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Castro VS, Ngo S, Stanford K. Influence of temperature and pH on induction of Shiga toxin Stx1a in Escherichia coli. Front Microbiol 2023; 14:1181027. [PMID: 37485504 PMCID: PMC10359099 DOI: 10.3389/fmicb.2023.1181027] [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: 03/06/2023] [Accepted: 06/20/2023] [Indexed: 07/25/2023] Open
Abstract
Shiga toxin-producing strains represent pathogenic group that is of concern in food production. The present study evaluated forty-eight E. coli isolates (11 with intact stx gene, while remaining isolates presented only stx-fragments) for Shiga toxin production. The four most expressive stx-producers (O26, O103, O145, and O157) were selected to evaluate effects of pH (3.5, 4.5, and 7) and temperature (35, 40, and 50°C). After determining acid stress effects in media on Stx-induction, we mimicked "in natura" conditions using milk, apple, and orange juices. Only isolates that showed the presence of intact stx gene (11/48) produced Shiga toxin. In addition, acid pH had a role in down-regulating the production of Shiga toxin, in both lactic acid and juices. In contrast, non-lethal heating (40°C), when in neutral pH and milk was a favorable environment to induce Shiga toxin. Lastly, two isolates (O26 and O103) showed a higher capacity to produce Shiga toxin and were included in a genomic cluster with other E. coli involved in worldwide foodborne outbreaks. The induction of this toxin when subjected to 40°C may represent a potential risk to the consumer, since the pathogenic effect of oral ingestion of Shiga toxin has already been proved in an animal model.
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Munhoz DD, Richards AC, Santos FF, Mulvey MA, Piazza RMF. E. coli Common pili promote the fitness and virulence of a hybrid aEPEC/ExPEC strain within diverse host environments. Gut Microbes 2023; 15:2190308. [PMID: 36949030 PMCID: PMC10038029 DOI: 10.1080/19490976.2023.2190308] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/22/2022] [Accepted: 03/07/2023] [Indexed: 03/24/2023] Open
Abstract
Pathogenic subsets of Escherichia coli include diarrheagenic (DEC) strains that cause disease within the gut and extraintestinal pathogenic E. coli (ExPEC) strains that are linked with urinary tract infections, bacteremia, and other infections outside of intestinal tract. Among DEC strains is an emergent pathotype known as atypical enteropathogenic E. coli (aEPEC), which can cause severe diarrhea. Recent sequencing efforts revealed that some E. coli strains possess genetic features that are characteristic of both DEC and ExPEC isolates. BA1250 is a newly reclassified hybrid strain with characteristics of aEPEC and ExPEC. This strain was isolated from a child with diarrhea, but its genetic features indicate that it might have the capacity to cause disease at extraintestinal sites. The spectrum of adhesins encoded by hybrid strains like BA1250 are expected to be especially important in facilitating colonization of diverse niches. E. coli common pilus (ECP) is an adhesin expressed by many E. coli pathogens, but how it impacts hybrid strains has not been ascertained. Here, using zebrafish larvae as surrogate hosts to model both gut colonization and extraintestinal infections, we found that ECP can act as a multi-niche colonization and virulence factor for BA1250. Furthermore, our results indicate that ECP-related changes in activation of envelope stress response pathways may alter the fitness of BA1250. Using an in silico approach, we also delineated the broader repertoire of adhesins that are encoded by BA1250, and provide evidence that the expression of at least a few of these varies in the absence of functional ECP.
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Affiliation(s)
| | - Amanda C. Richards
- Division of Microbiology and Immunology, Department of Pathology, University of Utah, Salt Lake, UT, USA
| | - Fernanda F. Santos
- Laboratório Alerta, Departamento de Medicina, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, SP, Brazil
| | - Matthew A. Mulvey
- Division of Microbiology and Immunology, Department of Pathology, University of Utah, Salt Lake, UT, USA
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Comparative Pathogenomics of Escherichia coli: Polyvalent Vaccine Target Identification through Virulome Analysis. Infect Immun 2021; 89:e0011521. [PMID: 33941580 PMCID: PMC8281228 DOI: 10.1128/iai.00115-21] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Comparative genomics of bacterial pathogens has been useful for revealing potential virulence factors. Escherichia coli is a significant cause of human morbidity and mortality worldwide but can also exist as a commensal in the human gastrointestinal tract. With many sequenced genomes, it has served as a model organism for comparative genomic studies to understand the link between genetic content and potential for virulence. To date, however, no comprehensive analysis of its complete “virulome” has been performed for the purpose of identifying universal or pathotype-specific targets for vaccine development. Here, we describe the construction of a pathotype database of 107 well-characterized completely sequenced pathogenic and nonpathogenic E. coli strains, which we annotated for major virulence factors (VFs). The data are cross referenced for patterns against pathotype, phylogroup, and sequence type, and the results were verified against all 1,348 complete E. coli chromosomes in the NCBI RefSeq database. Our results demonstrate that phylogroup drives many of the “pathotype-associated” VFs, and ExPEC-associated VFs are found predominantly within the B2/D/F/G phylogenetic clade, suggesting that these phylogroups are better adapted to infect human hosts. Finally, we used this information to propose polyvalent vaccine targets with specificity toward extraintestinal strains, targeting key invasive strategies, including immune evasion (group 2 capsule), iron acquisition (FyuA, IutA, and Sit), adherence (SinH, Afa, Pap, Sfa, and Iha), and toxins (Usp, Sat, Vat, Cdt, Cnf1, and HlyA). While many of these targets have been proposed before, this work is the first to examine their pathotype and phylogroup distribution and how they may be targeted together to prevent disease.
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Ageorges V, Monteiro R, Leroy S, Burgess CM, Pizza M, Chaucheyras-Durand F, Desvaux M. Molecular determinants of surface colonisation in diarrhoeagenic Escherichia coli (DEC): from bacterial adhesion to biofilm formation. FEMS Microbiol Rev 2021; 44:314-350. [PMID: 32239203 DOI: 10.1093/femsre/fuaa008] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Accepted: 03/31/2020] [Indexed: 12/11/2022] Open
Abstract
Escherichia coli is primarily known as a commensal colonising the gastrointestinal tract of infants very early in life but some strains being responsible for diarrhoea, which can be especially severe in young children. Intestinal pathogenic E. coli include six pathotypes of diarrhoeagenic E. coli (DEC), namely, the (i) enterotoxigenic E. coli, (ii) enteroaggregative E. coli, (iii) enteropathogenic E. coli, (iv) enterohemorragic E. coli, (v) enteroinvasive E. coli and (vi) diffusely adherent E. coli. Prior to human infection, DEC can be found in natural environments, animal reservoirs, food processing environments and contaminated food matrices. From an ecophysiological point of view, DEC thus deal with very different biotopes and biocoenoses all along the food chain. In this context, this review focuses on the wide range of surface molecular determinants acting as surface colonisation factors (SCFs) in DEC. In the first instance, SCFs can be broadly discriminated into (i) extracellular polysaccharides, (ii) extracellular DNA and (iii) surface proteins. Surface proteins constitute the most diverse group of SCFs broadly discriminated into (i) monomeric SCFs, such as autotransporter (AT) adhesins, inverted ATs, heat-resistant agglutinins or some moonlighting proteins, (ii) oligomeric SCFs, namely, the trimeric ATs and (iii) supramolecular SCFs, including flagella and numerous pili, e.g. the injectisome, type 4 pili, curli chaperone-usher pili or conjugative pili. This review also details the gene regulatory network of these numerous SCFs at the various stages as it occurs from pre-transcriptional to post-translocational levels, which remains to be fully elucidated in many cases.
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Affiliation(s)
- Valentin Ageorges
- Université Clermont Auvergne, INRAE, MEDiS, F-63000 Clermont-Ferrand, France
| | - Ricardo Monteiro
- Université Clermont Auvergne, INRAE, MEDiS, F-63000 Clermont-Ferrand, France.,GSK, Via Fiorentina 1, 53100 Siena, Italy
| | - Sabine Leroy
- Université Clermont Auvergne, INRAE, MEDiS, F-63000 Clermont-Ferrand, France
| | - Catherine M Burgess
- Food Safety Department, Teagasc Food Research Centre, Ashtown, Dublin 15, Ireland
| | | | - Frédérique Chaucheyras-Durand
- Université Clermont Auvergne, INRAE, MEDiS, F-63000 Clermont-Ferrand, France.,Lallemand Animal Nutrition SAS, F-31702 Blagnac Cedex, France
| | - Mickaël Desvaux
- Université Clermont Auvergne, INRAE, MEDiS, F-63000 Clermont-Ferrand, France
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5
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Meza-Segura M, Zaidi MB, Vera-Ponce de León A, Moran-Garcia N, Martinez-Romero E, Nataro JP, Estrada-Garcia T. New Insights Into DAEC and EAEC Pathogenesis and Phylogeny. Front Cell Infect Microbiol 2020; 10:572951. [PMID: 33178627 PMCID: PMC7593697 DOI: 10.3389/fcimb.2020.572951] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Accepted: 09/09/2020] [Indexed: 11/13/2022] Open
Abstract
Diarrheagenic E. coli can be separated into six distinct pathotypes, with enteroaggregative (EAEC) and diffusely-adherent E. coli (DAEC) among the least characterized. To gain additional insights into these two pathotypes we performed whole genome sequencing of ten DAEC, nine EAEC strains, isolated from Mexican children with diarrhea, and one EAEC plus one commensal E. coli strains isolated from an adult with diarrhea and a healthy child, respectively. These genome sequences were compared to 85 E. coli genomes available in public databases. The EAEC and DAEC strains segregated into multiple different clades; however, six clades were heavily or exclusively comprised of EAEC and DAEC strains, suggesting a phylogenetic relationship between these two pathotypes. EAEC strains harbored the typical virulence factors under control of the activator AggR, but also several toxins, bacteriocins, and other virulence factors. DAEC strains harbored several iron-scavenging systems, toxins, adhesins, and complement resistance or Immune system evasion factors that suggest a pathogenic paradigm for this poorly understood pathotype. Several virulence factors for both EAEC and DAEC were associated with clinical presentations, not only suggesting the importance of these factors, but also potentially indicating opportunities for intervention. Our studies provide new insights into two distinct but related diarrheagenic organisms.
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Affiliation(s)
- Mario Meza-Segura
- Molecular Biomedicine Department, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Mexico City, Mexico
| | - Mussaret B Zaidi
- Infectious Diseases Research Unit, Hospital General O'Horan, Mérida, Mexico.,Department of Epidemiology and Biostatistics, Michigan State University, Lansing, MI, United States
| | | | - Nadia Moran-Garcia
- Molecular Biomedicine Department, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Mexico City, Mexico
| | | | - James P Nataro
- Department of Pediatrics, University of Virginia, Charlottesville, VI, United States
| | - Teresa Estrada-Garcia
- Molecular Biomedicine Department, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Mexico City, Mexico
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6
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Govindarajan DK, Viswalingam N, Meganathan Y, Kandaswamy K. Adherence patterns of Escherichia coli in the intestine and its role in pathogenesis. MEDICINE IN MICROECOLOGY 2020. [DOI: 10.1016/j.medmic.2020.100025] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
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Andreozzi E, Uhlich GA. PchE Regulation of Escherichia coli O157:H7 Flagella, Controlling the Transition to Host Cell Attachment. Int J Mol Sci 2020; 21:ijms21134592. [PMID: 32605187 PMCID: PMC7369912 DOI: 10.3390/ijms21134592] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2020] [Revised: 06/24/2020] [Accepted: 06/26/2020] [Indexed: 11/16/2022] Open
Abstract
Shiga toxins and intimate adhesion controlled by the locus of enterocyte effacement are major enterohemorrhagic Escherichia coli (EHEC) virulence factors. Curli fimbriae also contribute to cell adhesion and are essential biofilm components. The transcriptional regulator PchE represses the expression of curli and their adhesion to HEp-2 cells. Past studies indicate that pchE also represses additional adhesins that contribute to HEp-2 cell attachment. In this study, we tested for pchE regulation of several tissue adhesins and their regulators. Three adhesin-encoding genes (eae, lpfA1, fliC) and four master regulators (csgD, stpA, ler, flhDC) were controlled by pchE. pchE over-expression strongly up-regulated fliC but the marked flagella induction reduced the attachment of O157:H7 clinical isolate PA20 to HEp-2 cells, indicating that flagella were blocking cell attachments rather than functioning as an adhesin. Chemotaxis, motor, structural, and regulatory genes in the flagellar operons were all increased by pchE expression, as was PA20 motility. This study identifies new members in the pchE regulon and shows that pchE stimulates flagellar motility while repressing cell adhesion, likely to support EHEC movement to the intestinal surface early in infection. However, induced or inappropriate pchE-dependent flagellar expression could block cell attachments later during disease progression.
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8
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Elpers L, Hensel M. Expression and Functional Characterization of Various Chaperon-Usher Fimbriae, Curli Fimbriae, and Type 4 Pili of Enterohemorrhagic Escherichia coli O157:H7 Sakai. Front Microbiol 2020; 11:378. [PMID: 32265855 PMCID: PMC7098969 DOI: 10.3389/fmicb.2020.00378] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2019] [Accepted: 02/20/2020] [Indexed: 11/25/2022] Open
Abstract
Enterohemorrhagic Escherichia coli (EHEC) is a highly pathogenic strain leading to hemorrhagic colitis and to the hemolytic-uremic syndrome (HUS) in humans. The mechanisms by which pathogenic E. coli infect and colonize humans leading to the typical disease pattern are in focus of many investigations. The adhesion of EHEC to epithelial cells by the coordinated translocation of receptor Tir and surface expression of corresponding adhesin intimin is a key event in host–pathogen-interaction. However, less is known about other adhesins encoded by EHEC, especially about the complex set of fimbrial adhesins varying among various serotypes. Here, we investigate EHEC serotype O157:H7 strain Sakai possessing at least 16 putative fimbrial gene clusters. Using a synthetic heterologous expression system in a non-pathogenic E. coli strain, a subset of 6 gene clusters for fimbrial adhesins was analyzed. We were able to visualize surface expression of two γ1 class fimbriae (Fim and Ycb), two γ4 class fimbriae (Yad and Yeh), and two fimbrial adhesins which are assembled by the nucleation/precipitation pathway (Curli fimbriae), and by a type 2 secretion system (type 4 pili). Further, we elucidated the impact of these fimbrial adhesins in adhesion to various epithelial cells lines (HeLa, MDCK, and CaCo2), and the contribution on biofilm formation. We demonstrate the ultrastructure of Fim fimbriae and Yad fimbriae of EHEC Sakai, and Yeh fimbriae of E. coli in general. The involvement of Fim fimbriae of EHEC Sakai to adhesion to various epithelial cell lines, and contribution to biofilm formation is reported here. Our approach provides first ultrastructural and functional data for novel EHEC adhesins, and enables further understanding of the involvement of fimbrial adhesins in pathogenesis of EHEC Sakai.
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Affiliation(s)
- Laura Elpers
- Abteilung Mikrobiologie, Osnabrück University, Osnabrück, Germany
| | - Michael Hensel
- Abteilung Mikrobiologie, Osnabrück University, Osnabrück, Germany.,CellNanOs - Center of Cellular Nanoanalytics Osnabrück, Osnabrück University, Osnabrück, Germany
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9
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Wu Y, Hu Q, Dehinwal R, Rakov AV, Grams N, Clemens EC, Hofmann J, Okeke IN, Schifferli DM. The Not so Good, the Bad and the Ugly: Differential Bacterial Adhesion and Invasion Mediated by Salmonella PagN Allelic Variants. Microorganisms 2020; 8:microorganisms8040489. [PMID: 32235448 PMCID: PMC7232170 DOI: 10.3390/microorganisms8040489] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Revised: 03/24/2020] [Accepted: 03/28/2020] [Indexed: 11/21/2022] Open
Abstract
While advances in genomic sequencing have highlighted significant strain variability between and within Salmonella serovars, only a few protein variants have been directly related to evolutionary adaptation for survival, such as host specificity or differential virulence. The current study investigated whether allelic variation of the Salmonella adhesin/invasin PagN influences bacterial interaction with their receptors. The Salmonella enterica, subspecies enterica serovar Typhi (S. Typhi) allelic variant of PagN was found to bind significantly better to different enterocytes as well as to the extracellular matrix protein laminin than did the major Salmonella enterica, subspecies enterica serovar Typhimurium (S. Typhimurium) allele. The two alleles differed at amino acid residues 49 and 109 in two of the four predicted PagN surface loops, and residue substitution analysis revealed that a glutamic acid at residue 49 increased the adhesive and invasive properties of S. Typhi PagN. PagN sequence comparisons from 542 Salmonella strains for six representative S. enterica serovars and S. diarizonae further supported the role of glutamic acid at residues 49 and 109 in optimizing adhesion to cells and laminin, as well as for cell invasion. In summary, this study characterized unique residues in allelic variants of a virulence factor that participates in the colonization and invasive properties of different Salmonella stains, subspecies and serovars.
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Affiliation(s)
- Yanping Wu
- Department of Pathobiology, University of Pennsylvania, School of Veterinary Medicine, Philadelphia, PA 19104, USA; (Y.W.); (R.D.); (A.V.R.); (N.G.)
- College of Animal Science and Technology, College of Veterinary Medicine, Zhejiang Agriculture and Forestry University, Hangzhou 311300, China
| | - Qiaoyun Hu
- Department of Pathobiology, University of Pennsylvania, School of Veterinary Medicine, Philadelphia, PA 19104, USA; (Y.W.); (R.D.); (A.V.R.); (N.G.)
| | - Ruchika Dehinwal
- Department of Pathobiology, University of Pennsylvania, School of Veterinary Medicine, Philadelphia, PA 19104, USA; (Y.W.); (R.D.); (A.V.R.); (N.G.)
| | - Alexey V. Rakov
- Department of Pathobiology, University of Pennsylvania, School of Veterinary Medicine, Philadelphia, PA 19104, USA; (Y.W.); (R.D.); (A.V.R.); (N.G.)
| | - Nicholas Grams
- Department of Pathobiology, University of Pennsylvania, School of Veterinary Medicine, Philadelphia, PA 19104, USA; (Y.W.); (R.D.); (A.V.R.); (N.G.)
| | - Erin C. Clemens
- Department of Biology, Haverford College, Haverford, PA 19041, USA; (E.C.C.); (J.H.); (I.N.O.)
| | - Jennifer Hofmann
- Department of Biology, Haverford College, Haverford, PA 19041, USA; (E.C.C.); (J.H.); (I.N.O.)
| | - Iruka N. Okeke
- Department of Biology, Haverford College, Haverford, PA 19041, USA; (E.C.C.); (J.H.); (I.N.O.)
- Department of Pharmaceutical Microbiology, Faculty of Pharmacy, University of Ibadan, Ibadan 200284, Oyo State, Nigeria
| | - Dieter M. Schifferli
- Department of Pathobiology, University of Pennsylvania, School of Veterinary Medicine, Philadelphia, PA 19104, USA; (Y.W.); (R.D.); (A.V.R.); (N.G.)
- Correspondence:
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10
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OXA-181-Producing Extraintestinal Pathogenic Escherichia coli Sequence Type 410 Isolated from a Dog in Portugal. Antimicrob Agents Chemother 2020; 64:AAC.02298-19. [PMID: 31964797 DOI: 10.1128/aac.02298-19] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2019] [Accepted: 01/17/2020] [Indexed: 12/18/2022] Open
Abstract
Two multidrug-resistant and carbapenemase-producing Escherichia coli clones of sequence type 410 were isolated from fecal samples of a dog with skin infection on admission to an animal hospital in Portugal and 1 month after discharge. Whole-genome sequencing revealed a 126,409-bp Col156/IncFIA/IncFII multidrug resistance plasmid and a 51,479-bp IncX3 bla OXA-181-containing plasmid. The chromosome and plasmids carried virulence genes characteristic for uropathogenic E. coli, indicating that dogs may carry multidrug-resistant E. coli isolates related to those causing urinary tract infections in humans.
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11
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Munhoz DD, Nara JM, Freitas NC, Moraes CTP, Nunes KO, Yamamoto BB, Vasconcellos FM, Martínez-Laguna Y, Girón JA, Martins FH, Abe CM, Elias WP, Piazza RMF. Distribution of Major Pilin Subunit Genes Among Atypical Enteropathogenic Escherichia coli and Influence of Growth Media on Expression of the ecp Operon. Front Microbiol 2018; 9:942. [PMID: 29867850 PMCID: PMC5962669 DOI: 10.3389/fmicb.2018.00942] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2017] [Accepted: 04/23/2018] [Indexed: 12/15/2022] Open
Abstract
Atypical enteropathogenic Escherichia coli (aEPEC) strains are unable to produce the bundle-forming pilus (BFP), which is responsible for the localized adherence pattern, a characteristic of the pathogenicity of typical EPEC strains. The lack of BFP in aEPEC strains suggests that other fimbrial or non-fimbrial adhesins are involved in their adhesion to the host cells. The aim of this study was to investigate the distribution of major subunit fimbrial genes known to be important adherence factors produced by several E. coli pathotypes in a collection of 72 aEPEC strains. Our results demonstrate that a high percentage (94–100%) of aEPEC strains harbored ecpA, fimA, hcpA, and lpfA fimbrial genes. Other fimbrial genes including pilS, pilV, sfpA, daaC, papA, and sfa were detected at lower frequencies (1–8%). Genes encoding fimbrial subunits, which are characteristic of enteroaggregative E. coli or enterotoxigenic E. coli were not found. No correlation was found between fimbrial gene profiles and adherence phenotypes. Since all aEPEC strains contained ecpA, the major pilin gene of the E. coli common pilus (ECP), a subset of ecpA+ strains was analyzed for transcription of ecpRABCDE and production of ECP upon growth in three different culture conditions at 37°C. Transcription of ecpRABCDE occurred in all conditions; however, ECP production was medium dependent. In all, the data suggest that aEPEC strains are highly heterogeneous in terms of their fimbrial gene profiles. Despite lacking BFP production, other mechanisms of cell adherence exist in aEPEC strains to ensure host colonization, e.g., mediated by other prevalent pili such as ECP. Moreover, the production of ECP by aEPEC strains might be influenced by yet unknown post-transcriptional factors.
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Affiliation(s)
| | - Júlia M Nara
- Laboratório de Bacteriologia, Instituto Butantan, São Paulo, Brazil
| | | | | | - Kamila O Nunes
- Laboratório de Bacteriologia, Instituto Butantan, São Paulo, Brazil
| | - Bruno B Yamamoto
- Laboratório de Bacteriologia, Instituto Butantan, São Paulo, Brazil
| | | | | | - Jorge A Girón
- Centro de Detección Biomolecular, Benemérita Universidad Autónoma de Puebla, Puebla, Mexico
| | | | - Cecilia M Abe
- Laboratório de Bacteriologia, Instituto Butantan, São Paulo, Brazil
| | - Waldir P Elias
- Laboratório de Bacteriologia, Instituto Butantan, São Paulo, Brazil
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12
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Gonzalez E, Pitre FE, Pagé AP, Marleau J, Guidi Nissim W, St-Arnaud M, Labrecque M, Joly S, Yergeau E, Brereton NJB. Trees, fungi and bacteria: tripartite metatranscriptomics of a root microbiome responding to soil contamination. MICROBIOME 2018; 6:53. [PMID: 29562928 PMCID: PMC5863371 DOI: 10.1186/s40168-018-0432-5] [Citation(s) in RCA: 63] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2016] [Accepted: 03/02/2018] [Indexed: 05/05/2023]
Abstract
BACKGROUND One method for rejuvenating land polluted with anthropogenic contaminants is through phytoremediation, the reclamation of land through the cultivation of specific crops. The capacity for phytoremediation crops, such as Salix spp., to tolerate and even flourish in contaminated soils relies on a highly complex and predominantly cryptic interacting community of microbial life. METHODS Here, Illumina HiSeq 2500 sequencing and de novo transcriptome assembly were used to observe gene expression in washed Salix purpurea cv. 'Fish Creek' roots from trees pot grown in petroleum hydrocarbon-contaminated or non-contaminated soil. All 189,849 assembled contigs were annotated without a priori assumption as to sequence origin and differential expression was assessed. RESULTS The 839 contigs differentially expressed (DE) and annotated from S. purpurea revealed substantial increases in transcripts encoding abiotic stress response equipment, such as glutathione S-transferases, in roots of contaminated trees as well as the hallmarks of fungal interaction, such as SWEET2 (Sugars Will Eventually Be Exported Transporter). A total of 8252 DE transcripts were fungal in origin, with contamination conditions resulting in a community shift from Ascomycota to Basidiomycota genera. In response to contamination, 1745 Basidiomycota transcripts increased in abundance (the majority uniquely expressed in contaminated soil) including major monosaccharide transporter MST1, primary cell wall and lamella CAZy enzymes, and an ectomycorrhiza-upregulated exo-β-1,3-glucanase (GH5). Additionally, 639 DE polycistronic transcripts from an uncharacterised Enterobacteriaceae species were uniformly in higher abundance in contamination conditions and comprised a wide spectrum of genes cryptic under laboratory conditions but considered putatively involved in eukaryotic interaction, biofilm formation and dioxygenase hydrocarbon degradation. CONCLUSIONS Fungal gene expression, representing the majority of contigs assembled, suggests out-competition of white rot Ascomycota genera (dominated by Pyronema), a sometimes ectomycorrhizal (ECM) Ascomycota (Tuber) and ECM Basidiomycota (Hebeloma) by a poorly characterised putative ECM Basidiomycota due to contamination. Root and fungal expression involved transcripts encoding carbohydrate/amino acid (C/N) dialogue whereas bacterial gene expression included the apparatus necessary for biofilm interaction and direct reduction of contamination stress, a potential bacterial currency for a role in tripartite mutualism. Unmistakable within the metatranscriptome is the degree to which the landscape of rhizospheric biology, particularly the important but predominantly uncharacterised fungal genetics, is yet to be discovered.
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Affiliation(s)
- E Gonzalez
- Canadian Center for Computational Genomics, McGill University and Genome Quebec Innovation Center, Montréal, H3A 1A4, Canada
- Department of Human Genetics, McGill University, Montreal, H3A 1B1, Canada
| | - F E Pitre
- Institut de recherche en biologie végétale, University of Montreal, Montreal, QC, H1X 2B2, Canada
- Montreal Botanical Garden, Montreal, QC, H1X 2B2, Canada
| | - A P Pagé
- Aquatic and Crop Resource Development (ACRD), National Research Council Canada, Montréal, QC, H4P 2R2, Canada
| | - J Marleau
- Institut de recherche en biologie végétale, University of Montreal, Montreal, QC, H1X 2B2, Canada
| | - W Guidi Nissim
- Department of Agri-food and Environmental Science, University of Florence, Viale delle Idee, Sesto Fiorentino, FI, Italy
| | - M St-Arnaud
- Institut de recherche en biologie végétale, University of Montreal, Montreal, QC, H1X 2B2, Canada
- Montreal Botanical Garden, Montreal, QC, H1X 2B2, Canada
| | - M Labrecque
- Institut de recherche en biologie végétale, University of Montreal, Montreal, QC, H1X 2B2, Canada
- Montreal Botanical Garden, Montreal, QC, H1X 2B2, Canada
| | - S Joly
- Institut de recherche en biologie végétale, University of Montreal, Montreal, QC, H1X 2B2, Canada
- Montreal Botanical Garden, Montreal, QC, H1X 2B2, Canada
| | - E Yergeau
- Institut National de la Recherche Scientifique, Centre INRS-Institut Armand-Frappier, Laval, QC, Canada
| | - N J B Brereton
- Institut de recherche en biologie végétale, University of Montreal, Montreal, QC, H1X 2B2, Canada.
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13
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Le Bihan G, Sicard JF, Garneau P, Bernalier-Donadille A, Gobert AP, Garrivier A, Martin C, Hay AG, Beaudry F, Harel J, Jubelin G. The NAG Sensor NagC Regulates LEE Gene Expression and Contributes to Gut Colonization by Escherichia coli O157:H7. Front Cell Infect Microbiol 2017; 7:134. [PMID: 28484684 PMCID: PMC5401889 DOI: 10.3389/fcimb.2017.00134] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2017] [Accepted: 03/31/2017] [Indexed: 11/16/2022] Open
Abstract
Enterohemorrhagic Escherichia coli (EHEC) O157:H7 are human pathogens responsible for bloody diarrhea and renal failures. EHEC employ a type 3 secretion system to attach directly to the human colonic epithelium. This structure is encoded by the locus of enterocyte effacement (LEE) whose expression is regulated in response to specific nutrients. In this study, we show that the mucin-derived sugars N-acetylglucosamine (NAG) and N-acetylneuraminic acid (NANA) inhibit EHEC adhesion to epithelial cells through down-regulation of LEE expression. The effect of NAG and NANA is dependent on NagC, a transcriptional repressor of the NAG catabolism in E. coli. We show that NagC is an activator of the LEE1 operon and a critical regulator for the colonization of mice intestine by EHEC. Finally, we demonstrate that NAG and NANA as well as the metabolic activity of Bacteroides thetaiotaomicron affect the in vivo fitness of EHEC in a NagC-dependent manner. This study highlights the role of NagC in coordinating metabolism and LEE expression in EHEC and in promoting EHEC colonization in vivo.
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Affiliation(s)
- Guillaume Le Bihan
- Faculté de Médecine Vétérinaire, Centre de Recherche en Infectiologie Porcine et Aviaire, Université de MontréalSaint-Hyacinthe, QC, Canada
| | - Jean-Félix Sicard
- Faculté de Médecine Vétérinaire, Centre de Recherche en Infectiologie Porcine et Aviaire, Université de MontréalSaint-Hyacinthe, QC, Canada
| | - Philippe Garneau
- Faculté de Médecine Vétérinaire, Centre de Recherche en Infectiologie Porcine et Aviaire, Université de MontréalSaint-Hyacinthe, QC, Canada
| | | | - Alain P Gobert
- INRA, Université Clermont Auvergne, MEDISClermont-Ferrand, France
| | - Annie Garrivier
- INRA, Université Clermont Auvergne, MEDISClermont-Ferrand, France
| | - Christine Martin
- INRA, Université Clermont Auvergne, MEDISClermont-Ferrand, France
| | - Anthony G Hay
- Department of Microbiology, Cornell UniversityIthaca, NY, USA
| | - Francis Beaudry
- Groupe de Recherche en Pharmacologie Animal du Québec, Département de Biomédecine Vétérinaire, Faculté de Médecine Vétérinaire, Université de MontréalSaint-Hyacinthe, QC, Canada
| | - Josée Harel
- Faculté de Médecine Vétérinaire, Centre de Recherche en Infectiologie Porcine et Aviaire, Université de MontréalSaint-Hyacinthe, QC, Canada
| | - Grégory Jubelin
- INRA, Université Clermont Auvergne, MEDISClermont-Ferrand, France
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14
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Virulence traits and different nle profiles in cattle and human verotoxin-producing Escherichia coli O157:H7 strains from Argentina. Microb Pathog 2017; 102:102-108. [DOI: 10.1016/j.micpath.2016.11.022] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2016] [Revised: 10/28/2016] [Accepted: 11/29/2016] [Indexed: 12/22/2022]
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15
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Larsonneur F, Martin FA, Mallet A, Martinez-Gil M, Semetey V, Ghigo JM, Beloin C. Functional analysis of Escherichia coli Yad fimbriae reveals their potential role in environmental persistence. Environ Microbiol 2016; 18:5228-5248. [PMID: 27696649 DOI: 10.1111/1462-2920.13559] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Initial adhesion of bacterial cells to surfaces or host tissues is a key step in colonisation and biofilm formation processes, and is mediated by cell surface appendages. It was previously demonstrated that Escherichia coli K-12 possesses an arsenal of silenced chaperone-usher fimbriae that were functional when constitutively expressed. Among them, production of prevalent Yad fimbriae induces adhesion to abiotic surfaces. Functional characterisation of Yad fimbriae were undertook, and YadN was identified as the most abundant and potential major pilin, and YadC as the potential tip-protein of Yad fimbriae. It was showed that Yad production participates to binding of E. coli K-12 to human eukaryotic cells (Caco-2) and inhibits macrophage phagocytosis, but also enhances E. coli K-12 binding to xylose, a major component of the plant cell wall, through its tip-lectin YadC. Consistently, it was demonstrated that Yad production provides E. coli with a competitive advantage in colonising corn seed rhizospheres. The latter phenotype is correlated with induction of Yad expression at temperatures below 37°C, and under anaerobic conditions, through a complex regulatory network. Taken together, these results suggest that Yad fimbriae are versatile adhesins that beyond potential capacities to modulate host-pathogen interactions might contribute to E. coli environmental persistence.
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Affiliation(s)
- Fanny Larsonneur
- Institut Pasteur, Unité de Génétique des Biofilms, 28 rue du Dr. Roux 75724, Paris cedex, France.,Ecole Doctorale Bio Sorbonne Paris Cité (BioSPC), Université Paris Diderot, Cellule Pasteur, rue du Dr. Roux 75724, Paris cedex, France
| | - Fernando A Martin
- Institut Pasteur, Unité de Génétique des Biofilms, 28 rue du Dr. Roux 75724, Paris cedex, France
| | - Adeline Mallet
- Institut Pasteur, Ultrapole, 28 rue du Dr. Roux 75724, Paris cedex, France
| | - Marta Martinez-Gil
- Institut Pasteur, Unité de Génétique des Biofilms, 28 rue du Dr. Roux 75724, Paris cedex, France
| | - Vincent Semetey
- PSL Research University, Chimie ParisTech - CNRS, Institut de Recherche de Chimie Paris, Paris, 75005, France
| | - Jean-Marc Ghigo
- Institut Pasteur, Unité de Génétique des Biofilms, 28 rue du Dr. Roux 75724, Paris cedex, France
| | - Christophe Beloin
- Institut Pasteur, Unité de Génétique des Biofilms, 28 rue du Dr. Roux 75724, Paris cedex, France
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16
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Monteiro R, Ageorges V, Rojas-Lopez M, Schmidt H, Weiss A, Bertin Y, Forano E, Jubelin G, Henderson IR, Livrelli V, Gobert AP, Rosini R, Soriani M, Desvaux M. A secretome view of colonisation factors in Shiga toxin-encodingEscherichia coli(STEC): from enterohaemorrhagicE. coli(EHEC) to related enteropathotypes. FEMS Microbiol Lett 2016; 363:fnw179. [DOI: 10.1093/femsle/fnw179] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/18/2016] [Indexed: 12/25/2022] Open
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17
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Hsiao FSH, Sutandy FXR, Syu GD, Chen YW, Lin JM, Chen CS. Systematic protein interactome analysis of glycosaminoglycans revealed YcbS as a novel bacterial virulence factor. Sci Rep 2016; 6:28425. [PMID: 27323865 PMCID: PMC4914927 DOI: 10.1038/srep28425] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2015] [Accepted: 06/06/2016] [Indexed: 11/09/2022] Open
Abstract
Microbial pathogens have evolved several strategies for interacting with host cell components, such as glycosaminoglycans (GAGs). Some microbial proteins involved in host-GAG binding have been described; however, a systematic study on microbial proteome-mammalian GAG interactions has not been conducted. Here, we used Escherichia coli proteome chips to probe four typical mammalian GAGs, heparin, heparan sulphate (HS), chondroitin sulphate B (CSB), and chondroitin sulphate C (CSC), and identified 185 heparin-, 62 HS-, 98 CSB-, and 101 CSC-interacting proteins. Bioinformatics analyses revealed the unique functions of heparin- and HS-specific interacting proteins in glycine, serine, and threonine metabolism. Among all the GAG-interacting proteins, three were outer membrane proteins (MbhA, YcbS, and YmgH). Invasion assays confirmed that mutant E. coli lacking ycbS could not invade the epithelial cells. Introducing plasmid carrying ycbS complemented the invading defects at ycbS lacking E. coli mutant, that can be further improved by overexpressing ycbS. Preblocking epithelial cells with YcbS reduced the percentage of E. coli invasions. Moreover, we observed that whole components of the ycb operon were crucial for invasion. The displacement assay revealed that YcbS binds to the laminin-binding site of heparin and might affect the host extracellular matrix structure by displacing heparin from laminin.
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Affiliation(s)
- Felix Shih-Hsiang Hsiao
- Graduate Institute of Systems Biology and Bioinformatics, National Central University, Jongli District, Taoyuan City 32001, Taiwan
- Department of Biomedical Science and Engineering, National Central University, Jongli District, Taoyuan City 32001, Taiwan
| | - FX Reymond Sutandy
- Graduate Institute of Systems Biology and Bioinformatics, National Central University, Jongli District, Taoyuan City 32001, Taiwan
- Department of Biomedical Science and Engineering, National Central University, Jongli District, Taoyuan City 32001, Taiwan
| | - Guan-Da Syu
- Graduate Institute of Systems Biology and Bioinformatics, National Central University, Jongli District, Taoyuan City 32001, Taiwan
- Department of Biomedical Science and Engineering, National Central University, Jongli District, Taoyuan City 32001, Taiwan
| | - Yi-Wen Chen
- Graduate Institute of Systems Biology and Bioinformatics, National Central University, Jongli District, Taoyuan City 32001, Taiwan
- Department of Biomedical Science and Engineering, National Central University, Jongli District, Taoyuan City 32001, Taiwan
| | - Jun-Mu Lin
- Graduate Institute of Systems Biology and Bioinformatics, National Central University, Jongli District, Taoyuan City 32001, Taiwan
- Department of Biomedical Science and Engineering, National Central University, Jongli District, Taoyuan City 32001, Taiwan
| | - Chien-Sheng Chen
- Graduate Institute of Systems Biology and Bioinformatics, National Central University, Jongli District, Taoyuan City 32001, Taiwan
- Department of Biomedical Science and Engineering, National Central University, Jongli District, Taoyuan City 32001, Taiwan
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18
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Abstract
Adhesins are a group of proteins in enterohemorrhagic Escherichia coli (EHEC) that are involved in the attachment or colonization of this pathogen to abiotic (plastic or steel) and biological surfaces, such as those found in bovine and human intestines. This review provides the most up-to-date information on these essential adhesion factors, summarizing important historical discoveries and analyzing the current and future state of this research. In doing so, the proteins intimin and Tir are discussed in depth, especially regarding their role in the development of attaching and effacing lesions and in EHEC virulence. Further, a series of fimbrial proteins (Lpf1, Lpf2, curli, ECP, F9, ELF, Sfp, HCP, and type 1 fimbriae) are also described, emphasizing their various contributions to adherence and colonization of different surfaces and their potential use as genetic markers in detection and classification of different EHEC serotypes. This review also discusses the role of several autotransporter proteins (EhaA-D, EspP, Saa and Sab, and Cah), as well as other proteins associated with adherence, such as flagella, EibG, Iha, and OmpA. While these proteins have all been studied to varying degrees, all of the adhesins summarized in this chapter have been linked to different stages of the EHEC life cycle, making them good targets for the development of more effective diagnostics and therapeutics.
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Affiliation(s)
- Brian D. McWilliams
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, Texas, 77555. USA
| | - Alfredo G. Torres
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, Texas, 77555. USA
- Department of Pathology and Sealy Center for Vaccine Development, University of Texas Medical Branch, Galveston, Texas, 77555. USA
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19
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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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20
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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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21
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Jaglic Z, Desvaux M, Weiss A, Nesse LL, Meyer RL, Demnerova K, Schmidt H, Giaouris E, Sipailiene A, Teixeira P, Kačániová M, Riedel CU, Knøchel S. Surface adhesins and exopolymers of selected foodborne pathogens. MICROBIOLOGY-SGM 2014; 160:2561-2582. [PMID: 25217529 DOI: 10.1099/mic.0.075887-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The ability of bacteria to bind different compounds and to adhere to biotic and abiotic surfaces provides them with a range of advantages, such as colonization of various tissues, internalization, avoidance of an immune response, and survival and persistence in the environment. A variety of bacterial surface structures are involved in this process and these promote bacterial adhesion in a more or less specific manner. In this review, we will focus on those surface adhesins and exopolymers in selected foodborne pathogens that are involved mainly in primary adhesion. Their role in biofilm development will also be considered when appropriate. Both the clinical impact and the implications for food safety of such adhesion will be discussed.
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Affiliation(s)
- Zoran Jaglic
- Veterinary Research Institute, Brno, Czech Republic
| | - Mickaël Desvaux
- INRA, UR454 Microbiologie, F-63122 Saint-Genès Champanelle, France
| | - Agnes Weiss
- Department of Food Microbiology, Institute of Food Science and Biotechnology, University of Hohenheim, Garbenstrasse 28, 70599 Stuttgart, Germany
| | | | - Rikke L Meyer
- Interdisciplinary Nanoscience Center (iNANO), Aarhus University, Gustav Wieds Vej 14, DK-8000 Aarhus C, Denmark
| | - Katerina Demnerova
- Institute of Chemical Technology, Faculty of Food and Biochemical Technology, Department of Biochemistry and Microbiology, Technicka 5, Prague, 166 28, Czech Republic
| | - Herbert Schmidt
- Department of Food Microbiology, Institute of Food Science and Biotechnology, University of Hohenheim, Garbenstrasse 28, 70599 Stuttgart, Germany
| | - Efstathios Giaouris
- Department of Food Science and Nutrition, Faculty of the Environment, University of the Aegean, 81400 Myrina, Lemnos Island, Greece
| | | | - Pilar Teixeira
- CEB - Centre of Biological Engineering, University of Minho, Braga, Portugal
| | | | - Christian U Riedel
- Institute of Microbiology and Biotechnology, University of Ulm, Ulm, Germany
| | - Susanne Knøchel
- Department of Food Science, University of Copenhagen, Rolighedsvej 30, Frederiksberg C 1958, Denmark
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22
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Abstract
ABSTRACT
Coordinated expression of enterohemorrhagic
Escherichia coli
virulence genes enables the bacterium to cause hemorrhagic colitis and the complication known as hemolytic-uremic syndrome. Horizontally acquired genes and those common to
E. coli
contribute to the disease process, and increased virulence gene expression is correlated with more severe disease in humans. Researchers have gained considerable knowledge about how the type III secretion system, secreted effectors, adhesin molecules, and the Shiga toxins are regulated by environmental signals and multiple genetic pathways. Also emergent from the data is an understanding of how enterohemorrhagic
E. coli
regulates response to acid stress, the role of flagellar motility, and how passage through the human host and bovine intestinal tract causes disease and supports carriage in the cattle reservoir, respectively. Particularly exciting areas of discovery include data suggesting how expression of the myriad effectors is coordinately regulated with their cognate type III secretion system and how virulence is correlated with bacterial metabolism and gut physiology.
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Chagnot C, Caccia N, Loukiadis E, Ganet S, Durand A, Bertin Y, Talon R, Astruc T, Desvaux M. Colonization of the meat extracellular matrix proteins by O157 and non-O157 enterohemorrhagic Escherichia coli. Int J Food Microbiol 2014; 188:92-8. [PMID: 25090606 DOI: 10.1016/j.ijfoodmicro.2014.07.016] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2014] [Revised: 05/27/2014] [Accepted: 07/15/2014] [Indexed: 11/28/2022]
Abstract
Enterohemorrhagic Escherichia coli (EHEC) are anthropozoonotic agents that range third among food-borne pathogens respective to their incidence and dangerousness in the European Union. EHEC are Shiga-toxin producing E. coli (STEC) responsible for foodborne poisoning mainly incriminated to the consumption of contaminated beef meat. Among the hundreds of STEC serotypes identified, EHEC mainly belong to O157:H7 but non-O157 can represent 20 to 70% of EHEC infections per year. Seven of those serogroups are especially of high-risk for human health, i.e. O26, O45, O103, O111, O121, O145 and O104. While meat can be contaminated all along the food processing chain, EHEC contamination essentially occurs at the dehiding stage of slaughtering. Investigating bacterial colonization to the skeletal-muscle extracellular matrix (ECM) proteins, it appeared that environmental factors influenced specific and non-specific bacterial adhesion of O157 and non-O157 EHEC as well as biofilm formation. Importantly, mechanical treatment (i.e. shaking, centrifugation, pipetting and vortexing) inhibited and biased the results of bacterial adhesion assay. Besides stressing the importance of the protocol to investigate bacterial adhesion to ECM proteins, this study demonstrated that the colonization abilities to ECM proteins vary among EHEC serogroups and should ultimately be taken into consideration to evaluate the risk of contamination for different types of food matrices.
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Affiliation(s)
- Caroline Chagnot
- INRA, UR454 Microbiologie, F-63122 Saint-Genès Champanelle, France; INRA, UR370 Qualité des Produits Animaux, F-63122 Saint-Genès Champanelle, France
| | - Nelly Caccia
- INRA, UR454 Microbiologie, F-63122 Saint-Genès Champanelle, France
| | - Estelle Loukiadis
- Université de Lyon, VetAgro Sup, LMAP Laboratory, National Reference Laboratory for E. coli (including STEC), F-69280 Marcy l'Etoile, France; Université de Lyon, UMR 5557 Ecologie Microbienne, Université Lyon 1, CNRS, VetAgro Sup, Research Group on Bacterial Opportunistic Pathogens and Environment, F-69622 Villeurbanne, France
| | - Sarah Ganet
- Université de Lyon, VetAgro Sup, LMAP Laboratory, National Reference Laboratory for E. coli (including STEC), F-69280 Marcy l'Etoile, France; Université de Lyon, UMR 5557 Ecologie Microbienne, Université Lyon 1, CNRS, VetAgro Sup, Research Group on Bacterial Opportunistic Pathogens and Environment, F-69622 Villeurbanne, France
| | - Alexandra Durand
- INRA, UR454 Microbiologie, F-63122 Saint-Genès Champanelle, France
| | - Yolande Bertin
- INRA, UR454 Microbiologie, F-63122 Saint-Genès Champanelle, France
| | - Régine Talon
- INRA, UR454 Microbiologie, F-63122 Saint-Genès Champanelle, France
| | - Thierry Astruc
- INRA, UR370 Qualité des Produits Animaux, F-63122 Saint-Genès Champanelle, France
| | - Mickaël Desvaux
- INRA, UR454 Microbiologie, F-63122 Saint-Genès Champanelle, France.
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24
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Ethanolamine and choline promote expression of putative and characterized fimbriae in enterohemorrhagic Escherichia coli O157:H7. Infect Immun 2013; 82:193-201. [PMID: 24126525 DOI: 10.1128/iai.00980-13] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Enterohemorrhagic Escherichia coli (EHEC) O157:H7 is an important food-borne pathogen responsible for disease outbreaks worldwide. In order to colonize the human gastrointestinal (GI) tract and cause disease, EHEC must be able to sense the host environment and promote expression of virulence genes essential for adherence. Ethanolamine (EA) is an important metabolite for EHEC in the GI tract, and EA is also a signal that EHEC uses to activate virulence traits. Here, we report that EA influenced EHEC adherence to epithelial cells and fimbrial gene expression. Quantitative reverse transcriptase PCR indicated that EA promoted the transcription of the genes in characterized and putative fimbrial operons. Moreover, putative fimbrial structures were produced by EHEC cells grown with EA but not in medium lacking EA. Additionally, we defined two previously uncharacterized EA-regulated fimbrial operons, loc10 and loc11. We also tested whether choline or serine, both of which are also components of cell membranes, activated fimbrial gene expression. In addition to EA, choline activated fimbrial gene expression in EHEC. These findings describe for the first time the transcription of several putative fimbrial loci in EHEC. Importantly, the biologically relevant molecules EA and choline, which are abundant in the GI tract, promoted expression of these fimbriae.
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25
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Croxen MA, Law RJ, Scholz R, Keeney KM, Wlodarska M, Finlay BB. Recent advances in understanding enteric pathogenic Escherichia coli. Clin Microbiol Rev 2013; 26:822-80. [PMID: 24092857 PMCID: PMC3811233 DOI: 10.1128/cmr.00022-13] [Citation(s) in RCA: 823] [Impact Index Per Article: 74.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Although Escherichia coli can be an innocuous resident of the gastrointestinal tract, it also has the pathogenic capacity to cause significant diarrheal and extraintestinal diseases. Pathogenic variants of E. coli (pathovars or pathotypes) cause much morbidity and mortality worldwide. Consequently, pathogenic E. coli is widely studied in humans, animals, food, and the environment. While there are many common features that these pathotypes employ to colonize the intestinal mucosa and cause disease, the course, onset, and complications vary significantly. Outbreaks are common in developed and developing countries, and they sometimes have fatal consequences. Many of these pathotypes are a major public health concern as they have low infectious doses and are transmitted through ubiquitous mediums, including food and water. The seriousness of pathogenic E. coli is exemplified by dedicated national and international surveillance programs that monitor and track outbreaks; unfortunately, this surveillance is often lacking in developing countries. While not all pathotypes carry the same public health profile, they all carry an enormous potential to cause disease and continue to present challenges to human health. This comprehensive review highlights recent advances in our understanding of the intestinal pathotypes of E. coli.
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26
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Cadona JS, Bustamante AV, Parma AE, Lucchesi PMA, Sanso AM. Distribution of additional virulence factors related to adhesion and toxicity in Shiga toxin-producing Escherichia coli isolated from raw products in Argentina. Lett Appl Microbiol 2013; 56:449-55. [PMID: 23488818 DOI: 10.1111/lam.12067] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2012] [Revised: 02/25/2013] [Accepted: 03/06/2013] [Indexed: 12/01/2022]
Abstract
UNLABELLED A total of 73 Shiga toxin-producing Escherichia coli (STEC) isolates, belonging to 25 serotypes and isolated from raw products in Argentina, were examined for the occurrence of genes responsible for bacterial adhesions to intestine, ehaA (EHEC autotransporter), lpfAO113 (long polar fimbriae), sab (STEC autotransporter [AT] contributing to biofilm formation), ecpA (E. coli common pilus), hcpA (haemorrhagic coli pilus), elfA (E. coli laminin-binding fimbriae), sfpA (sorbitol-fermenting EHEC O157 fimbriae plasmid-encoded) and of the toxigenic gene cdt-V (cytolethal distending toxin). Our study showed different adhesin profiles that are not linked to one specific serotype and that all analysed isolates possess, besides stx genes, some adherence genes. Several of the isolates contained also multiple toxin genes. The results of the present work alert the presence of genes coding for additional adhesins and cdt-V toxin in LEE-negative STEC strains that occur in foods, and this traits could increase their pathogenic potential. SIGNIFICANCE AND IMPACT OF THE STUDY Meat products are one of the main vehicles of Shiga toxin-producing E. coli, and the presence of genes coding for additional adhesins and toxins could increase their pathogenic potential. There is a need for a more detailed characterization of the strains in regard to these extra virulence factors.
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Affiliation(s)
- J S Cadona
- Laboratorio de Inmunoquímica y Biotecnología, CIVETAN-Facultad de Ciencias Veterinarias, Universidad Nacional del Centro de la Pcia. de Buenos Aires, Tandil, Argentina
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27
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The fimbrial protein FlfA from Gallibacterium anatis is a virulence factor and vaccine candidate. Infect Immun 2013; 81:1964-73. [PMID: 23509151 DOI: 10.1128/iai.00059-13] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The Gram-negative bacterium Gallibacterium anatis is a major cause of salpingitis and peritonitis in egg-laying chickens, leading to decreased egg production worldwide. Widespread multidrug resistance largely prevents treatment of this organism using traditional antimicrobial agents, while antigenic diversity hampers disease prevention by classical vaccines. Thus, insight into its pathogenesis and knowledge about important virulence factors is urgently required. A key event during the colonization and invasion of mucosal surfaces is adherence, and recently, at least three F17-like fimbrial gene clusters were identified in the genomes of several G. anatis strains. The objective of this study was to characterize the putative F17-like fimbrial subunit protein FlfA from G. anatis 12656-12 and determine its importance for virulence. In vitro expression and surface exposure of FlfA was demonstrated by flow cytometry and immunofluorescence microscopy. The predicted function of FlfA as a fimbrial subunit protein was confirmed by immunogold electron microscopy. An flfA deletion mutant (ΔflfA) was generated in G. anatis 12656-12, and importantly, this mutant was significantly attenuated in the natural chicken host. Furthermore, protection against G. anatis 12656-12 could be induced by immunizing chickens with recombinant FlfA. Finally, in vitro expression of FlfA homologs was observed in a genetically diverse set of G. anatis strains, suggesting the potential of FlfA as a serotype-independent vaccine candidate This is the first study describing a fimbrial subunit protein of G. anatis with a clear potential as a vaccine antigen.
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Hu J, Wang B, Fang X, Means WJ, McCormick RJ, Gomelsky M, Zhu MJ. c-di-GMP signaling regulates E. coli O157:H7 adhesion to colonic epithelium. Vet Microbiol 2013; 164:344-51. [PMID: 23528649 DOI: 10.1016/j.vetmic.2013.02.023] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2012] [Revised: 02/23/2013] [Accepted: 02/23/2013] [Indexed: 12/01/2022]
Abstract
Escherichia coli O157:H7 is an important foodborne pathogen that causes serious illness in humans at low infectious doses. The main source of infections is beef or greens contaminated with E. coli O157:H7 shed by cattle. Here we investigated the role of c-di-GMP-dependent signal transduction in cattle gut colonization of E. coli O157:H7. To manipulate intracellular c-di-GMP levels, we introduced into E. coli O157:H7 a c-di-GMP specific phosphodiesterase (PDE). Liquid chromatography tandem mass spectrometry analysis confirmed that in E. coli O157:H7, over-expression of PDE decreased c-di-GMP level. Consistent with the altered c-di-GMP level, PDE overexpression resulted in decreased biofilm formation in E. coli O157:H7. Furthermore, this diminished c-di-GMP levels reduced adhesion of E. coli O157:H7 to both cultured HT-29 cells and cattle colon explants. Consistently, mRNA levels of genes involved in adhesion were down-regulated including genes encoding E. coli common pili, long polar fimbriae 1, hemorrhagic coli pilus, as well as intimin and tir. We further observed decreased curli fimbriae synthesis in the strain with decreased c-di-GMP levels, which was supported by the reduction in the transcription of curli large subunit gene csgA and the curli expression regulator gene csgD. Genes for enterocyte effacement encoded regulator (Ler) and type III secretion system effectors, EspA and EspB, were also down-regulated. Collectively, data indicated that c-di-GMP signaling positively regulates E. coli O157:H7 intestinal epithelial cell and tissue colonization and expression of associated adhesion factors.
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Affiliation(s)
- Jia Hu
- Department of Animal Science, University of Wyoming, Laramie, WY 82071, USA
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Transcriptional regulation of the ecp operon by EcpR, IHF, and H-NS in attaching and effacing Escherichia coli. J Bacteriol 2012; 194:5020-33. [PMID: 22797761 DOI: 10.1128/jb.00915-12] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Enteropathogenic (EPEC) and enterohemorrhagic (EHEC) Escherichia coli are clinically important diarrheagenic pathogens that adhere to the intestinal epithelial surface. The E. coli common pili (ECP), or meningitis-associated and temperature-regulated (MAT) fimbriae, are ubiquitous among both commensal and pathogenic E. coli strains and play a role as colonization factors by promoting the interaction between bacteria and host epithelial cells and favoring interbacterial interactions in biofilm communities. The first gene of the ecp operon encodes EcpR (also known as MatA), a proposed regulatory protein containing a LuxR-like C-terminal helix-turn-helix (HTH) DNA-binding motif. In this work, we analyzed the transcriptional regulation of the ecp genes and the role of EcpR as a transcriptional regulator. EHEC and EPEC ecpR mutants produce less ECP, while plasmids expressing EcpR increase considerably the expression of EcpA and production of ECP. The ecp genes are transcribed as an operon from a promoter located 121 bp upstream of the start codon of ecpR. EcpR positively regulates this promoter by binding to two TTCCT boxes distantly located upstream of the ecp promoter, thus enhancing expression of downstream ecp genes, leading to ECP production. EcpR mutants in the putative HTH DNA-binding domain are no longer able to activate ecp expression or bind to the TTCCT boxes. EcpR-mediated activation is aided by integration host factor (IHF), which is essential for counteracting the repression exerted by histone-like nucleoid-structuring protein (H-NS) on the ecp promoter. This work demonstrates evidence about the interplay between a novel member of a diverse family of regulatory proteins and global regulators in the regulation of a fimbrial operon.
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Singh B, Fleury C, Jalalvand F, Riesbeck K. Human pathogens utilize host extracellular matrix proteins laminin and collagen for adhesion and invasion of the host. FEMS Microbiol Rev 2012; 36:1122-80. [PMID: 22537156 DOI: 10.1111/j.1574-6976.2012.00340.x] [Citation(s) in RCA: 199] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2011] [Revised: 02/08/2012] [Accepted: 03/29/2012] [Indexed: 01/11/2023] Open
Abstract
Laminin (Ln) and collagen are multifunctional glycoproteins that play an important role in cellular morphogenesis, cell signalling, tissue repair and cell migration. These proteins are ubiquitously present in tissues as a part of the basement membrane (BM), constitute a protective layer around blood capillaries and are included in the extracellular matrix (ECM). As a component of BMs, both Lns and collagen(s), thus function as major mechanical containment molecules that protect tissues from pathogens. Invasive pathogens breach the basal lamina and degrade ECM proteins of interstitial spaces and connective tissues using various ECM-degrading proteases or surface-bound plasminogen and matrix metalloproteinases recruited from the host. Most pathogens associated with the respiratory, gastrointestinal, or urogenital tracts, as well as with the central nervous system or the skin, have the capacity to bind and degrade Lns and collagen(s) in order to adhere to and invade host tissues. In this review, we focus on the adaptability of various pathogens to utilize these ECM proteins as enhancers for adhesion to host tissues or as a targets for degradation in order to breach the cellular barriers. The major pathogens discussed are Streptococcus, Staphylococcus, Pseudomonas, Salmonella, Yersinia, Treponema, Mycobacterium, Clostridium, Listeria, Porphyromonas and Haemophilus; Candida, Aspergillus, Pneumocystis, Cryptococcus and Coccidioides; Acanthamoeba, Trypanosoma and Trichomonas; retrovirus and papilloma virus.
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Affiliation(s)
- Birendra Singh
- Medical Microbiology, Department of Laboratory Medicine Malmö, Skåne University Hospital, Lund University, Malmö, Sweden
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Lloyd SJ, Ritchie JM, Rojas-Lopez M, Blumentritt CA, Popov VL, Greenwich JL, Waldor MK, Torres AG. A double, long polar fimbria mutant of Escherichia coli O157:H7 expresses Curli and exhibits reduced in vivo colonization. Infect Immun 2012; 80:914-20. [PMID: 22232190 PMCID: PMC3294650 DOI: 10.1128/iai.05945-11] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2011] [Accepted: 12/27/2011] [Indexed: 11/20/2022] Open
Abstract
Escherichia coli O157:H7 causes food and waterborne enteric infections that can result in hemorrhagic colitis and life-threatening hemolytic uremic syndrome. Intimate adherence of the bacteria to intestinal epithelial cells is mediated by intimin, but E. coli O157:H7 also possess several other putative adhesins, including curli and two operons that encode long polar fimbriae (Lpf). To assess the importance of Lpf for intestinal colonization, we performed competition experiments between E. coli O157:H7 and an isogenic ΔlpfA1 ΔlpfA2 double mutant in the infant rabbit model. The mutant was outcompeted in the ileum, cecum, and midcolon, suggesting that Lpf contributes to intestinal colonization. In contrast, the ΔlpfA1 ΔlpfA2 mutant showed increased adherence to colonic epithelial cells in vitro. Transmission electron microscopy revealed curli-like structures on the surface of the ΔlpfA1 ΔlpfA2 mutant, and the presence of curli was confirmed by Congo red binding, immunogold-labeling electron microscopy, immunoblotting, and quantitative real-time reverse transcription-PCR (qRT-PCR) measuring csgA expression. However, deletion of csgA, which encodes the major curli subunit, does not appear to affect intestinal colonization. In addition to suggesting that Lpf can contribute to EHEC intestinal colonization, our observations indicate that the regulatory pathways governing the expression of Lpf and curli are interdependent.
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Affiliation(s)
| | - Jennifer M. Ritchie
- Channing Laboratory, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts, USA
| | | | | | | | - Jennifer L. Greenwich
- Channing Laboratory, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts, USA
| | - Matthew K. Waldor
- Channing Laboratory, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts, USA
| | - Alfredo G. Torres
- Departments of Microbiology and Immunology
- Pathology
- Sealy Center for Vaccine Development, University of Texas Medical Branch, Galveston, Texas, USA
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Farfan MJ, Torres AG. Molecular mechanisms that mediate colonization of Shiga toxin-producing Escherichia coli strains. Infect Immun 2012; 80:903-13. [PMID: 22144484 PMCID: PMC3294676 DOI: 10.1128/iai.05907-11] [Citation(s) in RCA: 108] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Shiga toxin-producing Escherichia coli (STEC) is a group of pathogens which cause gastrointestinal disease in humans and have been associated with numerous food-borne outbreaks worldwide. The intimin adhesin has been considered for many years to be the only colonization factor in these strains. However, the rapid progress in whole-genome sequencing of different STEC serotypes has accelerated the discovery of other adhesins (fimbrial and afimbrial), which have emerged as important contributors to the intestinal colonization occurring during STEC infection. This review summarizes recent progress to identify and characterize, at the molecular level, novel adhesion and colonization factors in STEC strains, with an emphasis on their contribution to virulence traits, their host-pathogen interactions, the regulatory mechanisms controlling their expression, and their role as targets eliciting immune responses in the host.
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Affiliation(s)
- Mauricio J. Farfan
- Centro de Estudios Moleculares, Departamento de Pediatría, Hospital Dr. Luis Calvo Mackenna, Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Alfredo G. Torres
- Department of Microbiology and Immunology, Department of Pathology, Sealy Center for Vaccine Development, and Center for Tropical Diseases, University of Texas Medical Branch, Galveston, Texas, USA
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Fimbrial adhesins produced by atypical enteropathogenic Escherichia coli strains. Appl Environ Microbiol 2011; 77:8391-9. [PMID: 21926222 DOI: 10.1128/aem.05376-11] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Atypical enteropathogenic Escherichia coli (aEPEC) has emerged as a significant cause of pediatric diarrhea worldwide; however, information regarding its adherence mechanisms to the human gut mucosa is lacking. In this study, we investigated the prevalence of several (fimA, ecpA, csgA, elfA, and hcpA) fimbrial genes in 71 aEPEC strains isolated from children with diarrhea (54 strains) and healthy individuals (17 strains) in Brazil and Australia by PCR. These genes are associated with adhesion and/or biofilm formation of pathogenic and commensal E. coli. Here, the most prevalent fimbrial genes found, in descending order, were hcpA (98.6%), ecpA (86%), fimA (76%), elfA (72%), and csgA (19.7%). Phenotypic expression of pili in aEPEC strains was assessed by several approaches. We were not able to detect the hemorrhagic coli pilus (HCP) or the E. coli laminin-binding fimbriae (ELF) in these strains by using immunofluorescence. Type 1 pili and curli were detected in 59% (by yeast agglutination) and 2.8% (by Congo red binding and immunofluorescence) of the strains, respectively. The E. coli common pilus (ECP) was evidenced in 36.6% of the strains on bacteria adhering to HeLa cells by immunofluorescence, suggesting that ECP could play an important role in cell adherence for some aEPEC strains. This study highlights the complex nature of the adherence mechanisms of aEPEC strains involving the coordinated function of fimbrial (e.g., ECP) and nonfimbrial (e.g., intimin) adhesins and indicates that these strains bear several pilus operons that could potentially be expressed in different niches favoring colonization and survival in and outside the host.
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Parti RP, Biswas D, Wang M, Liao M, Dillon JAR. A minD mutant of enterohemorrhagic E. coli O157:H7 has reduced adherence to human epithelial cells. Microb Pathog 2011; 51:378-83. [PMID: 21798335 DOI: 10.1016/j.micpath.2011.07.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2010] [Revised: 06/29/2011] [Accepted: 07/06/2011] [Indexed: 11/29/2022]
Abstract
Adherence to epithelial cells is a prerequisite for intestinal colonization by the bacterial pathogen, enterohemorrhagic Escherichia coli (EHEC). The deletion of minD, a cell division gene, in EHEC caused reduced adherence to human epithelioid cervical carcinoma (HeLa) and human colonic adenocarcinoma (Caco-2) cells as compared to wild-type. The minD mutant formed minicells and filaments owing to aberrant cytokinesis. Moreover, its ability to form microcolonies as typically seen in the co-cultures of wild-type with Caco-2 cells, was abolished. In conclusion, the present study highlights the importance of minD in regards to EHEC adherence to human epithelial cells.
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Affiliation(s)
- Rajinder P Parti
- Vaccine and Infectious Disease Organization, University of Saskatchewan, Saskatoon, SK, Canada S7N 5E3
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Long polar fimbriae of enterohemorrhagic Escherichia coli O157:H7 bind to extracellular matrix proteins. Infect Immun 2011; 79:3744-50. [PMID: 21708988 DOI: 10.1128/iai.05317-11] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Adherence to intestinal cells is a key process in infection caused by enterohemorrhagic Escherichia coli (EHEC). Several adhesion factors that mediate the binding of EHEC to intestinal cells have been described, but the receptors involved in their recognition are not fully characterized. Extracellular matrix (ECM) proteins might act as receptors involved in the recognition of enteric pathogens, including EHEC. In this study, we sought to characterize the binding of EHEC O157:H7 to ECM proteins commonly present in the intestine. We found that EHEC prototype strains as well as other clinical isolates adhered more abundantly to surfaces coated with fibronectin, laminin, and collagen IV. Further characterization of this phenotype, by using antiserum raised against the LpfA1 putative major fimbrial subunit and by addition of mannose, showed that a reduced binding of EHEC to ECM proteins was observed in a long polar fimbria (lpf) mutant. We also found that the two regulators, H-NS and Ler, had an effect in EHEC Lpf-mediated binding to ECM, supporting the roles of these tightly regulated fimbriae as adherence factors. Purified Lpf major subunit bound to all of the ECM proteins tested. Finally, increased bacterial adherence was observed when T84 cells, preincubated with ECM proteins, were infected with EHEC. Taken together, these findings suggest that the interaction of Lpf and ECM proteins contributes to the EHEC colonization of the gastrointestinal tract.
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Saldaña Z, Sánchez E, Xicohtencatl-Cortes J, Puente JL, Girón JA. Surface structures involved in plant stomata and leaf colonization by shiga-toxigenic Escherichia coli o157:h7. Front Microbiol 2011; 2:119. [PMID: 21887151 PMCID: PMC3157101 DOI: 10.3389/fmicb.2011.00119] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2010] [Accepted: 05/12/2011] [Indexed: 01/03/2023] Open
Abstract
Shiga-toxigenic Escherichia coli (STEC) O157:H7 uses a myriad of surface adhesive appendages including pili, flagella, and the type 3 secretion system (T3SS) to adhere to and inflict damage to the human gut mucosa. Consumption of contaminated ground beef, milk, juices, water, or leafy greens has been associated with outbreaks of diarrheal disease in humans due to STEC. The aim of this study was to investigate which of the known STEC O157:H7 adherence factors mediate colonization of baby spinach leaves and where the bacteria reside within tainted leaves. We found that STEC O157:H7 colonizes baby spinach leaves through the coordinated production of curli, the E. coli common pilus, hemorrhagic coli type 4 pilus, flagella, and T3SS. Electron microscopy analysis of tainted leaves revealed STEC bacteria in the internal cavity of the stomata, in intercellular spaces, and within vascular tissue (xylem and phloem), where the bacteria were protected from the bactericidal effect of gentamicin, sodium hypochlorite or ozonated water treatments. We confirmed that the T3S escN mutant showed a reduced number of bacteria within the stomata suggesting that T3S is required for the successful colonization of leaves. In agreement, non-pathogenic E. coli K-12 strain DH5α transformed with a plasmid carrying the locus of enterocyte effacement (LEE) pathogenicity island, harboring the T3SS and effector genes, internalized into stomata more efficiently than without the LEE. This study highlights a role for pili, flagella, and T3SS in the interaction of STEC with spinach leaves. Colonization of plant stomata and internal tissues may constitute a strategy by which STEC survives in a nutrient-rich microenvironment protected from external foes and may be a potential source for human infection.
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Affiliation(s)
- Zeus Saldaña
- Department of Molecular Genetics and Microbiology, Emerging Pathogens Institute, University of Florida Gainesville, FL, USA
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Archer CT, Kim JF, Jeong H, Park JH, Vickers CE, Lee SY, Nielsen LK. The genome sequence of E. coli W (ATCC 9637): comparative genome analysis and an improved genome-scale reconstruction of E. coli. BMC Genomics 2011; 12:9. [PMID: 21208457 PMCID: PMC3032704 DOI: 10.1186/1471-2164-12-9] [Citation(s) in RCA: 126] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2010] [Accepted: 01/06/2011] [Indexed: 01/21/2023] Open
Abstract
BACKGROUND Escherichia coli is a model prokaryote, an important pathogen, and a key organism for industrial biotechnology. E. coli W (ATCC 9637), one of four strains designated as safe for laboratory purposes, has not been sequenced. E. coli W is a fast-growing strain and is the only safe strain that can utilize sucrose as a carbon source. Lifecycle analysis has demonstrated that sucrose from sugarcane is a preferred carbon source for industrial bioprocesses. RESULTS We have sequenced and annotated the genome of E. coli W. The chromosome is 4,900,968 bp and encodes 4,764 ORFs. Two plasmids, pRK1 (102,536 bp) and pRK2 (5,360 bp), are also present. W has unique features relative to other sequenced laboratory strains (K-12, B and Crooks): it has a larger genome and belongs to phylogroup B1 rather than A. W also grows on a much broader range of carbon sources than does K-12. A genome-scale reconstruction was developed and validated in order to interrogate metabolic properties. CONCLUSIONS The genome of W is more similar to commensal and pathogenic B1 strains than phylogroup A strains, and therefore has greater utility for comparative analyses with these strains. W should therefore be the strain of choice, or 'type strain' for group B1 comparative analyses. The genome annotation and tools created here are expected to allow further utilization and development of E. coli W as an industrial organism for sucrose-based bioprocesses. Refinements in our E. coli metabolic reconstruction allow it to more accurately define E. coli metabolism relative to previous models.
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Affiliation(s)
- Colin T Archer
- Australian Institute for Bioengineering and Nanotechnology, Cnr Cooper and College Rds, The University of Queensland, St Lucia, Queensland 4072 Australia
| | - Jihyun F Kim
- Industrial Biotechnology and Bioenergy Research Center, Korea Research Institute of Bioscience and Biotechnology, 111 Gwahangno, Yuseong-gu, Daejeon, Korea
| | - Haeyoung Jeong
- Industrial Biotechnology and Bioenergy Research Center, Korea Research Institute of Bioscience and Biotechnology, 111 Gwahangno, Yuseong-gu, Daejeon, Korea
| | - Jin Hwan Park
- Department of Chemical and Biomolecular Engineering (BK21 program) and Center for Systems and Synthetic Biotechnology, Institute for the BioCentury, KAIST, 335 Gwahangno, Yuseong-gu, Daejeon 305-701, Republic of Korea
| | - Claudia E Vickers
- Australian Institute for Bioengineering and Nanotechnology, Cnr Cooper and College Rds, The University of Queensland, St Lucia, Queensland 4072 Australia
| | - Sang Yup Lee
- Department of Chemical and Biomolecular Engineering (BK21 program) and Center for Systems and Synthetic Biotechnology, Institute for the BioCentury, KAIST, 335 Gwahangno, Yuseong-gu, Daejeon 305-701, Republic of Korea
| | - Lars K Nielsen
- Australian Institute for Bioengineering and Nanotechnology, Cnr Cooper and College Rds, The University of Queensland, St Lucia, Queensland 4072 Australia
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Korea CG, Badouraly R, Prevost MC, Ghigo JM, Beloin C. Escherichia coli K-12 possesses multiple cryptic but functional chaperone-usher fimbriae with distinct surface specificities. Environ Microbiol 2010; 12:1957-77. [PMID: 20345943 DOI: 10.1111/j.1462-2920.2010.02202.x] [Citation(s) in RCA: 131] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Commensal and pathogenic Escherichia coli adherence to host and environmental surfaces is mediated by a variety of adhesins. Although extensively studied as a model bacterium, 34% of the genes in the E. coli K-12 genome have no known function. We hypothesized that some of them may correspond to functional adhesins. We characterized E. coli K-12 ycb, ybg, yfc, yad, yra, sfm and yeh operons, which display sequence and organizational homologies to type 1 fimbriae exported by the chaperone/usher pathway. We showed that, although these operons are poorly expressed under laboratory conditions, six of them are nevertheless functional when expressed, and promote adhesion to abiotic and/or epithelial cell surfaces. While the studied fimbriae display different binding specificities, we obtained evidence of synergy/interference with other adhesins such as Ag43 or type 1 fimbriae. We showed that their expression is under the negative control of H-NS and, except for yad, subjected to cAMP receptor protein-mediated activation and carbon catabolite repression. These results therefore demonstrate that ycb, yfc, yad, yra, sfm and yeh operons encode cryptic but functional fimbriae adhesins whose expression following environmental modifications could contribute to E. coli's ability to adhere to and colonize a wide diversity of surfaces in its various ecological niches.
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Affiliation(s)
- Charalampia-Georgia Korea
- Institut Pasteur, Unité de Génétique des Biofilms, CNRS URA 2172, 25-28 rue du Dr Roux, 750724 Paris Cedex 15, France
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