coli. Cell Microbiol 2019; 21:e13012. [PMID: 30673154 PMCID: PMC6563437 DOI: 10.1111/cmi.13012] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2018] [Revised: 12/14/2018] [Accepted: 01/14/2019] [Indexed: 12/22/2022]
Abstract
Enteroaggregative Escherichia coli (EAEC) are important intestinal pathogens causing acute and persistent diarrhoeal illness worldwide. Although many putative EAEC virulence factors have been identified, their association with pathogenesis remains unclear. As environmental cues can modulate bacterial virulence, we investigated the effect of oxygen and human intestinal epithelium on EAEC virulence gene expression to determine the involvement of respective gene products in intestinal colonisation and pathogenesis. Using in vitro organ culture of human intestinal biopsies, we established the colonic epithelium as the major colonisation site of EAEC strains 042 and 17‐2. We subsequently optimised a vertical diffusion chamber system with polarised T84 colon carcinoma cells for EAEC infection and showed that oxygen induced expression of the global regulator AggR, aggregative adherence fimbriae, E. coli common pilus, EAST‐1 toxin, and dispersin in EAEC strain 042 but not in 17‐2. Furthermore, the presence of T84 epithelia stimulated additional expression of the mucinase Pic and the toxins HlyE and Pet. This induction was dependent on physical host cell contact and did not require AggR. Overall, these findings suggest that EAEC virulence in the human gut is modulated by environmental signals including oxygen and the intestinal epithelium.
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Affiliation(s)
- Samuel J Ellis
- Norwich Medical School, University of East Anglia, Norwich, UK.,Quadram Institute Bioscience, Norwich, UK
| | - Muhammad Yasir
- Quadram Institute Bioscience, Norwich, UK.,Institute of Microbiology and Infection, University of Birmingham, Birmingham, UK
| | - Douglas F Browning
- Institute of Microbiology and Infection, University of Birmingham, Birmingham, UK
| | - Stephen J W Busby
- Institute of Microbiology and Infection, University of Birmingham, Birmingham, UK
| | - Stephanie Schüller
- Norwich Medical School, University of East Anglia, Norwich, UK.,Quadram Institute Bioscience, Norwich, UK
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18
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Modulation of Enterohaemorrhagic Escherichia coli Survival and Virulence in the Human Gastrointestinal Tract. Microorganisms 2018; 6:microorganisms6040115. [PMID: 30463258 PMCID: PMC6313751 DOI: 10.3390/microorganisms6040115] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2018] [Revised: 11/16/2018] [Accepted: 11/18/2018] [Indexed: 01/05/2023] Open
Abstract
Enterohaemorrhagic Escherichia coli (EHEC) is a major foodborne pathogen responsible for human diseases ranging from diarrhoea to life-threatening complications. Survival of the pathogen and modulation of virulence gene expression along the human gastrointestinal tract (GIT) are key features in bacterial pathogenesis, but remain poorly described, due to a paucity of relevant model systems. This review will provide an overview of the in vitro and in vivo studies investigating the effect of abiotic (e.g., gastric acid, bile, low oxygen concentration or fluid shear) and biotic (e.g., gut microbiota, short chain fatty acids or host hormones) parameters of the human gut on EHEC survival and/or virulence (especially in relation with motility, adhesion and toxin production). Despite their relevance, these studies display important limitations considering the complexity of the human digestive environment. These include the evaluation of only one single digestive parameter at a time, lack of dynamic flux and compartmentalization, and the absence of a complex human gut microbiota. In a last part of the review, we will discuss how dynamic multi-compartmental in vitro models of the human gut represent a novel platform for elucidating spatial and temporal modulation of EHEC survival and virulence along the GIT, and provide new insights into EHEC pathogenesis.
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19
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De-O-Acetylation of mucin-derived sialic acids by recombinant NanS-p esterases of Escherichia coli O157:H7 strain EDL933. Int J Med Microbiol 2018; 308:1113-1120. [PMID: 30340996 PMCID: PMC7106450 DOI: 10.1016/j.ijmm.2018.10.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2018] [Revised: 09/27/2018] [Accepted: 10/05/2018] [Indexed: 01/11/2023] Open
Abstract
Enterohemorrhagic Escherichia coli (EHEC) O157:H7 strain EDL933 encodes the single chromosomal 9-O-acetylesterase NanS, and several copies of prophage-encoded 9-O-acetylesterases (NanS-p). These enzymes have recently been shown to cleave 5-N-acetyl-9-O-acetyl neuraminic acid (Neu5,9Ac2) to yield de-O-acetylated Neu5Ac, the latter of which may serve as a carbon and/or nitrogen source. In the current study, we investigated the NanS- and NanS-p-mediated digestion of synthetic O-acetylated neuraminic acids and bovine submaxillary glands mucin (BSM)-derived O-acetylneuraminic acids by high-performance thin-layer chromatography (HPTLC) and nano electrospray ionization mass spectrometry (nanoESI MS). Initial HPTLC analyses showed the expected activity of NanS and NanS-p variants for Neu5,9Ac2. However, all tested enzymes were unable to de-O-acetylate 5-N-acetyl-4-O-acetylneuraminic acid (Neu5,4 Ac2) in our test system. The nanoESI MS analysis of neuraminic acids after treatment of BSM with NanS-p gave evidence that NanS-p variants of EHEC O157:H7 strain EDL933 cleave off O-acetyl groups from mono-, di-, and tri-O-acetylated Neu5Ac and N-glycolylneuraminic acid (Neu5Gc), regardless of the carbon positions C7, C8 or C9 of the acetate esters. This enzyme activity leads to neuraminidase-accessible Neu5Ac and Neu5Gc on mucin glycans. Moreover, we could demonstrate by HPTLC analyses that recombinant Bacteroides thetaiotaomicron sialidase (BTSA-His) was able to cleave Neu5Ac and Neu5,9Ac2 from BSM and that the combination of BTSA-His with both NanS-His and NanS-p-His derivatives enhanced the release of de-O-acetylated core Neu5Ac and Neu5Gc from mammalian mucin O-glycans. Growth experiments with EHEC wildtype strain EDL933, its nanS and nanS/nanS-p1a-p7 mutant and exogenous BTSA-His in BSM demonstrated that the presence of BTSA-His enhanced growth of EDL933 and the nanS deletion mutant but not the nanS/nanS-p1a-p7 mutant. Thus, we hypothesize that the expression of sialic acid O-acetylesterases with a broad specificity could be an advantage in competition with the gut microbiota for nutrients and facilitate EHEC colonization in the human large intestine.
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20
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Ethanolamine Influences Human Commensal Escherichia coli Growth, Gene Expression, and Competition with Enterohemorrhagic E. coli O157:H7. mBio 2018; 9:mBio.01429-18. [PMID: 30279284 PMCID: PMC6168858 DOI: 10.1128/mbio.01429-18] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The microbiota protects the host from invading pathogens by limiting access to nutrients. In turn, bacterial pathogens selectively exploit metabolites not readily used by the microbiota to establish infection. Ethanolamine has been linked to pathogenesis of diverse pathogens by serving as a noncompetitive metabolite that enhances pathogen growth as well as a signal that modulates virulence. Although ethanolamine is abundant in the gastrointestinal tract, the prevailing idea is that commensal bacteria do not utilize EA, and thus, EA utilization has been particularly associated with pathogenesis. Here, we provide evidence that two human commensal Escherichia coli isolates readily utilize ethanolamine to enhance growth, modulate gene expression, and outgrow the pathogen enterohemorrhagic E. coli. These data indicate a more complex role for ethanolamine in host-microbiota-pathogen interactions. A core principle of bacterial pathogenesis is that pathogens preferentially utilize metabolites that commensal bacteria do not in order to sidestep nutritional competition. The metabolite ethanolamine (EA) is well recognized to play a central role in host adaptation for diverse pathogens. EA promotes growth and influences virulence during host infection. Although genes encoding EA utilization have been identified in diverse bacteria (nonpathogenic and pathogenic), a prevailing idea is that commensal bacteria do not utilize EA to enhance growth, and thus, EA is a noncompetitive metabolite for pathogens. Here, we show that EA augments growth of two human commensal strains of Escherichia coli. Significantly, these commensal strains grow more rapidly than, and even outcompete, the pathogen enterohemorrhagic E. coli O157:H7 specifically when EA is provided as the sole nitrogen source. Moreover, EA-dependent signaling is similarly conserved in the human commensal E. coli strain HS and influences expression of adhesins. These findings suggest a more extensive role for EA utilization in bacterial physiology and host-microbiota-pathogen interactions than previously appreciated.
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21
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After the Fact(or): Posttranscriptional Gene Regulation in Enterohemorrhagic Escherichia coli O157:H7. J Bacteriol 2018; 200:JB.00228-18. [PMID: 29967119 DOI: 10.1128/jb.00228-18] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
To adapt to ever-changing environments, pathogens quickly alter gene expression. This can occur through transcriptional, posttranscriptional, or posttranslational regulation. Historically, transcriptional regulation has been thoroughly studied to understand pathogen niche adaptation, whereas posttranscriptional and posttranslational gene regulation has only relatively recently been appreciated to play a central role in bacterial pathogenesis. Posttranscriptional regulation may involve chaperones, nucleases, and/or noncoding small RNAs (sRNAs) and typically controls gene expression by altering the stability and/or translation of the target mRNA. In this review, we highlight the global importance of posttranscriptional regulation to enterohemorrhagic Escherichia coli (EHEC) gene expression and discuss specific mechanisms of how EHEC regulates expression of virulence factors critical to host colonization and disease progression. The low infectious dose of this intestinal pathogen suggests that EHEC is particularly well adapted to respond to the host environment.
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22
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Horn N, Bhunia AK. Food-Associated Stress Primes Foodborne Pathogens for the Gastrointestinal Phase of Infection. Front Microbiol 2018; 9:1962. [PMID: 30190712 PMCID: PMC6115488 DOI: 10.3389/fmicb.2018.01962] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2018] [Accepted: 08/02/2018] [Indexed: 12/13/2022] Open
Abstract
The incidence of foodborne outbreaks and product recalls is on the rise. The ability of the pathogen to adapt and survive under stressful environments of food processing and the host gastrointestinal tract may contribute to increasing foodborne illnesses. In the host, multiple factors such as bacteriolytic enzymes, acidic pH, bile, resident microflora, antimicrobial peptides, and innate and adaptive immune responses are essential in eliminating pathogens. Likewise, food processing and preservation techniques are employed to eliminate or reduce human pathogens load in food. However, sub-lethal processing or preservation treatments may evoke bacterial coping mechanisms that alter gene expression, specifically and broadly, resulting in resistance to the bactericidal insults. Furthermore, environmentally cued changes in gene expression can lead to changes in bacterial adhesion, colonization, invasion, and toxin production that contribute to pathogen virulence. The shared microenvironment between the food preservation techniques and the host gastrointestinal tract drives microbes to adapt to the stressful environment, resulting in enhanced virulence and infectivity during a foodborne illness episode.
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Affiliation(s)
- Nathan Horn
- Department of Animal Sciences, Purdue University, West Lafayette, IN, United States
| | - Arun K. Bhunia
- Molecular Food Microbiology Laboratory, Department of Food Science, Purdue University, West Lafayette, IN, United States
- Department of Comparative Pathobiology, Purdue University, West Lafayette, IN, United States
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23
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Kuo CJ, Wang ST, Lin CM, Chiu HC, Huang CR, Lee DY, Chang GD, Chou TC, Chen JW, Chen CS. A multi-omic analysis reveals the role of fumarate in regulating the virulence of enterohemorrhagic Escherichia coli. Cell Death Dis 2018. [PMID: 29515100 PMCID: PMC5841434 DOI: 10.1038/s41419-018-0423-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The enteric pathogen enterohemorrhagic Escherichia coli (EHEC) is responsible for outbreaks of bloody diarrhea and hemolytic uremic syndrome (HUS) worldwide. Several molecular mechanisms have been described for the pathogenicity of EHEC; however, the role of bacterial metabolism in the virulence of EHEC during infection in vivo remains unclear. Here we show that aerobic metabolism plays an important role in the regulation of EHEC virulence in Caenorhabditis elegans. Our functional genomic analyses showed that disruption of the genes encoding the succinate dehydrogenase complex (Sdh) of EHEC, including the sdhA gene, attenuated its toxicity toward C. elegans animals. Sdh converts succinate to fumarate and links the tricarboxylic acid (TCA) cycle and the electron transport chain (ETC) simultaneously. Succinate accumulation and fumarate depletion in the EHEC sdhA mutant cells were also demonstrated to be concomitant by metabolomic analyses. Moreover, fumarate replenishment to the sdhA mutant significantly increased its virulence toward C. elegans. These results suggest that the TCA cycle, ETC, and alteration in metabolome all account for the attenuated toxicity of the sdhA mutant, and Sdh catabolite fumarate in particular plays a critical role in the regulation of EHEC virulence. In addition, we identified the tryptophanase (TnaA) as a downstream virulence determinant of SdhA using a label-free proteomic method. We demonstrated that expression of tnaA is regulated by fumarate in EHEC. Taken together, our multi-omic analyses demonstrate that sdhA is required for the virulence of EHEC, and aerobic metabolism plays important roles in the pathogenicity of EHEC infection in C. elegans. Moreover, our study highlights the potential targeting of SdhA, if druggable, as alternative preventive or therapeutic strategies by which to combat EHEC infection.
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Affiliation(s)
- Cheng-Ju Kuo
- Department of Biochemistry and Molecular Biology, College of Medicine, National Cheng Kung University, Tainan, Taiwan.,Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Sin-Tian Wang
- Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Chia-Mei Lin
- Department of Biochemistry and Molecular Biology, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Hao-Chieh Chiu
- Department of Clinical Laboratory Sciences and Medical Biotechnology, National Taiwan University, Taipei, Taiwan
| | - Cheng-Rung Huang
- Department of Biochemistry and Molecular Biology, College of Medicine, National Cheng Kung University, Tainan, Taiwan.,Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Der-Yen Lee
- The Graduate Institute of Integrated Medicine, China Medical University, Taichung, Taiwan.,Graduate Institute of Biochemical Sciences, Technology Commons, Center for Systems Biology, National Taiwan University, Taipei, Taiwan
| | - Geen-Dong Chang
- Graduate Institute of Biochemical Sciences, Technology Commons, Center for Systems Biology, National Taiwan University, Taipei, Taiwan
| | - Ting-Chen Chou
- Department of Biochemistry and Molecular Biology, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Jenn-Wei Chen
- Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan, Taiwan. .,Department of Microbiology and Immunology, College of Medicine, National Cheng Kung University, Tainan, Taiwan.
| | - Chang-Shi Chen
- Department of Biochemistry and Molecular Biology, College of Medicine, National Cheng Kung University, Tainan, Taiwan. .,Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan, Taiwan.
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24
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Abstract
Enteric pathogens with low infectious doses rely on the ability to orchestrate the expression of virulence and metabolism-associated genes in response to environmental cues for successful infection. Accordingly, the human pathogen enterohemorrhagic Escherichia coli (EHEC) employs a complex multifaceted regulatory network to link the expression of type III secretion system (T3SS) components to nutrient availability. While phosphorylation of histidine and aspartate residues on two-component system response regulators is recognized as an integral part of bacterial signaling, the involvement of phosphotyrosine-mediated control is minimally explored in Gram-negative pathogens. Our recent phosphotyrosine profiling study of E. coli identified 342 phosphorylated proteins, indicating that phosphotyrosine modifications in bacteria are more prevalent than previously anticipated. The present study demonstrates that tyrosine phosphorylation of a metabolite-responsive LacI/GalR family regulator, Cra, negatively affects T3SS expression under glycolytic conditions that are typical for the colonic lumen environment where production of the T3SS is unnecessary. Our data suggest that Cra phosphorylation affects T3SS expression by modulating the expression of ler, which encodes the major activator of EHEC virulence gene expression. Phosphorylation of the Cra Y47 residue diminishes DNA binding to fine-tune the expression of virulence-associated genes, including those of the locus of enterocyte effacement pathogenicity island that encode the T3SS, and thereby negatively affects the formation of attaching and effacing lesions. Our data indicate that tyrosine phosphorylation provides an additional mechanism to control the DNA binding of Cra and other LacI/GalR family regulators, including LacI and PurR. This study describes an initial effort to unravel the role of global phosphotyrosine signaling in the control of EHEC virulence potential. Enterohemorrhagic Escherichia coli (EHEC) causes outbreaks of hemorrhagic colitis and the potentially fatal hemolytic-uremic syndrome. Successful host colonization by EHEC relies on the ability to coordinate the expression of virulence factors in response to environmental cues. A complex network that integrates environmental signals at multiple regulatory levels tightly controls virulence gene expression. We demonstrate that EHEC utilizes a previously uncharacterized phosphotyrosine signaling pathway through Cra to fine-tune the expression of virulence-associated genes to effectively control T3SS production. This study demonstrates that tyrosine phosphorylation negatively affects the DNA-binding capacity of Cra, which affects the expression of genes related to virulence and metabolism. We demonstrate for the first time that phosphotyrosine-mediated control affects global transcription in EHEC. Our data provide insight into a hitherto unexplored regulatory level of the global network controlling EHEC virulence gene expression.
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van der Hoven C, Ubomba-Jaswa E, van der Merwe B, Loubser M, Abia ALK. The impact of various land uses on the microbial and physicochemical quality of surface water bodies in developing countries: Prioritisation of water resources management areas. ACTA ACUST UNITED AC 2017. [DOI: 10.1016/j.enmm.2017.10.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Survival of the Fittest: How Bacterial Pathogens Utilize Bile To Enhance Infection. Clin Microbiol Rev 2017; 29:819-36. [PMID: 27464994 DOI: 10.1128/cmr.00031-16] [Citation(s) in RCA: 68] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Bacterial pathogens have coevolved with humans in order to efficiently infect, replicate within, and be transmitted to new hosts to ensure survival and a continual infection cycle. For enteric pathogens, the ability to adapt to numerous host factors under the harsh conditions of the gastrointestinal tract is critical for establishing infection. One such host factor readily encountered by enteric bacteria is bile, an innately antimicrobial detergent-like compound essential for digestion and nutrient absorption. Not only have enteric pathogens evolved to resist the bactericidal conditions of bile, but these bacteria also utilize bile as a signal to enhance virulence regulation for efficient infection. This review provides a comprehensive and up-to-date analysis of bile-related research with enteric pathogens. From common responses to the unique expression of specific virulence factors, each pathogen has overcome significant challenges to establish infection in the gastrointestinal tract. Utilization of bile as a signal to modulate virulence factor expression has led to important insights for our understanding of virulence mechanisms for many pathogens. Further research on enteric pathogens exposed to this in vivo signal will benefit therapeutic and vaccine development and ultimately enhance our success at combating such elite pathogens.
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Geue L, Menge C, Eichhorn I, Semmler T, Wieler LH, Pickard D, Berens C, Barth SA. Evidence for Contemporary Switching of the O-Antigen Gene Cluster between Shiga Toxin-Producing Escherichia coli Strains Colonizing Cattle. Front Microbiol 2017; 8:424. [PMID: 28377748 PMCID: PMC5359238 DOI: 10.3389/fmicb.2017.00424] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2017] [Accepted: 02/28/2017] [Indexed: 11/13/2022] Open
Abstract
Shiga toxin-producing Escherichia coli (STEC) comprise a group of zoonotic enteric pathogens with ruminants, especially cattle, as the main reservoir. O-antigens are instrumental for host colonization and bacterial niche adaptation. They are highly immunogenic and, therefore, targeted by the adaptive immune system. The O-antigen is one of the most diverse bacterial cell constituents and variation not only exists between different bacterial species, but also between individual isolates/strains within a single species. We recently identified STEC persistently infecting cattle and belonging to the different serotypes O156:H25 (n = 21) and O182:H25 (n = 15) that were of the MLST sequence types ST300 or ST688. These STs differ by a single nucleotide in purA only. Fitness-, virulence-associated genome regions, and CRISPR/CAS (clustered regularly interspaced short palindromic repeats/CRISPR associated sequence) arrays of these STEC O156:H25 and O182:H25 isolates were highly similar, and identical genomic integration sites for the stx converting bacteriophages and the core LEE, identical Shiga toxin converting bacteriophage genes for stx1a, identical complete LEE loci, and identical sets of chemotaxis and flagellar genes were identified. In contrast to this genomic similarity, the nucleotide sequences of the O-antigen gene cluster (O-AGC) regions between galF and gnd and very few flanking genes differed fundamentally and were specific for the respective serotype. Sporadic aEPEC O156:H8 isolates (n = 5) were isolated in temporal and spatial proximity. While the O-AGC and the corresponding 5' and 3' flanking regions of these aEPEC isolates were identical to the respective region in the STEC O156:H25 isolates, the core genome, the virulence associated genome regions and the CRISPR/CAS elements differed profoundly. Our cumulative epidemiological and molecular data suggests a recent switch of the O-AGC between isolates with O156:H8 strains having served as DNA donors. Such O-antigen switches can affect the evaluation of a strain's pathogenic and virulence potential, suggesting that NGS methods might lead to a more reliable risk assessment.
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Affiliation(s)
- Lutz Geue
- Friedrich-Loeffler-Institut/Federal Research Institute for Animal Health, Institute of Molecular PathogenesisJena, Germany
| | - Christian Menge
- Friedrich-Loeffler-Institut/Federal Research Institute for Animal Health, Institute of Molecular PathogenesisJena, Germany
| | - Inga Eichhorn
- Institute of Microbiology and Epizootics, Free University BerlinBerlin, Germany
| | - Torsten Semmler
- Institute of Microbiology and Epizootics, Free University BerlinBerlin, Germany
- Robert Koch InstituteBerlin, Germany
| | - Lothar H. Wieler
- Institute of Microbiology and Epizootics, Free University BerlinBerlin, Germany
- Robert Koch InstituteBerlin, Germany
| | - Derek Pickard
- Wellcome Trust Sanger Institute, Pathogen GenomicsCambridge, UK
| | - Christian Berens
- Friedrich-Loeffler-Institut/Federal Research Institute for Animal Health, Institute of Molecular PathogenesisJena, Germany
| | - Stefanie A. Barth
- Friedrich-Loeffler-Institut/Federal Research Institute for Animal Health, Institute of Molecular PathogenesisJena, Germany
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Han R, Xu L, Wang T, Liu B, Wang L. A Small Regulatory RNA Contributes to the Preferential Colonization of Escherichia coli O157:H7 in the Large Intestine in Response to a Low DNA Concentration. Front Microbiol 2017; 8:274. [PMID: 28289405 PMCID: PMC5326754 DOI: 10.3389/fmicb.2017.00274] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2016] [Accepted: 02/09/2017] [Indexed: 11/13/2022] Open
Abstract
Enterohemorrhagic Escherichia coli (EHEC) serotype O157:H7 (O157) is one of the most notorious human pathogens, causing severe disease in humans worldwide. O157 specifically colonizes the large intestine of mammals after passing through the small intestine, and this process is influenced by differential signals between the two regions. Small regulatory RNAs (sRNAs) are able to sense and respond to environmental changes and regulate diverse physiological processes in pathogenic bacteria. Although some sRNAs of O157 have been extensively investigated, whether these molecules can sense differences between the small and large intestine and influence the preferential colonization in the large intestine by O157 remains unknown. In this study, we identified a new sRNA, Esr055, in O157 which senses the low DNA concentration in the large intestine and contributes to the preferential colonization of the bacteria in this region. The number of O157 wild-type that adhered to the colon is 30.18 times higher than the number that adhered to the ileum of mice, while the number of the ΔEsr055 mutant that adhered to the colon decreased to 13.27 times higher than the number adhered to the ileum. Furthermore, we found that the expression of Esr055 is directly activated by the regulator, DeoR, and its expression is positively affected by DNA, which is significantly more abundant in the ileum than in the colon of mice. Additionally, combining the results of informatics predictions and transcriptomic analysis, we found that several virulence genes are up-regulated in the ΔEsr055 mutant and five candidate genes (z0568, z0974, z1356, z1926, and z5187) may be its direct targets.
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Affiliation(s)
- Runhua Han
- TEDA Institute of Biological Sciences and Biotechnology, Nankai UniversityTianjin, China; The Key Laboratory of Molecular Microbiology and Technology, Ministry of EducationTianjin, China
| | - Letian Xu
- TEDA Institute of Biological Sciences and Biotechnology, Nankai UniversityTianjin, China; The Key Laboratory of Molecular Microbiology and Technology, Ministry of EducationTianjin, China; Tianjin Key Laboratory of Microbial Functional GenomicsTianjin, China
| | - Ting Wang
- TEDA Institute of Biological Sciences and Biotechnology, Nankai UniversityTianjin, China; The Key Laboratory of Molecular Microbiology and Technology, Ministry of EducationTianjin, China
| | - Bin Liu
- TEDA Institute of Biological Sciences and Biotechnology, Nankai UniversityTianjin, China; The Key Laboratory of Molecular Microbiology and Technology, Ministry of EducationTianjin, China; Tianjin Key Laboratory of Microbial Functional GenomicsTianjin, China
| | - Lei Wang
- TEDA Institute of Biological Sciences and Biotechnology, Nankai UniversityTianjin, China; The Key Laboratory of Molecular Microbiology and Technology, Ministry of EducationTianjin, China; Tianjin Key Laboratory of Microbial Functional GenomicsTianjin, China; State Key Laboratory of Medicinal Chemical Biology, Nankai UniversityTianjin, China
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29
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Abstract
The biogeography of the gut is diverse in its longitudinal axis, as well as within specific microenvironments. Differential oxygenation and nutrient composition drive the membership of microbial communities in these habitats. Moreover, enteric pathogens can orchestrate further modifications to gain a competitive advantage toward host colonization. These pathogens are versatile and adept when exploiting the human colon. They expertly navigate complex environmental cues and interkingdom signaling to colonize and infect their hosts. Here we demonstrate how enterohemorrhagic Escherichia coli (EHEC) uses three sugar-sensing transcription factors, Cra, KdpE, and FusR, to exquisitely regulate the expression of virulence factors associated with its type III secretion system (T3SS) when exposed to various oxygen concentrations. We also explored the effect of mucin-derived nonpreferred carbon sources on EHEC growth and expression of virulence genes. Taken together, the results show that EHEC represses the expression of its T3SS when oxygen is absent, mimicking the largely anaerobic lumen, and activates its T3SS when oxygen is available through Cra. In addition, when EHEC senses mucin-derived sugars heavily present in the O-linked and N-linked glycans of the large intestine, virulence gene expression is initiated. Sugars derived from pectin, a complex plant polysaccharide digested in the large intestine, also increased virulence gene expression. Not only does EHEC sense host- and microbiota-derived interkingdom signals, it also uses oxygen availability and mucin-derived sugars liberated by the microbiota to stimulate expression of the T3SS. This precision in gene regulation allows EHEC to be an efficient pathogen with an extremely low infectious dose. Enteric pathogens have to be crafty when interpreting multiple environmental cues to successfully establish themselves within complex and diverse gut microenvironments. Differences in oxygen tension and nutrient composition determine the biogeography of the gut microbiota and provide unique niches that can be exploited by enteric pathogens. EHEC is an enteric pathogen that colonizes the colon and causes outbreaks of bloody diarrhea and hemolytic-uremic syndrome worldwide. It has a very low infectious dose, which requires it to be an extremely effective pathogen. Hence, here we show that EHEC senses multiple sugar sources and oxygen levels to optimally control the expression of its virulence repertoire. This exquisite regulatory control equips EHEC to sense different intestinal compartments to colonize the host.
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Cordonnier C, Thévenot J, Etienne-Mesmin L, Alric M, Livrelli V, Blanquet-Diot S. Probiotic and enterohemorrhagic Escherichia coli: An effective strategy against a deadly enemy? Crit Rev Microbiol 2016; 43:116-132. [PMID: 27798976 DOI: 10.1080/1040841x.2016.1185602] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Enterohemorrhagic Escherichia coli (EHEC) are major food-borne pathogens that constitute a serious public health threat. Currently, there is no specific treatment available for EHEC infections in human creating an urgent need for the development of alternative therapeutic strategies. Among them, one of the most promising approaches is the use of probiotic microorganisms. Even if many studies have shown the antagonistic effects of probiotic bacteria or yeast on EHEC survival, virulence, adhesion on intestinal epithelium or pathogen-induced inflammatory responses, mechanisms mediating their beneficial effects remain unclear. This review describes EHEC pathogenesis and novel therapeutic strategies, with a particular emphasis on probiotics. The interests and limits of a probiotic-based approach and the way it might be incorporated into global health strategies against EHEC infections will be discussed.
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Affiliation(s)
- Charlotte Cordonnier
- a EA 4678 CIDAM, "Conception, Ingénierie et Développement de l'Aliment et du Médicament", Centre de Recherche en Nutrition Humaine Auvergne , Université d'Auvergne , Clermont-Ferrand , France.,b M2iSH, "Microbes, Intestin, Inflammation et Susceptibilité de l'Hôte" , UMR Inserm/Université d'Auvergne U1071, USC-INRA 2018, Centre de Recherche en Nutrition Humaine Auvergne, Université d'Auvergne , Clermont-Ferrand , France
| | - Jonathan Thévenot
- a EA 4678 CIDAM, "Conception, Ingénierie et Développement de l'Aliment et du Médicament", Centre de Recherche en Nutrition Humaine Auvergne , Université d'Auvergne , Clermont-Ferrand , France.,b M2iSH, "Microbes, Intestin, Inflammation et Susceptibilité de l'Hôte" , UMR Inserm/Université d'Auvergne U1071, USC-INRA 2018, Centre de Recherche en Nutrition Humaine Auvergne, Université d'Auvergne , Clermont-Ferrand , France
| | - Lucie Etienne-Mesmin
- a EA 4678 CIDAM, "Conception, Ingénierie et Développement de l'Aliment et du Médicament", Centre de Recherche en Nutrition Humaine Auvergne , Université d'Auvergne , Clermont-Ferrand , France.,b M2iSH, "Microbes, Intestin, Inflammation et Susceptibilité de l'Hôte" , UMR Inserm/Université d'Auvergne U1071, USC-INRA 2018, Centre de Recherche en Nutrition Humaine Auvergne, Université d'Auvergne , Clermont-Ferrand , France
| | - Monique Alric
- a EA 4678 CIDAM, "Conception, Ingénierie et Développement de l'Aliment et du Médicament", Centre de Recherche en Nutrition Humaine Auvergne , Université d'Auvergne , Clermont-Ferrand , France
| | - Valérie Livrelli
- b M2iSH, "Microbes, Intestin, Inflammation et Susceptibilité de l'Hôte" , UMR Inserm/Université d'Auvergne U1071, USC-INRA 2018, Centre de Recherche en Nutrition Humaine Auvergne, Université d'Auvergne , Clermont-Ferrand , France.,c Service de Bactériologie , CHU Clermont-Ferrand , Clermont-Ferrand , France
| | - Stéphanie Blanquet-Diot
- a EA 4678 CIDAM, "Conception, Ingénierie et Développement de l'Aliment et du Médicament", Centre de Recherche en Nutrition Humaine Auvergne , Université d'Auvergne , Clermont-Ferrand , France
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31
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Roussel C, Cordonnier C, Galia W, Le Goff O, Thévenot J, Chalancon S, Alric M, Thevenot-Sergentet D, Leriche F, Van de Wiele T, Livrelli V, Blanquet-Diot S. Increased EHEC survival and virulence gene expression indicate an enhanced pathogenicity upon simulated pediatric gastrointestinal conditions. Pediatr Res 2016; 80:734-743. [PMID: 27429202 DOI: 10.1038/pr.2016.144] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/18/2016] [Accepted: 05/15/2016] [Indexed: 11/09/2022]
Abstract
BACKGROUND Enterohemorrhagic Escherichia coli (EHEC) are major foodborne pathogens that constitute a serious public health threat, mainly in young children. Shiga toxins (Stx) are the main virulence determinants of EHEC pathogenesis but adhesins like intimin (eae) and Long polar fimbriae (Lpf) also contribute to infection. The TNO GastroIntestinal Model (TIM) was used for a comparative study of EHEC O157:H7 survival and virulence under adult and child digestive conditions. METHODS Survival kinetics in the in vitro digestive tract were determined by plating while bacterial viability was assessed by flow cytometry analysis. Expression of stx, eae, and lpf genes was followed by reverse transcriptase-quantitative PCR (RT-qPCR) and Stx production was measured by ELISA (enzyme-linked immunosorbent assay). RESULTS Upon gastrointestinal passage, a higher amount of viable cells was found in the simulated ileal effluents of children compared to that of adults (with 34 and 6% of viable cells, respectively). Expression levels of virulence genes were up to 125-fold higher in children. Stx was detected only in child ileal effluents. CONCLUSION Differences in digestive physicochemical parameters may partially explain why children are more susceptible to EHEC infection than adults. Such data are essential for a full understanding of EHEC pathogenesis and would help in designing novel therapeutic approaches.
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Affiliation(s)
- Charlène Roussel
- EA 4678 CIDAM, Conception Ingénierie et Développement de l'Aliment et du Médicament, Université d'Auvergne, Clermont-Ferrand, France.,CMet, Center for Microbial Ecology and Technology, Ghent University, Ghent, Belgium
| | - Charlotte Cordonnier
- EA 4678 CIDAM, Conception Ingénierie et Développement de l'Aliment et du Médicament, Université d'Auvergne, Clermont-Ferrand, France.,M2iSH, Microbes, Intestin, Inflammation et Susceptibilité de l'Hôte UMR INSERM/Université d'Auvergne, Université d'Auvergne, Clermont-Ferrand, France
| | - Wessam Galia
- EA 4678 CIDAM, Conception Ingénierie et Développement de l'Aliment et du Médicament, Université d'Auvergne, Clermont-Ferrand, France.,UMR 5557 Ecologie Microbienne, Research Group on Bacterial Opportunistic Pathogens and Environment, CNRS, VetAgro Sup and Université de Lyon, Lyon, France.,Unité CALYTISS, VetAgro Sup, Lempdes, France
| | - Olivier Le Goff
- EA 4678 CIDAM, Conception Ingénierie et Développement de l'Aliment et du Médicament, Université d'Auvergne, Clermont-Ferrand, France
| | - Jonathan Thévenot
- EA 4678 CIDAM, Conception Ingénierie et Développement de l'Aliment et du Médicament, Université d'Auvergne, Clermont-Ferrand, France.,M2iSH, Microbes, Intestin, Inflammation et Susceptibilité de l'Hôte UMR INSERM/Université d'Auvergne, Université d'Auvergne, Clermont-Ferrand, France
| | - Sandrine Chalancon
- EA 4678 CIDAM, Conception Ingénierie et Développement de l'Aliment et du Médicament, Université d'Auvergne, Clermont-Ferrand, France
| | - Monique Alric
- EA 4678 CIDAM, Conception Ingénierie et Développement de l'Aliment et du Médicament, Université d'Auvergne, Clermont-Ferrand, France
| | - Delphine Thevenot-Sergentet
- UMR 5557 Ecologie Microbienne, Research Group on Bacterial Opportunistic Pathogens and Environment, CNRS, VetAgro Sup and Université de Lyon, Lyon, France.,Laboratoire d'Etude des Microorganismes Alimentaires Pathogènes, French National Reference Laboratory for Escherichia coli including Shiga Toxin-Producing E. coli, VetAgro Sup, Université de Lyon, Marcy l'Etoile, France
| | | | - Tom Van de Wiele
- CMet, Center for Microbial Ecology and Technology, Ghent University, Ghent, Belgium
| | - Valérie Livrelli
- M2iSH, Microbes, Intestin, Inflammation et Susceptibilité de l'Hôte UMR INSERM/Université d'Auvergne, Université d'Auvergne, Clermont-Ferrand, France.,Service de Bactériologie, CHU de Clermont-Ferrand, Clermont-Ferrand, France
| | - Stéphanie Blanquet-Diot
- EA 4678 CIDAM, Conception Ingénierie et Développement de l'Aliment et du Médicament, Université d'Auvergne, Clermont-Ferrand, France
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32
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Abstract
Enterohemorrhagic Escherichia coli (EHEC) is a highly pathogenic bacterial strain capable of causing watery or bloody diarrhea, the latter termed hemorrhagic colitis, and hemolytic-uremic syndrome (HUS). HUS is defined as the simultaneous development of non-immune hemolytic anemia, thrombocytopenia, and acute renal failure. The mechanism by which EHEC bacteria colonize and cause severe colitis, followed by renal failure with activated blood cells, as well as neurological symptoms, involves the interaction of bacterial virulence factors and specific pathogen-associated molecular patterns with host cells as well as the host response. The innate immune host response comprises the release of antimicrobial peptides as well as cytokines and chemokines in addition to activation and/or injury to leukocytes, platelets, and erythrocytes and activation of the complement system. Some of the bacterial interactions with the host may be protective in nature, but, when excessive, contribute to extensive tissue injury, inflammation, and thrombosis, effects that may worsen the clinical outcome of EHEC infection. This article describes aspects of the host response occurring during EHEC infection and their effects on specific organs.
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Thévenot J, Cordonnier C, Rougeron A, Le Goff O, Nguyen HTT, Denis S, Alric M, Livrelli V, Blanquet-Diot S. Enterohemorrhagic Escherichia coli infection has donor-dependent effect on human gut microbiota and may be antagonized by probiotic yeast during interaction with Peyer's patches. Appl Microbiol Biotechnol 2015; 99:9097-110. [PMID: 26084888 DOI: 10.1007/s00253-015-6704-0] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2015] [Revised: 05/13/2015] [Accepted: 05/17/2015] [Indexed: 01/05/2023]
Abstract
Enterohemorrhagic Escherichia coli (EHEC) are major food-borne pathogens responsible for serious infections ranging from mild diarrhea to hemorrhagic colitis and life-threatening complications. Shiga toxins (Stxs) are the main virulence factor of EHEC. The antagonistic effect of a prophylactic treatment with the probiotic strain Saccharomyces cerevisiae against EHEC O157:H7 was investigated using complementary in vitro human colonic model and in vivo murine ileal loop assays. In vitro, the probiotic treatment had no effect on O157:H7 survival but favorably influenced gut microbiota activity through modulation of short-chain fatty acid production, increasing acetate production and decreasing that of butyrate. Both pathogen and probiotic strains had individual-dependent effects on human gut microbiota. For the first time, stx expression was followed in human colonic environment: at 9 and 12 h post EHEC infection, probiotic treatment significantly decreased stx mRNA levels. Besides, in murine ileal loops, the probiotic yeast specifically exerted a trophic effect on intestinal mucosa and inhibited O157:H7 interactions with Peyer's patches and subsequent hemorrhagic lesions. Taken together, the results suggest that S. cerevisiae may be useful in the fight against EHEC infection and that host associated factors such as microbiota could influence clinical evolution of EHEC infection and the effectiveness of probiotics.
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Affiliation(s)
- J Thévenot
- Centre de Recherche en Nutrition Humaine Auvergne, EA 4678 CIDAM, Conception Ingénierie et Développement de l'Aliment et du Médicament, Clermont Université, Université d'Auvergne, Clermont-Ferrand, France.,Centre de Recherche en Nutrition Humaine Auvergne, M2iSH, Microbes, Intestin, Inflammation et Susceptibilité de l'Hôte UMR INSERM / Université d'Auvergne U1071 USC-INRA 2018, Clermont Université, Université d'Auvergne, Clermont-Ferrand, France
| | - C Cordonnier
- Centre de Recherche en Nutrition Humaine Auvergne, EA 4678 CIDAM, Conception Ingénierie et Développement de l'Aliment et du Médicament, Clermont Université, Université d'Auvergne, Clermont-Ferrand, France.,Centre de Recherche en Nutrition Humaine Auvergne, M2iSH, Microbes, Intestin, Inflammation et Susceptibilité de l'Hôte UMR INSERM / Université d'Auvergne U1071 USC-INRA 2018, Clermont Université, Université d'Auvergne, Clermont-Ferrand, France
| | - A Rougeron
- Centre de Recherche en Nutrition Humaine Auvergne, M2iSH, Microbes, Intestin, Inflammation et Susceptibilité de l'Hôte UMR INSERM / Université d'Auvergne U1071 USC-INRA 2018, Clermont Université, Université d'Auvergne, Clermont-Ferrand, France
| | - O Le Goff
- Centre de Recherche en Nutrition Humaine Auvergne, EA 4678 CIDAM, Conception Ingénierie et Développement de l'Aliment et du Médicament, Clermont Université, Université d'Auvergne, Clermont-Ferrand, France
| | - H T T Nguyen
- Centre de Recherche en Nutrition Humaine Auvergne, M2iSH, Microbes, Intestin, Inflammation et Susceptibilité de l'Hôte UMR INSERM / Université d'Auvergne U1071 USC-INRA 2018, Clermont Université, Université d'Auvergne, Clermont-Ferrand, France
| | - S Denis
- Centre de Recherche en Nutrition Humaine Auvergne, EA 4678 CIDAM, Conception Ingénierie et Développement de l'Aliment et du Médicament, Clermont Université, Université d'Auvergne, Clermont-Ferrand, France
| | - M Alric
- Centre de Recherche en Nutrition Humaine Auvergne, EA 4678 CIDAM, Conception Ingénierie et Développement de l'Aliment et du Médicament, Clermont Université, Université d'Auvergne, Clermont-Ferrand, France
| | - V Livrelli
- Centre de Recherche en Nutrition Humaine Auvergne, M2iSH, Microbes, Intestin, Inflammation et Susceptibilité de l'Hôte UMR INSERM / Université d'Auvergne U1071 USC-INRA 2018, Clermont Université, Université d'Auvergne, Clermont-Ferrand, France.,Service de Bactériologie, CHU Clermont-Ferrand, Clermont-Ferrand, France
| | - S Blanquet-Diot
- Centre de Recherche en Nutrition Humaine Auvergne, EA 4678 CIDAM, Conception Ingénierie et Développement de l'Aliment et du Médicament, Clermont Université, Université d'Auvergne, Clermont-Ferrand, France.
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Yang B, Feng L, Wang F, Wang L. Enterohemorrhagic Escherichia coli senses low biotin status in the large intestine for colonization and infection. Nat Commun 2015; 6:6592. [PMID: 25791315 PMCID: PMC4382993 DOI: 10.1038/ncomms7592] [Citation(s) in RCA: 72] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2014] [Accepted: 02/10/2015] [Indexed: 12/17/2022] Open
Abstract
Enterohemorrhagic Escherichia coli (EHEC) is an important foodborne pathogen that infects humans by colonizing the large intestine. Here we identify a virulence-regulating pathway in which the biotin protein ligase BirA signals to the global regulator Fur, which in turn activates LEE (locus of enterocyte effacement) genes to promote EHEC adherence in the low-biotin large intestine. LEE genes are repressed in the high-biotin small intestine, thus preventing adherence and ensuring selective colonization of the large intestine. The presence of this pathway in all nine EHEC serotypes tested indicates that it is an important evolutionary strategy for EHEC. The pathway is incomplete in closely related small-intestinal enteropathogenic E. coli due to the lack of the Fur response to BirA. Mice fed with a biotin-rich diet show significantly reduced EHEC adherence, indicating that biotin might be useful to prevent EHEC infection in humans. Enterohaemorrhagic Escherichia coli (EHEC) is an important foodborne pathogen that colonizes the large intestine. Here, the authors identify a signalling pathway that controls EHEC adherence to host cells in response to variations in biotin levels, ensuring selective colonization of the large intestine.
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Affiliation(s)
- Bin Yang
- 1] TEDA Institute of Biological Sciences and Biotechnology, Nankai University, TEDA, Tianjin 300457, P.R. China [2] Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Tianjin 300071, P.R. China
| | - Lu Feng
- 1] TEDA Institute of Biological Sciences and Biotechnology, Nankai University, TEDA, Tianjin 300457, P.R. China [2] Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Tianjin 300071, P.R. China [3] Tianjin Key Laboratory of Microbial Functional Genomics, Tianjin 300457, P.R. China [4] State Key Laboratory of Medicinal Chemical Biology, Nankai University, Tianjin 300071, P.R. China [5] SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin 300072, P.R. China
| | - Fang Wang
- 1] TEDA Institute of Biological Sciences and Biotechnology, Nankai University, TEDA, Tianjin 300457, P.R. China [2] Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Tianjin 300071, P.R. China
| | - Lei Wang
- 1] TEDA Institute of Biological Sciences and Biotechnology, Nankai University, TEDA, Tianjin 300457, P.R. China [2] Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Tianjin 300071, P.R. China [3] Tianjin Key Laboratory of Microbial Functional Genomics, Tianjin 300457, P.R. China [4] State Key Laboratory of Medicinal Chemical Biology, Nankai University, Tianjin 300071, P.R. China
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35
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Wyrsch E, Roy Chowdhury P, Abraham S, Santos J, Darling AE, Charles IG, Chapman TA, Djordjevic SP. Comparative genomic analysis of a multiple antimicrobial resistant enterotoxigenic E. coli O157 lineage from Australian pigs. BMC Genomics 2015; 16:165. [PMID: 25888127 PMCID: PMC4384309 DOI: 10.1186/s12864-015-1382-y] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2014] [Accepted: 02/23/2015] [Indexed: 01/01/2023] Open
Abstract
Background Enterotoxigenic Escherichia coli (ETEC) are a major economic threat to pig production globally, with serogroups O8, O9, O45, O101, O138, O139, O141, O149 and O157 implicated as the leading diarrhoeal pathogens affecting pigs below four weeks of age. A multiple antimicrobial resistant ETEC O157 (O157 SvETEC) representative of O157 isolates from a pig farm in New South Wales, Australia that experienced repeated bouts of pre- and post-weaning diarrhoea resulting in multiple fatalities was characterized here. Enterohaemorrhagic E. coli (EHEC) O157:H7 cause both sporadic and widespread outbreaks of foodborne disease, predominantly have a ruminant origin and belong to the ST11 clonal complex. Here, for the first time, we conducted comparative genomic analyses of two epidemiologically-unrelated porcine, disease-causing ETEC O157; E. coli O157 SvETEC and E. coli O157:K88 734/3, and examined their phylogenetic relationship with EHEC O157:H7. Results O157 SvETEC and O157:K88 734/3 belong to a novel sequence type (ST4245) that comprises part of the ST23 complex and are genetically distinct from EHEC O157. Comparative phylogenetic analysis using PhyloSift shows that E. coli O157 SvETEC and E. coli O157:K88 734/3 group into a single clade and are most similar to the extraintestinal avian pathogenic Escherichia coli (APEC) isolate O78 that clusters within the ST23 complex. Genome content was highly similar between E. coli O157 SvETEC, O157:K88 734/3 and APEC O78, with variability predominantly limited to laterally acquired elements, including prophages, plasmids and antimicrobial resistance gene loci. Putative ETEC virulence factors, including the toxins STb and LT and the K88 (F4) adhesin, were conserved between O157 SvETEC and O157:K88 734/3. The O157 SvETEC isolate also encoded the heat stable enterotoxin STa and a second allele of STb, whilst a prophage within O157:K88 734/3 encoded the serum survival gene bor. Both isolates harbor a large repertoire of antibiotic resistance genes but their association with mobile elements remains undetermined. Conclusions We present an analysis of the first draft genome sequences of two epidemiologically-unrelated, pathogenic ETEC O157. E. coli O157 SvETEC and E. coli O157:K88 734/3 belong to the ST23 complex and are phylogenetically distinct to EHEC O157 lineages that reside within the ST11 complex. Electronic supplementary material The online version of this article (doi:10.1186/s12864-015-1382-y) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Ethan Wyrsch
- The ithree institute, University of Technology Sydney, P.O. Box 123, Broadway, NSW, 2007, Australia.
| | - Piklu Roy Chowdhury
- The ithree institute, University of Technology Sydney, P.O. Box 123, Broadway, NSW, 2007, Australia. .,NSW Department of Primary Industries, Elizabeth Macarthur Agricultural Institute, Private Bag 4008, Narellan, NSW, 2567, Australia.
| | - Sam Abraham
- NSW Department of Primary Industries, Elizabeth Macarthur Agricultural Institute, Private Bag 4008, Narellan, NSW, 2567, Australia. .,School of Animal and Veterinary Sciences, University of Adelaide, Adelaide, South Australia, 5371, Australia.
| | - Jerran Santos
- The ithree institute, University of Technology Sydney, P.O. Box 123, Broadway, NSW, 2007, Australia.
| | - Aaron E Darling
- The ithree institute, University of Technology Sydney, P.O. Box 123, Broadway, NSW, 2007, Australia.
| | - Ian G Charles
- The ithree institute, University of Technology Sydney, P.O. Box 123, Broadway, NSW, 2007, Australia.
| | - Toni A Chapman
- NSW Department of Primary Industries, Elizabeth Macarthur Agricultural Institute, Private Bag 4008, Narellan, NSW, 2567, Australia.
| | - Steven P Djordjevic
- The ithree institute, University of Technology Sydney, P.O. Box 123, Broadway, NSW, 2007, Australia.
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Iversen H, Lindbäck T, L’Abée-Lund TM, Roos N, Aspholm M, Stenfors Arnesen L. The gut bacterium Bacteroides thetaiotaomicron influences the virulence potential of the enterohemorrhagic Escherichia coli O103:H25. PLoS One 2015; 10:e0118140. [PMID: 25719195 PMCID: PMC4342160 DOI: 10.1371/journal.pone.0118140] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2014] [Accepted: 12/17/2014] [Indexed: 11/18/2022] Open
Abstract
Enterohemorrhagic E. coli (EHEC) is associated with severe gastrointestinal disease. Upon entering the gastrointestinal tract, EHEC is exposed to a fluctuating environment and a myriad of other bacterial species. To establish an infection, EHEC strains have to modulate their gene expression according to the GI tract environment. In order to explore the interspecies interactions between EHEC and an human intestinal commensal, the global gene expression profile was determined of EHEC O103:H25 (EHEC NIPH-11060424) co-cultured with B. thetaiotaomicron (CCUG 10774) or grown in the presence of spent medium from B. thetaiotaomicron. Microarray analysis revealed that approximately 1% of the EHEC NIPH-11060424 genes were significantly up-regulated both in co-culture (30 genes) and in the presence of spent medium (44 genes), and that the affected genes differed between the two conditions. In co-culture, genes encoding structural components of the type three secretion system were among the most affected genes with an almost 4-fold up-regulation, while the most affected genes in spent medium were involved in chemotaxis and were more than 3-fold up-regulated. The operons for type three secretion system (TTSS) are located on the Locus of enterocyte effacement (LEE) pathogenicity island, and qPCR showed that genes of all five operons (LEE1-LEE5) were up-regulated. Moreover, an increased adherence to HeLa cells was observed in EHEC NIPH-11060424 exposed to B. thetaiotaomicron. Expression of stx2 genes, encoding the main virulence factor of EHEC, was down-regulated in both conditions (co-culture/spent medium). These results show that expression of EHEC genes involved in colonization and virulence is modulated in response to direct interspecies contact between cells, or to diffusible factors released from B. thetaiotaomicron. Such interspecies interactions could allow the pathogen to recognize its predilection site and modulate its behaviour accordingly, thus increasing the efficiency of colonization of the colon mucosa, facilitating its persistence and increasing its virulence potential.
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Affiliation(s)
- Hildegunn Iversen
- Department of Food Safety and Infection Biology, Norwegian University of Life Sciences, Oslo, Norway
| | - Toril Lindbäck
- Department of Food Safety and Infection Biology, Norwegian University of Life Sciences, Oslo, Norway
| | - Trine M. L’Abée-Lund
- Department of Food Safety and Infection Biology, Norwegian University of Life Sciences, Oslo, Norway
| | - Norbert Roos
- Department of Biosciences, University of Oslo, Oslo, Norway
| | - Marina Aspholm
- Department of Food Safety and Infection Biology, Norwegian University of Life Sciences, Oslo, Norway
| | - Lotte Stenfors Arnesen
- Department of Food Safety and Infection Biology, Norwegian University of Life Sciences, Oslo, Norway
- * E-mail:
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37
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Affiliation(s)
- Hiroshi Ohno
- Laboratory for Intestinal Ecosystem, RIKEN Center for Integrative Medical Sciences, Yokohama, Kanagawa, Japan
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38
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De Biase D, Lund PA. The Escherichia coli Acid Stress Response and Its Significance for Pathogenesis. ADVANCES IN APPLIED MICROBIOLOGY 2015; 92:49-88. [PMID: 26003933 DOI: 10.1016/bs.aambs.2015.03.002] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Escherichia coli has a remarkable ability to survive low pH and possesses a number of different genetic systems that enable it to do this. These may be expressed constitutively, typically in stationary phase, or induced by growth under a variety of conditions. The activities of these systems have been implicated in the ability of E. coli to pass the acidic barrier of the stomach and to become established in the gastrointestinal tract, something causing serious infections. However, much of the work characterizing these systems has been done on standard laboratory strains of E. coli and under conditions which do not closely resemble those found in the human gut. Here we review what is known about acid resistance in E. coli as a model laboratory organism and in the context of its lifestyle as an inhabitant-sometimes an unwelcome one-of the human gut.
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Tan X, Xiao H, Han Y, Hong X, Cui Q, Zhou Z. Encoded protein from ycbR gene of enterohemorrhagic Escherichia coli O157:H7 associated with adherence to HEp-2 cells. Microbiol Res 2014; 169:855-61. [DOI: 10.1016/j.micres.2014.03.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2013] [Revised: 02/28/2014] [Accepted: 03/03/2014] [Indexed: 01/14/2023]
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40
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Landes Highlights. Gut Microbes 2014. [PMCID: PMC3744509 DOI: 10.4161/gmic.25732] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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Arroyo-López FN, Blanquet-Diot S, Denis S, Thévenot J, Chalancon S, Alric M, Rodríguez-Gómez F, Romero-Gil V, Jiménez-Díaz R, Garrido-Fernández A. Survival of pathogenic and lactobacilli species of fermented olives during simulated human digestion. Front Microbiol 2014; 5:540. [PMID: 25352842 PMCID: PMC4196563 DOI: 10.3389/fmicb.2014.00540] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2014] [Accepted: 09/29/2014] [Indexed: 11/21/2022] Open
Abstract
The present survey uses a dynamic gastric and small intestinal model to assess the survival of one pathogenic (Escherichia coli O157:H7 EDL 933) and three lactobacilli bacteria with probiotic potential (Lactobacillus rhamnosus GG, L. pentosus TOMC-LAB2, and L. pentosus TOMC-LAB4) during their passage through the human gastrointestinal tract using fermented olives as the food matrix. The data showed that the survival of the E. coli strain in the stomach and duodenum was very low, while its transit through the distal parts (jejunum and ileum) resulted in an increase in the pathogen population. The production of Shiga toxins by this enterohemorrhagic microorganism in the ileal effluents of the in vitro system was too low to be detected by ELISA assays. On the contrary, the three lactobacilli species assayed showed a considerable resistance to the gastric digestion, but not to the intestinal one, which affected their survival, and was especially evident in the case of both L. pentosus strains. In spite of this, high population levels for all assayed microorganisms were recovered at the end of the gastrointestinal passage. The results obtained in the present study show the potential use of table olives as a vehicle of beneficial microorganisms to the human body, as well as the need for good hygienic practices on the part of olive manufacturers in order to avoid the possibility of contamination by food-borne pathogens.
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Affiliation(s)
- Francisco N Arroyo-López
- Biotecnología de Alimentos, Instituto de la Grasa - Consejo Superior de Investigaciones Científicas Seville, Spain
| | - Stéphanie Blanquet-Diot
- Centre de Recherche en Nutrition Humaine Auvergne, EA 4678, Conception Ingénierie et Développement de l'Aliment et du Médicament, Clermont Université - Université d'Auvergne Clermont-Ferrand, France
| | - Sylvain Denis
- Centre de Recherche en Nutrition Humaine Auvergne, EA 4678, Conception Ingénierie et Développement de l'Aliment et du Médicament, Clermont Université - Université d'Auvergne Clermont-Ferrand, France
| | - Jonathan Thévenot
- Centre de Recherche en Nutrition Humaine Auvergne, EA 4678, Conception Ingénierie et Développement de l'Aliment et du Médicament, Clermont Université - Université d'Auvergne Clermont-Ferrand, France ; Centre de Recherche en Nutrition Humaine Auvergne, M2iSH, UMR INSERM/Université d'Auvergne U1071 USC-INRA 2018, Clermont Université - Université d'Auvergne Clermont-Ferrand, France
| | - Sandrine Chalancon
- Centre de Recherche en Nutrition Humaine Auvergne, EA 4678, Conception Ingénierie et Développement de l'Aliment et du Médicament, Clermont Université - Université d'Auvergne Clermont-Ferrand, France
| | - Monique Alric
- Centre de Recherche en Nutrition Humaine Auvergne, EA 4678, Conception Ingénierie et Développement de l'Aliment et du Médicament, Clermont Université - Université d'Auvergne Clermont-Ferrand, France
| | - Francisco Rodríguez-Gómez
- Biotecnología de Alimentos, Instituto de la Grasa - Consejo Superior de Investigaciones Científicas Seville, Spain
| | - Verónica Romero-Gil
- Biotecnología de Alimentos, Instituto de la Grasa - Consejo Superior de Investigaciones Científicas Seville, Spain
| | - Rufino Jiménez-Díaz
- Biotecnología de Alimentos, Instituto de la Grasa - Consejo Superior de Investigaciones Científicas Seville, Spain
| | - Antonio Garrido-Fernández
- Biotecnología de Alimentos, Instituto de la Grasa - Consejo Superior de Investigaciones Científicas Seville, Spain
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Transcriptome analysis of Escherichia coli O157:H7 grown in vitro in the sterile-filtrated cecal content of human gut microbiota associated rats reveals an adaptive expression of metabolic and virulence genes. Microbes Infect 2014; 17:23-33. [PMID: 25290220 DOI: 10.1016/j.micinf.2014.09.008] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2014] [Revised: 09/19/2014] [Accepted: 09/19/2014] [Indexed: 12/12/2022]
Abstract
In developed countries, enterohemorrhagic Escherichia coli (EHEC) O157:H7 is a leading cause of bloody diarrhea and renal failures in human. Understanding strategies employed by EHEC to colonize the intestine is of major importance since to date no cure exists to eradicate the pathogen. In this study, the adaptive response of EHEC to the intestinal milieu conditioned by a human microbiota was examined. A transcriptomic analysis was performed on the EHEC strain EDL933 incubated in vitro in the sterile-filtrated cecal content of human microbiota-associated rats (HMC) compared with EDL933 incubated in the sterile-filtrated cecal content of germ-free rat (GFC). EDL933 switches from a glycolytic metabolic profile in the GFC to an anaplerotic metabolic profile in HMC. The expression of several catabolism genes was strongly affected such as those involved in the utilization of sugars, glycerol, N-acetylneuraminic acid, amino acids and secondary metabolites. Interestingly, expression level of critical EHEC O157:H7 virulence genes including genes from the locus of enterocyte effacement was reduced in HMC. Altogether, these results contribute to the understanding of EHEC adaptive response to a digestive content and highlight the ability of the microbiota to repress EHEC virulence gene expression.
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