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Del Carpio AMG, Freire CA, Andrade FB, Piazza RMF, Silva RM, Carvalho E, Elias WP. Genomic Dissection of an Enteroaggregative Escherichia coli Strain Isolated from Bacteremia Reveals Insights into Its Hybrid Pathogenic Potential. Int J Mol Sci 2024; 25:9238. [PMID: 39273188 PMCID: PMC11394720 DOI: 10.3390/ijms25179238] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2024] [Revised: 07/10/2024] [Accepted: 07/16/2024] [Indexed: 09/15/2024] Open
Abstract
Escherichia coli is a frequent pathogen isolated from bloodstream infections. This study aimed to characterize the genetic features of EC092, an E. coli strain isolated from bacteremia that harbors enteroaggregative E. coli (EAEC) genetic markers, indicating its hybrid pathogenic potential. Whole-genome sequencing showed that EC092 belongs to phylogroup B1, ST278, and serotype O165:H4. Genes encoding virulence factors such as fimbriae, toxins, iron-uptake systems, autotransporter proteins (Pet, Pic, Sat, and SepA), and secretion systems were detected, as well as EAEC virulence genes (aggR, aatA, aaiC, and aap). EC092 was found to be closely related to the other EAEC prototype strains and highly similar in terms of virulence to three EAEC strains isolated from diarrhea. The genomic neighborhood of pet, pic, sat, sepA, and the EAEC virulence genes of EC092 and its three genetically related fecal EAEC strains showed an identical genomic organization and nucleotide sequences. Also, EC092 produced and secreted Pet, Pic, Sat, and SepA in the culture supernatant and resisted the bactericidal activity of normal human serum. Our results demonstrate that the strain EC092, isolated from bacteremia, is a hybrid pathogenic extraintestinal E. coli (ExPEC)/EAEC with virulence features that could mediate both extraintestinal and intestinal infections.
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Affiliation(s)
| | - Claudia A Freire
- Laboratório de Bacteriologia, Instituto Butantan, São Paulo 05503-900, Brazil
| | - Fernanda B Andrade
- Laboratório de Bacteriologia, Instituto Butantan, São Paulo 05503-900, Brazil
| | - Roxane M F Piazza
- Laboratório de Bacteriologia, Instituto Butantan, São Paulo 05503-900, Brazil
| | - Rosa M Silva
- Departamento de Microbiologia, Imunologia e Parasitologia, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo 04023-062, Brazil
| | - Eneas Carvalho
- Laboratório de Bacteriologia, Instituto Butantan, São Paulo 05503-900, Brazil
| | - Waldir P Elias
- Laboratório de Bacteriologia, Instituto Butantan, São Paulo 05503-900, Brazil
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Irudal S, Scoffone VC, Trespidi G, Barbieri G, D'Amato M, Viglio S, Pizza M, Scarselli M, Riccardi G, Buroni S. Identification by Reverse Vaccinology of Three Virulence Factors in Burkholderia cenocepacia That May Represent Ideal Vaccine Antigens. Vaccines (Basel) 2023; 11:1039. [PMID: 37376428 DOI: 10.3390/vaccines11061039] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Revised: 05/24/2023] [Accepted: 05/26/2023] [Indexed: 06/29/2023] Open
Abstract
The Burkholderia cepacia complex comprises environmental and clinical Gram-negative bacteria that infect particularly debilitated people, such as those with cystic fibrosis. Their high level of antibiotic resistance makes empirical treatments often ineffective, increasing the risk of worst outcomes and the diffusion of multi-drug resistance. However, the discovery of new antibiotics is not trivial, so an alternative can be the use of vaccination. Here, the reverse vaccinology approach has been used to identify antigen candidates, obtaining a short-list of 24 proteins. The localization and different aspects of virulence were investigated for three of them-BCAL1524, BCAM0949, and BCAS0335. The three antigens were localized in the outer membrane vesicles confirming that they are surface exposed. We showed that BCAL1524, a collagen-like protein, promotes bacteria auto-aggregation and plays an important role in virulence, in the Galleria mellonella model. BCAM0949, an extracellular lipase, mediates piperacillin resistance, biofilm formation in Luria Bertani and artificial sputum medium, rhamnolipid production, and swimming motility; its predicted lipolytic activity was also experimentally confirmed. BCAS0335, a trimeric adhesin, promotes minocycline resistance, biofilm organization in LB, and virulence in G. mellonella. Their important role in virulence necessitates further investigations to shed light on the usefulness of these proteins as antigen candidates.
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Affiliation(s)
- Samuele Irudal
- Department of Biology and Biotechnology "Lazzaro Spallanzani", University of Pavia, 27100 Pavia, Italy
| | - Viola Camilla Scoffone
- Department of Biology and Biotechnology "Lazzaro Spallanzani", University of Pavia, 27100 Pavia, Italy
| | - Gabriele Trespidi
- Department of Biology and Biotechnology "Lazzaro Spallanzani", University of Pavia, 27100 Pavia, Italy
| | - Giulia Barbieri
- Department of Biology and Biotechnology "Lazzaro Spallanzani", University of Pavia, 27100 Pavia, Italy
| | - Maura D'Amato
- Department of Molecular Medicine, University of Pavia, 27100 Pavia, Italy
| | - Simona Viglio
- Department of Molecular Medicine, University of Pavia, 27100 Pavia, Italy
| | | | | | - Giovanna Riccardi
- Department of Biology and Biotechnology "Lazzaro Spallanzani", University of Pavia, 27100 Pavia, Italy
| | - Silvia Buroni
- Department of Biology and Biotechnology "Lazzaro Spallanzani", University of Pavia, 27100 Pavia, Italy
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Kwasi DA, Babalola CP, Olubiyi OO, Hoffmann J, Uzochukwu IC, Okeke IN. Antibiofilm agents with therapeutic potential against enteroaggregative Escherichia coli. PLoS Negl Trop Dis 2022; 16:e0010809. [PMID: 36201560 PMCID: PMC9578610 DOI: 10.1371/journal.pntd.0010809] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Revised: 10/18/2022] [Accepted: 09/12/2022] [Indexed: 12/01/2022] Open
Abstract
BACKGROUND Enteroaggregative Escherichia coli (EAEC) is a predominant but neglected enteric pathogen implicated in infantile diarrhoea and nutrient malabsorption. There are no non-antibiotic approaches to dealing with persistent infection by these exceptional colonizers, which form copious biofilms. We screened the Medicines for Malaria Venture Pathogen Box for chemical entities that inhibit EAEC biofilm formation. METHODOLOGY We used EAEC strains, 042 and MND005E in a medium-throughput crystal violet-based antibiofilm screen. Hits were confirmed in concentration-dependence, growth kinetic and time course assays and activity spectra were determined against a panel of 25 other EAEC strains. Antibiofilm activity against isogenic EAEC mutants, molecular docking simulations and comparative genomic analysis were used to identify the mechanism of action of one hit. PRINCIPAL FINDINGS In all, five compounds (1.25%) reproducibly inhibited biofilm accumulation by at least one strain by 30-85% while inhibiting growth by under 10%. Hits exhibited potent antibiofilm activity at concentrations at least 10-fold lower than those reported for nitazoxanide, the only known EAEC biofilm inhibitor. Reflective of known EAEC heterogeneity, only one hit was active against both screen isolates, but three hits showed broad antibiofilm activity against a larger panel of strains. Mechanism of action studies point to the EAEC anti-aggregation protein (Aap), dispersin, as the target of compound MMV687800. CONCLUSIONS This study identified five compounds, not previously described as anti-adhesins or Gram-negative antibacterials, with significant EAEC antibiofilm activity. Molecule, MMV687800 targets the EAEC Aap. In vitro small-molecule inhibition of EAEC colonization opens a way to new therapeutic approaches against EAEC infection.
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Affiliation(s)
- David A. Kwasi
- Department of Pharmaceutical Microbiology, Faculty of Pharmacy, University of Ibadan, Oyo State, Nigeria
- Department of Pharmaceutical Chemistry, Faculty of Pharmacy, University of Ibadan, Ibadan, Oyo State, Nigeria
| | - Chinedum P. Babalola
- Department of Pharmaceutical Chemistry, Faculty of Pharmacy, University of Ibadan, Ibadan, Oyo State, Nigeria
- Center for Drug Discovery, Development and Production, Faculty of Pharmacy, University of Ibadan, Oyo State, Nigeria
| | - Olujide O. Olubiyi
- Department of Pharmaceutical and Medicinal Chemistry, College of Pharmacy, Afe Babalola University, Ado-Ekiti, Nigeria
| | - Jennifer Hoffmann
- Department of Biology, Haverford College, Haverford, Pennsylvania, United States of America
| | - Ikemefuna C. Uzochukwu
- Department of Pharmaceutical and Medicinal Chemistry, Faculty of Pharmaceutical Sciences, Nnamdi Azikiwe University Awka, Anambra State, Nigeria
| | - Iruka N. Okeke
- Department of Pharmaceutical Microbiology, Faculty of Pharmacy, University of Ibadan, Oyo State, Nigeria
- Department of Biology, Haverford College, Haverford, Pennsylvania, United States of America
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Yamamura F, Sugiura T, Munby M, Shiokura Y, Murata R, Nakamura T, Fujiki J, Iwano H. Relationship between Escherichia coli virulence factors, notably kpsMTII, and symptoms of clinical metritis and endometritis in dairy cows. J Vet Med Sci 2022; 84:420-428. [PMID: 35082195 PMCID: PMC8983293 DOI: 10.1292/jvms.21-0586] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Although Escherichia coli is a commensal bacterium of the bovine vaginal microbiota, it is an important pathogenic bacterium that causes diseases of the reproductive tract and sub-fertility. Recent studies have focused on virulence factors (VFs) of intrauterine E. coli; however, actual endometrial VFs have not been clearly identified. The purpose of this study was to identify the VFs of E. coli associated with clinical metritis and endometritis. Thirty-two strains of E. coli and four mixed Trueperella pyogenes (TP) strains were detected in the uterus of 19 Holstein dairy cows with obvious clinical signs (between 8 and 66 days postpartum). The presence of six E. coli VFs (fimH, fyuA, kpsMTII, hra1, csgA, and astA) was examined by PCR, and clinical signs and reproductive performance (mixed TP, the percentage of polymorphonuclear neutrophils [PMN%], days to uterine involution, etc.) were evaluated. Four VFs (fimH, hra1, csgA, and astA) were detected in all E. coli strains, whereas fyuA and kpsMTII were detected in 94% and 50% of strains, respectively. Cows with E. coli strains harboring kpsMTII exhibited significantly severe clinical scores (vaginal discharge score, PMN%, uterine involution), suggesting that kpsMTII is a key VF for progression of clinical metritis and endometritis. In the present study, we clearly identified six VFs associated with clinical metritis and endometritis. In addition, E. coli strains with kpsMTII probably play a crucial role in the progression of clinical metritis and endometritis.
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Affiliation(s)
- Fuminosuke Yamamura
- Laboratory of Veterinary Biochemistry, School of Veterinary Medicine, Rakuno Gakuen University
| | - Tomochika Sugiura
- Laboratory of Theriogenology, School of Veterinary Medicine, Rakuno Gakuen University
| | - Montgomery Munby
- Laboratory of Veterinary Biochemistry, School of Veterinary Medicine, Rakuno Gakuen University
| | - Yusei Shiokura
- Laboratory of Veterinary Biochemistry, School of Veterinary Medicine, Rakuno Gakuen University
| | - Ryo Murata
- Laboratory of Food Microbiology and Food Safety, School of Veterinary Medicine, Rakuno Gakuen University
| | - Tomohiro Nakamura
- Laboratory of Veterinary Biochemistry, School of Veterinary Medicine, Rakuno Gakuen University
| | - Jumpei Fujiki
- Laboratory of Veterinary Biochemistry, School of Veterinary Medicine, Rakuno Gakuen University
| | - Hidetomo Iwano
- Laboratory of Veterinary Biochemistry, School of Veterinary Medicine, Rakuno Gakuen University
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Soria-Bustos J, Saitz W, Medrano A, Lara-Ochoa C, Bennis Z, Monteiro-Neto V, Dos Santos CI, Rodrigues J, Hernandes RT, Yáñez JA, Torres J, Navarro-García F, Martínez-Laguna Y, Fontes Piazza RM, Munhoz DD, Cedillo ML, Ares MA, De la Cruz MA, Nataro JP, Girón JA. Role of the YehD fimbriae in the virulence-associated properties of enteroaggregative Escherichia coli. Environ Microbiol 2021; 24:1035-1051. [PMID: 34431194 DOI: 10.1111/1462-2920.15737] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Revised: 08/16/2021] [Accepted: 08/22/2021] [Indexed: 11/30/2022]
Abstract
The interaction of enteroaggregative Escherichia coli (EAEC) strains with the colonic gut mucosa is characterized by the ability of the bacteria to form robust biofilms, to bind mucin, and induce a local inflammatory response. These events are mediated by a repertoire of five different aggregative adherence fimbriae variants (AAF/I-V) typically encoded on virulence plasmids. In this study, we report the production in EAEC strains of a new YehD fimbriae (YDF), which is encoded by the chromosomal gene cluster yehABCD, also present in most E. coli strains. Immuno-labelling of EAEC strain 042 with anti-AAF/II and anti-YDF antibodies demonstrated the presence of both AAF/II and YDF on the bacterial surface. We investigated the role of YDF in cell adherence, biofilm formation, colonization of spinach leaves, and induction of pro-inflammatory cytokines release. To this aim, we constructed yehD deletion mutants in different EAEC backgrounds (strains 17-2, 042, 55989, C1010, 278-1, J7) each harbouring one of the five AAFs. The effect of the YDF mutation was strain dependent and AAF independent as the lack of YDF had a different impact on the phenotypes manifested by the different EAECs tested. Expression of the yehABCD operon in a E. coli K12 ORN172 showed that YDF is important for biofilm formation but not for adherence to HeLa cells. Lastly, screening of pro-inflammatory cytokines in supernatants of Caco-2 cells infected with EAEC strains 042 and J7 and their isogenic ΔyehD mutants showed that these mutants were significantly defective in release of IL-8 and TNF-α. This study contributes to the understanding of the complex and diverse mechanisms of adherence of EAEC strains and identifies a new potential target for preventive measures of gastrointestinal illness caused by EAEC and other E. coli pathogroups.
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Affiliation(s)
- Jorge Soria-Bustos
- Department of Pediatrics, University of Virginia School of Medicine, Charlottesville, VA, USA.,Unidad de Investigación Médica en Enfermedades Infecciosas y Parasitarias, Centro Médico Nacional Siglo XXI, Instituto Mexicano de Seguro Social, Ciudad de México, Mexico
| | - Waleska Saitz
- Department of Pediatrics, University of Virginia School of Medicine, Charlottesville, VA, USA
| | - Abraham Medrano
- Department of Pediatrics, University of Virginia School of Medicine, Charlottesville, VA, USA
| | - Cristina Lara-Ochoa
- Centro de Detección Biomolecular, Benemérita Universidad Autónoma de Puebla, Puebla, Mexico
| | - Zineb Bennis
- University of Florida, Emerging Pathogens Institute, Gainesville, FL, USA
| | | | | | - Josias Rodrigues
- Departamento de Microbiologia e Imunologia, Instituto de Biociencias da UNESP, Botucatu, SP, Brazil
| | - Rodrigo T Hernandes
- Departamento de Microbiologia e Imunologia, Instituto de Biociencias da UNESP, Botucatu, SP, Brazil
| | - Jorge A Yáñez
- Facultad de Estomatología, Benemérita Universidad Autónoma de Puebla, Puebla, Mexico
| | - Javier Torres
- Unidad de Investigación Médica en Enfermedades Infecciosas y Parasitarias, Centro Médico Nacional Siglo XXI, Instituto Mexicano de Seguro Social, Ciudad de México, Mexico
| | - Fernando Navarro-García
- Departamento de Biología Celular, Centro de Investigaciones Avanzadas, Instituto Politécnico Nacional, Ciudad de México, Mexico
| | - Ygnacio Martínez-Laguna
- Centro de Investigaciones en Ciencias Microbiológicas, Benemérita Universidad Autónoma de Puebla, Puebla, Mexico
| | | | | | - María L Cedillo
- Centro de Detección Biomolecular, Benemérita Universidad Autónoma de Puebla, Puebla, Mexico
| | - Miguel A Ares
- Unidad de Investigación Médica en Enfermedades Infecciosas y Parasitarias, Centro Médico Nacional Siglo XXI, Instituto Mexicano de Seguro Social, Ciudad de México, Mexico
| | - Miguel A De la Cruz
- Unidad de Investigación Médica en Enfermedades Infecciosas y Parasitarias, Centro Médico Nacional Siglo XXI, Instituto Mexicano de Seguro Social, Ciudad de México, Mexico
| | - James P Nataro
- Department of Pediatrics, University of Virginia School of Medicine, Charlottesville, VA, USA
| | - Jorge A Girón
- Department of Pediatrics, University of Virginia School of Medicine, Charlottesville, VA, USA.,Centro de Detección Biomolecular, Benemérita Universidad Autónoma de Puebla, Puebla, Mexico
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Nwoko ESQA, Okeke IN. Bacteria autoaggregation: how and why bacteria stick together. Biochem Soc Trans 2021; 49:1147-1157. [PMID: 34110370 PMCID: PMC8286834 DOI: 10.1042/bst20200718] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Revised: 05/02/2021] [Accepted: 05/12/2021] [Indexed: 12/16/2022]
Abstract
Autoaggregation, adherence between identical bacterial cells, is important for colonization, kin and kind recognition, and survival of bacteria. It is directly mediated by specific interactions between proteins or organelles on the surfaces of interacting cells or indirectly by the presence of secreted macromolecules such as eDNA and exopolysaccharides. Some autoaggregation effectors are self-associating and present interesting paradigms for protein interaction. Autoaggregation can be beneficial or deleterious at specific times and niches. It is, therefore, typically regulated through transcriptional or post-transcriptional mechanisms or epigenetically by phase variation. Autoaggregation can contribute to bacterial adherence, biofilm formation or other higher-level functions. However, autoaggregation is only required for these phenotypes in some bacteria. Thus, autoaggregation should be detected, studied and measured independently using both qualitative and quantitative in vitro and ex vivo methods. If better understood, autoaggregation holds the potential for the discovery of new therapeutic targets that could be cost-effectively exploited.
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Affiliation(s)
- El-shama Q. A. Nwoko
- Department of Pharmaceutical Microbiology, Faculty of Pharmacy, University of Ibadan, Ibadan, Oyo State, Nigeria
| | - Iruka N. Okeke
- Department of Pharmaceutical Microbiology, Faculty of Pharmacy, University of Ibadan, Ibadan, Oyo State, Nigeria
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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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Monárrez R, Okeke IN. A plasmid-encoded papB paralogue modulates autoaggregation of Escherichia coli transconjugants. BMC Res Notes 2020; 13:565. [PMID: 33317611 PMCID: PMC7734786 DOI: 10.1186/s13104-020-05405-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Accepted: 11/28/2020] [Indexed: 11/16/2022] Open
Abstract
Objective Plasmids are key to antimicrobial resistance transmission among enteric bacteria. It is becoming increasingly clear that resistance genes alone do not account for the selective advantage of plasmids and bacterial strains that harbor them. Deletion of a 32 Kb fitness-conferring region of pMB2, a conjugative resistance plasmid, produced a hyper-autoaggregation phenotype in laboratory Escherichia coli. This study sought to determine the genetic basis for hyper-autoaggregation conferred by the pMB2-derived mini-plasmid. Results The 32 Kb fragment deleted from pMB2 included previously characterized nutrient acquisition genes as well as putative transposase and integrase genes, a 272 bp papB/ pefB-like gene, and several open-reading frames of unknown function. We cloned the papB/ pefB paralogue and found it sufficient to temper the hyper-autoaggregation phenotype. Hyper-autoaggregation conferred by the mini-plasmid did not occur in a fim-negative background. This study has identified and characterized a gene capable of down-regulating host adhesins and has shown that trans-acting papB/pefB paralogues can occur outside the context of an adhesin cluster. This plasmid-mediated modification of a bacterial host’s colonization program may optimize horizontal transfer of the mobile element bearing the genes.
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Affiliation(s)
- Rubén Monárrez
- Department of Biology, Haverford College, Haverford, Pennsylvania, USA
| | - Iruka N Okeke
- Department of Biology, Haverford College, Haverford, Pennsylvania, USA. .,Department of Pharmaceutical Microbiology, Faculty of Pharmacy, University of Ibadan, Ibadan, Oyo State, Nigeria.
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In Silico Genotyping of Escherichia coli Isolates for Extraintestinal Virulence Genes by Use of Whole-Genome Sequencing Data. J Clin Microbiol 2020; 58:JCM.01269-20. [PMID: 32669379 PMCID: PMC7512150 DOI: 10.1128/jcm.01269-20] [Citation(s) in RCA: 196] [Impact Index Per Article: 49.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Accepted: 07/08/2020] [Indexed: 12/14/2022] Open
Abstract
Extraintestinal pathogenic Escherichia coli (ExPEC) is the leading cause in humans of urinary tract infection and bacteremia. The previously published web tool VirulenceFinder (http://cge.cbs.dtu.dk/services/VirulenceFinder/) uses whole-genome sequencing (WGS) data for in silico characterization of E. coli isolates and enables researchers and clinical health personnel to quickly extract and interpret virulence-relevant information from WGS data. In this study, 38 ExPEC-associated virulence genes were added to the existing E. coli VirulenceFinder database. In total, 14,441 alleles were downloaded. A total of 1,890 distinct alleles were added to the database after removal of redundant sequences and analysis of the remaining alleles for open reading frames (ORFs). The database now contains 139 genes-of which 44 are related to ExPEC-and 2,826 corresponding alleles. Construction of the database included validation against 27 primer pairs from previous studies, a search for serotype-specific P fimbriae papA alleles, and a BLASTn confirmation of seven genes (etsC, iucC, kpsE, neuC, sitA, tcpC, and terC) not covered by the primers. The augmented database was evaluated using (i) a panel of nine control strains and (ii) 288 human-source E. coli strains classified by PCR as ExPEC and non-ExPEC. We observed very high concordance (average, 93.4%) between PCR and WGS findings, but WGS identified more alleles. In conclusion, the addition of 38 ExPEC-associated genes and the associated alleles to the E. coli VirulenceFinder database allows for a more complete characterization of E. coli isolates based on WGS data, which has become increasingly important considering the plasticity of the E. coli genome.
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10
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Silva SS, Monfardini MV, Scaletsky ICA. Large plasmids encoding antibiotic resistance and localized-like adherence in atypical enteropathogenic Escherichia coli strains. BMC Microbiol 2020; 20:138. [PMID: 32471348 PMCID: PMC7257209 DOI: 10.1186/s12866-020-01809-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Accepted: 04/30/2020] [Indexed: 12/05/2022] Open
Abstract
Background In previous studies, we have shown that atypical enteropathogenic Escherichia coli (aEPEC) strains are important diarrheal pathogens among Brazilian children. In the characterization of a collection of 126 aEPEC strains, we identified 29 strains expressing the localized-like adherence (LAL) pattern on HEp-2 cells and harboring large plasmids in the range of 60 to 98 MDa. In this study, we examined 18 of these strains for their ability to transfer the LAL phenotype to a E. coli K-12 C600 strain. Results In conjugation experiments, using eight strains which were resistant to one or more antimicrobials and positive for F-pili genes (traA), we were able to cotransfer antimicrobial resistance markers along with adhesion genes. By transforming E. coli DH5α with plasmid DNA from strains A46 (pIS46), A66 (pIS66) and A102 (pIS102), we were able to demonstrate that genes encoding ampicillin, tetracycline and LAL were encoded on a 98-MDa conjugative plasmid. To identify a gene responsible for LAL, we constructed a transposon mutant library of A102 strain. Among 18 mutants that did not adhere to HeLa cells, four carried insertions within fimbrial genes (fimA and traJ) and agglutinin genes (tia and hek). Using these Tn5 mutants as donors, we were able to obtain kanamycin-resistant E. coli MA3456 transconjugants. Sequence analysis of the plasmid genes revealed a region exhibit to 80 and 73% amino acid similarities to the agglutinins Tia and Hek, respectively. Conclusion In this study, we have identified three large conjugative plasmids, pIS46, pIS66 and pIS102, coding for antimicrobial resistance and localized-like adherence (LAL) to HeLa cells. In addition, we identified a tia/hek homolog encoded on the pIS102 plasmid, which seems to be involved in adhesion of A102 strain.
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Affiliation(s)
- Scarlat S Silva
- Departamento de Microbiologia, Imunologia e Parasitologia, Universidade Federal de São Paulo, Escola Paulista de Medicina, Rua Botucatu, 862, 3 andar, São Paulo, 04023-062, Brazil
| | - Mariane V Monfardini
- Departamento de Microbiologia, Imunologia e Parasitologia, Universidade Federal de São Paulo, Escola Paulista de Medicina, Rua Botucatu, 862, 3 andar, São Paulo, 04023-062, Brazil
| | - Isabel C A Scaletsky
- Departamento de Microbiologia, Imunologia e Parasitologia, Universidade Federal de São Paulo, Escola Paulista de Medicina, Rua Botucatu, 862, 3 andar, São Paulo, 04023-062, Brazil.
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11
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Petro CD, Duncan JK, Seldina YI, Allué-Guardia A, Eppinger M, Riddle MS, Tribble DR, Johnson RC, Dalgard CL, Sukumar G, Connor P, Boisen N, Melton-Celsa AR. Genetic and Virulence Profiles of Enteroaggregative Escherichia coli (EAEC) Isolated From Deployed Military Personnel (DMP) With Travelers' Diarrhea. Front Cell Infect Microbiol 2020; 10:200. [PMID: 32509590 PMCID: PMC7251025 DOI: 10.3389/fcimb.2020.00200] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Accepted: 04/16/2020] [Indexed: 02/01/2023] Open
Abstract
To discern if there was a particular genotype associated with clinical enteroaggregative Escherichia coli (EAEC) strains isolated from deployed military personnel (DMP) with travelers' diarrhea (TD), we characterized a collection of EAEC from DMP deployed to Afghanistan, Djibouti, Kenya, or Honduras. Although we did not identify a specific EAEC genotype associated with TD in DMP, we found that EAEC isolated at the first clinic visit were more likely to encode the dispersin gene aap than EAEC collected at follow-up visits. A majority of the EAEC isolates were typical EAEC that adhered to HEp-2 cells, formed biofilms, and harbored genes for aggregative adherence fimbriae (AAF), AggR, and serine protease autotransporters of Enterobacteriaceae (SPATEs). A separate subset of the EAEC had aggR and genes for SPATEs but encoded a gene highly homologous to that for CS22, a fimbriae more commonly found in enterotoxigenic E. coli. None of these CS22-encoding EAEC formed biofilms in vitro or adhered to HEp-2 cells. Whole genome sequence and single nucleotide polymorphism analyses demonstrated that most of the strains were genetically diverse, but that a few were closely related. Isolation of these related strains occurred within days to more than a year apart, a finding that suggests a persistent source and genomic stability. In an ampicillin-treated mouse model we found that an agg4A+ aar- isolate formed a biofilm in the intestine and caused reduced weight gain in mice, whereas a strain that did not form an in vivo biofilm caused no morbidity. Our diverse strain collection from DMP displays the heterogeneity of EAEC strains isolated from human patients, and our mouse model of infection indicated the genotype agg4A+ aar– and/or capacity to form biofilm in vivo may correlate to disease severity.
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Affiliation(s)
- Courtney D Petro
- Department of Microbiology and Immunolgy, Uniformed Services University of the Health Sciences, Bethesda, MD, United States
| | - Jeffrey K Duncan
- Department of Microbiology and Immunolgy, Uniformed Services University of the Health Sciences, Bethesda, MD, United States
| | - Yuliya I Seldina
- Walter Reed National Military Medical Center, Bethesda, MD, United States
| | - Anna Allué-Guardia
- Department of Biology, The University of Texas at San Antonio, San Antonio, TX, United States.,South Texas Center for Emerging Infectious Diseases, San Antonio, TX, United States
| | - Mark Eppinger
- Department of Biology, The University of Texas at San Antonio, San Antonio, TX, United States.,South Texas Center for Emerging Infectious Diseases, San Antonio, TX, United States
| | - Mark S Riddle
- Department of Preventative Medicine and Biostatistics, Uniformed Services University of the Health Sciences, Bethesda, MD, United States
| | - David R Tribble
- Department of Preventative Medicine and Biostatistics, Uniformed Services University of the Health Sciences, Bethesda, MD, United States
| | - Ryan C Johnson
- Department of Preventative Medicine and Biostatistics, Uniformed Services University of the Health Sciences, Bethesda, MD, United States
| | - Clifton L Dalgard
- Department of Anatomy, Physiology and Genetics, Uniformed Services University of the Health Sciences, Bethesda, MD, United States.,The American Genome Center, Uniformed Services University of the Health Sciences, Bethesda, MD, United States
| | - Gauthaman Sukumar
- The American Genome Center, Uniformed Services University of the Health Sciences, Bethesda, MD, United States.,Collaborative Health Initiative Research Program, Henry Jackson Foundation, Bethesda, MD, United States
| | - Patrick Connor
- Military Enteric Disease Group, Academic Department of Military Medicine, Birmingham, United Kingdom
| | - Nadia Boisen
- Department of Bacteria, Parasites and Fungi, Statens Serum Institut, Copenhagen, Denmark
| | - Angela R Melton-Celsa
- Department of Microbiology and Immunolgy, Uniformed Services University of the Health Sciences, Bethesda, MD, United States
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12
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Dias RCB, Tanabe RHS, Vieira MA, Cergole-Novella MC, Dos Santos LF, Gomes TAT, Elias WP, Hernandes RT. Analysis of the Virulence Profile and Phenotypic Features of Typical and Atypical Enteroaggregative Escherichia coli (EAEC) Isolated From Diarrheal Patients in Brazil. Front Cell Infect Microbiol 2020; 10:144. [PMID: 32391284 PMCID: PMC7188757 DOI: 10.3389/fcimb.2020.00144] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Accepted: 03/19/2020] [Indexed: 12/24/2022] Open
Abstract
Enteroaggregative Escherichia coli (EAEC) is an important agent of acute and persistent diarrhea in children and adults worldwide. Here we report a characterization of 220 EAEC isolates, 88.2% (194/220) of which were typical and 11.8% (26/220) were atypical, obtained from diarrheal patients during seven years (2010-2016) of epidemiological surveillance in Brazil. The majority of the isolates were assigned to phylogroups A (44.1%, 97/220) or B1 (21.4%, 47/220). The aggregative adherence (AA) pattern was detected in 92.7% (204/220) of the isolates, with six of them exhibiting AA concomitantly with a chain-like adherence pattern; and agg5A and agg4A were the most common adhesin-encoding genes, which were equally detected in 14.5% (32/220) of the isolates. Each of 12 virulence factor-encoding genes (agg4A, agg5A, pic, aap, aaiA, aaiC, aaiG, orf3, aar, air, capU, and shf) were statistically associated with typical EAEC (P < 0.05). The genes encoding the newly described aggregate-forming pili (AFP) searched (afpB, afpD, afpP, and afpA2), and/or its regulator (afpR), were exclusively detected in atypical EAEC (57.7%, 15/26), and showed a significant association with this subgroup of EAEC (P < 0.001). In conclusion, we presented an extensive characterization of the EAEC circulating in the Brazilian settings and identified the afp genes as putative markers for increasing the efficiency of atypical EAEC diagnosis.
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Affiliation(s)
- Regiane C B Dias
- Universidade Estadual Paulista (UNESP), Instituto de Biociências, São Paulo, Brazil
| | - Rodrigo H S Tanabe
- Universidade Estadual Paulista (UNESP), Instituto de Biociências, São Paulo, Brazil
| | - Melissa A Vieira
- Universidade Estadual Paulista (UNESP), Instituto de Biociências, São Paulo, Brazil
| | | | | | - Tânia A T Gomes
- Departamento de Microbiologia, Imunologia e Parasitologia, Universidade Federal de São Paulo- Escola Paulista de Medicina (UNIFESP-EPM), São Paulo, Brazil
| | - Waldir P Elias
- Laboratório de Bacteriologia, Instituto Butantan, São Paulo, Brazil
| | - Rodrigo T Hernandes
- Universidade Estadual Paulista (UNESP), Instituto de Biociências, São Paulo, Brazil
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13
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Antibiotic resistance and molecular characterization of enteroaggregative Escherichia coli isolated from patients with diarrhea in the Eastern Province of Saudi Arabia. Heliyon 2020; 6:e03721. [PMID: 32274438 PMCID: PMC7132075 DOI: 10.1016/j.heliyon.2020.e03721] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2019] [Revised: 01/22/2020] [Accepted: 03/30/2020] [Indexed: 11/22/2022] Open
Abstract
Aim To investigate presence of Enteroaggregative Escherichia coli (EAEC) in patients suffering with diarrhea by targeting the pCVD432 (pAA) gene using PCR. Methods There were 63 non-duplicate isolates of E. coli isolated from diarrheal cases in teaching hospital in Eastern Province of Saudi Arabia between May 2013 to July 2014. All E. coli strains were examined for antibiotic susceptibility testing and polymerase chain reaction (PCR) for detection of virulence gene markers for EAEC. Results Of the 63 E coli strains that were reported with diarrheal cases, 35 (55.6%) EAEC were tested positive for pCVD432 gene and aggR gene was present in 19 (54.3%) strains. All strains tested positive for pCVD432 and aggR genes were classified as typical EAEC (tEAEC). EAEC revealed resistance to tetracycline, ampicillin, nalidixic acid, trimethoprim sulfamethoxazole, ciprofloxacin, streptomycin, noroxin, and piperacillin. Conclusion EAEC was detected for the first time, among Saudi patients with diarrhea in this region of Saudi Arabia. The reported antibiotic resistance in this study is considered high among isolated EAEC strains to routinely prescribed antibiotics in our area.
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14
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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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15
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Aggregative Adherence and Intestinal Colonization by Enteroaggregative Escherichia coli Are Produced by Interactions among Multiple Surface Factors. mSphere 2018; 3:mSphere00078-18. [PMID: 29577084 PMCID: PMC5863034 DOI: 10.1128/msphere.00078-18] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2018] [Accepted: 02/10/2018] [Indexed: 11/20/2022] Open
Abstract
Enteroaggregative Escherichia coli (EAEC) bacteria are exceptional colonizers of the human intestine and can cause diarrhea. Compared to other E. coli pathogens, little is known about the genes and pathogenic mechanisms that differentiate EAEC from harmless commensal E. coli. EAEC bacteria attach via multiple proteins and structures, including long appendages produced by assembling molecules of AafA and a short surface protein called Hra1. EAEC also secretes an antiadherence protein (Aap; also known as dispersin) which remains loosely attached to the cell surface. This report shows that dispersin covers Hra1 such that the adhesive properties of EAEC seen in the laboratory are largely produced by AafA structures. When the bacteria colonize worms, dispersin is sloughed off, or otherwise removed, such that Hra1-mediated adherence occurs. All three factors are required for optimal colonization, as well as to produce the signature EAEC stacked-brick adherence pattern. Interplay among multiple colonization factors may be an essential feature of exceptional colonizers. Enteroaggregative Escherichia coli (EAEC) bacteria are exceptional colonizers that are associated with diarrhea. The genome of EAEC strain 042, a diarrheal pathogen validated in a human challenge study, encodes multiple colonization factors. Notable among them are aggregative adherence fimbriae (AAF/II) and a secreted antiaggregation protein (Aap). Deletion of aap is known to increase adherence, autoaggregation, and biofilm formation, so it was proposed that Aap counteracts AAF/II-mediated interactions. We hypothesized that Aap sterically masks heat-resistant agglutinin 1 (Hra1), an integral outer membrane protein recently identified as an accessory colonization factor. We propose that this masking accounts for reduced in vivo colonization upon hra1 deletion and yet no colonization-associated phenotypes when hra1 is deleted in vitro. Using single and double mutants of hra1, aap, and the AAF/II structural protein gene aafA, we demonstrated that increased adherence in aap mutants occurs even when AAF/II proteins are genetically or chemically removed. Deletion of hra1 together with aap abolishes the hyperadherence phenotype, demonstrating that Aap indeed masks Hra1. The presence of all three colonization factors, however, is necessary for optimal colonization and for rapidly building stacked-brick patterns on slides and cultured monolayers, the signature EAEC phenotype. Altogether, our data demonstrate that Aap serves to mask nonstructural adhesins such as Hra1 and that optimal colonization by EAEC is mediated through interactions among multiple surface factors. IMPORTANCE Enteroaggregative Escherichia coli (EAEC) bacteria are exceptional colonizers of the human intestine and can cause diarrhea. Compared to other E. coli pathogens, little is known about the genes and pathogenic mechanisms that differentiate EAEC from harmless commensal E. coli. EAEC bacteria attach via multiple proteins and structures, including long appendages produced by assembling molecules of AafA and a short surface protein called Hra1. EAEC also secretes an antiadherence protein (Aap; also known as dispersin) which remains loosely attached to the cell surface. This report shows that dispersin covers Hra1 such that the adhesive properties of EAEC seen in the laboratory are largely produced by AafA structures. When the bacteria colonize worms, dispersin is sloughed off, or otherwise removed, such that Hra1-mediated adherence occurs. All three factors are required for optimal colonization, as well as to produce the signature EAEC stacked-brick adherence pattern. Interplay among multiple colonization factors may be an essential feature of exceptional colonizers.
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16
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Abstract
Many bacteria, both environmental and pathogenic, exhibit the property of autoaggregation. In autoaggregation (sometimes also called autoagglutination or flocculation), bacteria of the same type form multicellular clumps that eventually settle at the bottom of culture tubes. Autoaggregation is generally mediated by self-recognising surface structures, such as proteins and exopolysaccharides, which we term collectively as autoagglutinins. Although a widespread phenomenon, in most cases the function of autoaggregation is poorly understood, though there is evidence to show that aggregating bacteria are protected from environmental stresses or host responses. Autoaggregation is also often among the first steps in forming biofilms. Here, we review the current knowledge on autoaggregation, the role of autoaggregation in biofilm formation and pathogenesis, and molecular mechanisms leading to aggregation using specific examples.
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Affiliation(s)
- Thomas Trunk
- Bacterial Cell Surface Group, Section for Genetics and Evolutionary Biology, Department of Biosciences, University of Oslo, Oslo, Norway
| | - Hawzeen S Khalil
- Bacterial Cell Surface Group, Section for Genetics and Evolutionary Biology, Department of Biosciences, University of Oslo, Oslo, Norway
| | - Jack C Leo
- Bacterial Cell Surface Group, Section for Genetics and Evolutionary Biology, Department of Biosciences, University of Oslo, Oslo, Norway
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17
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Montero DA, Velasco J, Del Canto F, Puente JL, Padola NL, Rasko DA, Farfán M, Salazar JC, Vidal R. Locus of Adhesion and Autoaggregation (LAA), a pathogenicity island present in emerging Shiga Toxin-producing Escherichia coli strains. Sci Rep 2017; 7:7011. [PMID: 28765569 PMCID: PMC5539235 DOI: 10.1038/s41598-017-06999-y] [Citation(s) in RCA: 58] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2017] [Accepted: 06/22/2017] [Indexed: 02/03/2023] Open
Abstract
Shiga Toxin-producing Escherichia coli (STEC) are a group of foodborne pathogens associated with diarrhea, dysentery, hemorrhagic colitis (HC) and hemolytic uremic syndrome (HUS). Shiga toxins are the major virulence factor of these pathogens, however adhesion and colonization to the human intestine is required for STEC pathogenesis. A subset of STEC strains carry the Locus of Enterocyte Effacement (LEE) pathogenicity island (PAI), which encodes genes that mediate the colonization of the human intestine. While LEE-positive STEC strains have traditionally been associated with human disease, the burden of disease caused by STEC strains that lacks LEE (LEE-negative) has increased recently in several countries; however, in the absence of LEE, the molecular pathogenic mechanisms by STEC strains are unknown. Here we report a 86-kb mosaic PAI composed of four modules that encode 80 genes, including novel and known virulence factors associated with adherence and autoaggregation. Therefore, we named this PAI as Locus of Adhesion and Autoaggregation (LAA). Phylogenomic analysis using whole-genome sequences of STEC strains available in the NCBI database indicates that LAA PAI is exclusively present in a subset of emerging LEE-negative STEC strains, including strains isolated from HC and HUS cases. We suggest that the acquisition of this PAI is a recent evolutionary event, which may contribute to the emergence of these STEC.
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Affiliation(s)
- David A Montero
- Programa de Microbiología y Micología, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Juliana Velasco
- Servicio de Urgencia Infantil, Hospital Clínico de la Universidad de Chile "Dr. José Joaquín Aguirre", Santiago, Chile
| | - Felipe Del Canto
- Programa de Microbiología y Micología, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Jose L Puente
- Departamento de Microbiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Mexico
| | - Nora L Padola
- Centro de Investigación Veterinaria Tandil, CONICET-CIC, Facultad de Ciencias Veterinarias, UNCPBA, Tandil, Argentina
| | - David A Rasko
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Mauricio Farfán
- Centro de Estudios Moleculares, Departamento de Pediatría, Hospital Dr. Luis Calvo Mackenna, Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Juan C Salazar
- Programa de Microbiología y Micología, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Roberto Vidal
- Programa de Microbiología y Micología, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Santiago, Chile.
- Instituto Milenio de Inmunología e Inmunoterapia, Facultad de Medicina, Universidad de Chile, Santiago, Chile.
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18
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Glaubman J, Hofmann J, Bonney ME, Park S, Thomas JM, Kokona B, Ramos Falcón LI, Chung YK, Fairman R, Okeke IN. Self-association motifs in the enteroaggregative Escherichia coli heat-resistant agglutinin 1. MICROBIOLOGY-SGM 2016; 162:1091-1102. [PMID: 27166217 DOI: 10.1099/mic.0.000303] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The heat-resistant agglutinin 1 (Hra1) is an integral outer membrane protein found in strains of Escherichia coli that are exceptional colonizers. Hra1 from enteroaggregative E. coli strain 042 is sufficient to confer adherence to human epithelial cells and to cause bacterial autoaggregation. Hra1 is closely related to the Tia invasin, which also confers adherence, but not autoaggregation. Here, we have demonstrated that Hra1 mediates autoaggregation by self-association and we hypothesize that at least some surface-exposed amino acid sequences that are present in Hra1, but absent in Tia, represent autoaggregation motifs. We inserted FLAG tags along the length of Hra1 and used immune-dot blots to verify that four in silico-predicted outer loops were indeed surface exposed. In Hra1 we swapped nine candidate motifs in three of these loops, ranging from one to ten amino acids in length, to the corresponding sequences in Tia. Three of the motifs were required for Hra1-mediated autoaggregation. The database was searched for other surface proteins containing these motifs; the GGXWRDDXK motif was also present in a surface-exposed region of Rck, a Salmonella enterica serotype Typhimurium complement resistance protein. Cloning and site-specific mutagenesis demonstrated that Rck can confer weak, GGXWRDDXK-dependent autoaggregation by self-association. Hra1 and Rck appear to form heterologous associations and GGXWRDDXK is required on both molecules for Hra1-Rck association. However, a GGYWRDDLKE peptide was not sufficient to interfere with Hra1-mediated autoaggregation. In the present study, three autoaggregation motifs in an integral outer membrane protein have been identified and it was demonstrated that at least one of them works in the context of a different cell surface.
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Affiliation(s)
| | | | - Megan E Bonney
- Department of Biology, Haverford College, Haverford, PA, USA
| | - Sumin Park
- Department of Biology, Haverford College, Haverford, PA, USA
| | | | - Bashkim Kokona
- Department of Biology, Haverford College, Haverford, PA, USA
| | | | - Yoonjie K Chung
- Department of Biology, Haverford College, Haverford, PA, USA
| | - Robert Fairman
- Department of Biology, Haverford College, Haverford, PA, USA
| | - Iruka N Okeke
- Department of Biology, Haverford College, Haverford, PA, USA
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Kassé FN, Fairbrother JM, Dubuc J. Relationship between Escherichia coli virulence factors and postpartum metritis in dairy cows. J Dairy Sci 2016; 99:4656-4667. [PMID: 27016836 DOI: 10.3168/jds.2015-10094] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2015] [Accepted: 02/09/2016] [Indexed: 11/19/2022]
Abstract
The objectives of this study were to report the prevalence of Escherichia coli and Trueperella pyogenes in the uterus of postpartum dairy cows before the onset of postpartum metritis (PPM) and to quantify their association with subsequent occurrence of PPM, to quantify the association between the presence of genes encoding E. coli virulence factors (VF) and PPM, and to determine the accuracy of using early postpartum uterine bacteriology results (bacteria and VF) to identify cows at risk of PPM. A prospective cohort study was conducted on 3 commercial dairy farms. Uterine swabs were collected from 371 Holstein dairy cows (3 commercial herds) at 1 to 7d in milk and submitted to the laboratory for identification of E. coli, T. pyogenes, and E. coli VF. A total of 40 VF were tested using the radioactive probe hybridization method. Postpartum metritis was defined as the presence of a fetid watery red-brown uterine discharge, associated with fever (rectal temperature >39.5°C), and systemic signs of illness (dullness, reduced appetite, and milk production). Surveillance of PPM was done by trained farmers blinded to laboratory results and cows were followed until 21d in milk. Statistical analyses were conducted using 2×2 tables and mixed logistical regression models. Prevalences of E. coli, T. pyogenes, and PPM were 42, 34, and 15%, respectively. A total of 32 VF were found in E. coli isolates. Most prevalent VF were extraintestinal pathogenic genes such as fimH (89%), hlyE (87%), and iss (70%). Cows positive for intrauterine E. coli were 3.2 times more likely to have subsequent PPM compared with bacteriologically negative cows. Cows with VF hra1 in their uterus were 2.7 times more likely to have PPM than cows positive for E. coli and negative for hra1 and 5.9 times more likely than bacteriologically negative cows. Cows with VF kpsMTII in their uterus were 3.2 times more likely to have PPM than cows positive for E. coli and negative for kpsMTII and 6.2 times more likely than bacteriologically negative cows. Using E. coli, hra1, and kpsMTII as predictors for subsequent PPM, positive predictive values were 23, 31, and 42%, respectively, whereas the negative predictive values were 91, 80, and 78%, respectively. Overall, these results showed that E. coli and some VF were associated with PPM.
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Affiliation(s)
- F N Kassé
- OIE Reference Laboratory for Escherichia coli (EcL), Faculté de médecine vétérinaire, C.P. 5000, St-Hyacinthe, QC, J2S 7C6, Canada
| | - J M Fairbrother
- OIE Reference Laboratory for Escherichia coli (EcL), Faculté de médecine vétérinaire, C.P. 5000, St-Hyacinthe, QC, J2S 7C6, Canada
| | - J Dubuc
- Département de sciences cliniques, Faculté de médecine vétérinaire, Université de Montréal, C.P. 5000, St-Hyacinthe, QC, J2S 7C6, Canada.
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20
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Skurnik D, Clermont O, Guillard T, Launay A, Danilchanka O, Pons S, Diancourt L, Lebreton F, Kadlec K, Roux D, Jiang D, Dion S, Aschard H, Denamur M, Cywes-Bentley C, Schwarz S, Tenaillon O, Andremont A, Picard B, Mekalanos J, Brisse S, Denamur E. Emergence of Antimicrobial-Resistant Escherichia coli of Animal Origin Spreading in Humans. Mol Biol Evol 2015; 33:898-914. [PMID: 26613786 DOI: 10.1093/molbev/msv280] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
In the context of the great concern about the impact of human activities on the environment, we studied 403 commensal Escherichia coli/Escherichia clade strains isolated from several animal and human populations that have variable contacts to one another. Multilocus sequence typing (MLST) showed a decrease of diversity 1) in strains isolated from animals that had an increasing contact with humans and 2) in all strains that had increased antimicrobial resistance. A specific B1 phylogroup clonal complex (CC87, Institut Pasteur schema nomenclature) of animal origin was identified and characterized as being responsible for the increased antimicrobial resistance prevalence observed in strains from the environments with a high human-mediated antimicrobial pressure. CC87 strains have a high capacity of acquiring and disseminating resistance genes with specific metabolic and genetic determinants as demonstrated by high-throughput sequencing and phenotyping. They are good mouse gut colonizers but are not virulent. Our data confirm the predominant role of human activities in the emergence of antimicrobial resistance in the environmental bacterial strains and unveil a particular E. coli clonal complex of animal origin capable of spreading antimicrobial resistance to other members of microbial communities.
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Affiliation(s)
- David Skurnik
- Division of Infectious Diseases, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA INSERM, IAME, UMR 1137, Paris, France Univ Paris Diderot, IAME, Sorbonne Paris Cité, UMR 1137, Faculté De Médecine, Site Xavier Bichat, Paris, France French National Reference Center for Bacterial Resistance in Commensal Flora, Laboratory of Bacteriology, Bichat-Claude Bernard Hospital, Assistance Publique-Hôpitaux De Paris, Paris, France
| | - Olivier Clermont
- INSERM, IAME, UMR 1137, Paris, France Univ Paris Diderot, IAME, Sorbonne Paris Cité, UMR 1137, Faculté De Médecine, Site Xavier Bichat, Paris, France
| | - Thomas Guillard
- Division of Infectious Diseases, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA
| | - Adrien Launay
- INSERM, IAME, UMR 1137, Paris, France Univ Paris Diderot, IAME, Sorbonne Paris Cité, UMR 1137, Faculté De Médecine, Site Xavier Bichat, Paris, France
| | | | - Stéphanie Pons
- Division of Infectious Diseases, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA
| | - Laure Diancourt
- Institut Pasteur, Genotyping of Pathogens and Public Health, Paris, France
| | | | - Kristina Kadlec
- Institute of Farm Animal Genetics, Friedrich-Loeffler-Institut (FLI), Neustadt-Mariensee, Germany
| | - Damien Roux
- Division of Infectious Diseases, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA INSERM, IAME, UMR 1137, Paris, France Univ Paris Diderot, IAME, Sorbonne Paris Cité, UMR 1137, Faculté De Médecine, Site Xavier Bichat, Paris, France
| | - Deming Jiang
- Division of Infectious Diseases, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA
| | - Sara Dion
- INSERM, IAME, UMR 1137, Paris, France Univ Paris Diderot, IAME, Sorbonne Paris Cité, UMR 1137, Faculté De Médecine, Site Xavier Bichat, Paris, France
| | | | - Maurice Denamur
- INSERM, IAME, UMR 1137, Paris, France Univ Paris Diderot, IAME, Sorbonne Paris Cité, UMR 1137, Faculté De Médecine, Site Xavier Bichat, Paris, France
| | - Colette Cywes-Bentley
- Division of Infectious Diseases, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA
| | - Stefan Schwarz
- Institute of Farm Animal Genetics, Friedrich-Loeffler-Institut (FLI), Neustadt-Mariensee, Germany
| | - Olivier Tenaillon
- INSERM, IAME, UMR 1137, Paris, France Univ Paris Diderot, IAME, Sorbonne Paris Cité, UMR 1137, Faculté De Médecine, Site Xavier Bichat, Paris, France
| | - Antoine Andremont
- INSERM, IAME, UMR 1137, Paris, France Univ Paris Diderot, IAME, Sorbonne Paris Cité, UMR 1137, Faculté De Médecine, Site Xavier Bichat, Paris, France French National Reference Center for Bacterial Resistance in Commensal Flora, Laboratory of Bacteriology, Bichat-Claude Bernard Hospital, Assistance Publique-Hôpitaux De Paris, Paris, France
| | - Bertrand Picard
- INSERM, IAME, UMR 1137, Paris, France Univ Paris Nord, Sorbonne Paris Cité, UMR 1137, Faculté De Médecine, Site Xavier Bichat, Paris, France
| | | | - Sylvain Brisse
- Institut Pasteur, Genotyping of Pathogens and Public Health, Paris, France
| | - Erick Denamur
- INSERM, IAME, UMR 1137, Paris, France Univ Paris Diderot, IAME, Sorbonne Paris Cité, UMR 1137, Faculté De Médecine, Site Xavier Bichat, Paris, France
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21
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Tymensen LD, Pyrdok F, Coles D, Koning W, McAllister TA, Jokinen CC, Dowd SE, Neumann NF. Comparative accessory gene fingerprinting of surface water Escherichia coli reveals genetically diverse naturalized population. J Appl Microbiol 2015; 119:263-77. [PMID: 25816691 DOI: 10.1111/jam.12814] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2015] [Revised: 03/16/2015] [Accepted: 03/20/2015] [Indexed: 12/16/2022]
Abstract
AIMS To utilize comparative accessory gene fingerprinting to discriminate between naturalized and faecal Escherichia coli, with particular emphasis on strains from phylogroup B1. METHODS AND RESULTS Fourteen accessory genes that were potentially ecotype-specific were selected on the basis of comparative genomic DNA sequence analysis between faecal and environmental strains and also using a literature-based strategy. PCR assays were designed for each gene, and used to screen 107 faecal strains from various hosts and 106 environmental strains from surface water and sediment. While none of the 14 accessory genes were ecotype-specific, six of the genes were ecotype-enriched. Specifically, toxin-antitoxin system genes were more abundant among faecal strains, whereas genes involved in iron acquisition, complement resistance/surface exclusion, and biofilm formation were more abundant among environmental strains. These six genes were used to form composite fingerprints which revealed the presence of several ecotype-specific and -enriched fingerprints. Notably, some of the environmental strain-specific or -enriched fingerprints consisted of strains putatively belonging to clade ET-1, which has been previously recognized as a naturalized subpopulation. CONCLUSIONS Unlike single genes which did not reliably distinguish between faecal and naturalized phylogroup B1 E. coli strains, composite fingerprints of ecotype-enriched accessory genes may offer a novel method for distinguishing between these two populations. SIGNIFICANCE AND IMPACT OF THE STUDY Accessory gene fingerprinting may have important practical implications for improving the specificity of methods that are widely used for quantifying and identifying the sources of faecal contamination in surface water.
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Affiliation(s)
- L D Tymensen
- Alberta Agriculture and Rural Development, Lethbridge, AB, Canada
| | - F Pyrdok
- Umwelt-und Ingenieurtechnik GmbH, Dresden, Germany
| | - D Coles
- Alberta Agriculture and Rural Development, Lethbridge, AB, Canada
| | - W Koning
- Alberta Environment and Sustainable Resource Development, Calgary, AB, Canada
| | - T A McAllister
- Agriculture and Agri-Food Canada, Lethbridge, AB, Canada
| | - C C Jokinen
- Alberta Agriculture and Rural Development, Lethbridge, AB, Canada
| | - S E Dowd
- Molecular Research LP, Shallowater, TX, USA
| | - N F Neumann
- Department of Public Health Sciences, University of Alberta, Edmonton, AB, Canada
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22
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Epidemiology and clinical manifestations of enteroaggregative Escherichia coli. Clin Microbiol Rev 2015; 27:614-30. [PMID: 24982324 DOI: 10.1128/cmr.00112-13] [Citation(s) in RCA: 129] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Enteroaggregative Escherichia coli (EAEC) represents a heterogeneous group of E. coli strains. The pathogenicity and clinical relevance of these bacteria are still controversial. In this review, we describe the clinical significance of EAEC regarding patterns of infection in humans, transmission, reservoirs, and symptoms. Manifestations associated with EAEC infection include watery diarrhea, mucoid diarrhea, low-grade fever, nausea, tenesmus, and borborygmi. In early studies, EAEC was considered to be an opportunistic pathogen associated with diarrhea in HIV patients and in malnourished children in developing countries. In recent studies, associations with traveler's diarrhea, the occurrence of diarrhea cases in industrialized countries, and outbreaks of diarrhea in Europe and Asia have been reported. In the spring of 2011, a large outbreak of hemolytic-uremic syndrome (HUS) and hemorrhagic colitis occurred in Germany due to an EAEC O104:H4 strain, causing 54 deaths and 855 cases of HUS. This strain produces the potent Shiga toxin along with the aggregative fimbriae. An outbreak of urinary tract infection associated with EAEC in Copenhagen, Denmark, occurred in 1991; this involved extensive production of biofilm, an important characteristic of the pathogenicity of EAEC. However, the heterogeneity of EAEC continues to complicate diagnostics and also our understanding of pathogenicity.
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23
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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: 831] [Impact Index Per Article: 75.5] [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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24
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Genotypic and phenotypic characterisation of enteroaggregative Escherichia coli from children in Rio de Janeiro, Brazil. PLoS One 2013; 8:e69971. [PMID: 23936127 PMCID: PMC3728331 DOI: 10.1371/journal.pone.0069971] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2013] [Accepted: 06/13/2013] [Indexed: 11/22/2022] Open
Abstract
Enteroaggregative Escherichia coli (EAEC) is a significant cause of diarrhoeal illness in both children and adults. Genetic heterogeneity and recovery of EAEC strains from both healthy and diseased individuals complicates our understanding of EAEC pathogenesis. We wished to establish if genetic or phenotypic attributes could be used to distinguish between strains asymptomatically colonising healthy individuals and those which cause disease. Genotypic screening of a collection of twenty four EAEC isolates from children with and without diarrhoea revealed no significant differences in the repertoire of putative virulence factors present in either group of strains. In contrast, EAEC strains from phylogroup A were more strongly associated with asymptomatic groups whereas strains from phylogroup D were more associated with cases of diarrhoea. Phenotypic screening revealed no differences in the ability of strains from either cohort of children to form biofilms, to adhere to and invade cells in tissue culture or to cause disease in the Caenorhabditis elegans model of infection. However, the latter assay did reveal significant reduction in nematode killing rates when specific virulence factors were deleted from human pathogenic strains. Our results suggest that current models of infection are not useful for distinguishing avirulent from pathogenic strains of EAEC but can be useful in studying the effect of specific virulence factors.
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25
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Pereira MDGC, Byrne BA, Nguyen TB, Lewis DJ, Atwill ER. The occurrence of subtilase-cytotoxin-encoding genes in environmental Escherichia coli isolated from a Northern California estuary. Can J Microbiol 2013; 59:437-41. [DOI: 10.1139/cjm-2012-0606] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The presence of subtilase-cytotoxin-encoding genes was determined in 397 environmental Escherichia coli strains isolated from water, suspended solids, and sediments sampled from different hydrological and environmental conditions in a California estuary. A total of 7 strains (1.76%) were found to harbor subtilase-cytotoxin-encoding genes. Using primers targeting subA only, we generated PCR amplicons from 2 strains; while using primers targeting the 3′ end of SubA downstream to the 5′ end of SubB, amplicons of 232 bp were generated from 5 additional strains. The 556 bp subA sequences were almost identical to that in the subtilase-cytotoxin-positive strain ED 591 (98%), while subAB sequences of 2 non-Shiga-toxigenic strains revealed 100% similarity with the Shiga-toxigenic E. coli O113:H21 strain 98NK2 that was isolated from an outbreak of hemolytic uremic syndrome. Additionally, the serogroup O113:H21 was present in this collection of environmental E. coli, and it was found to harbor stx2d, hra1 that encodes the heat resistant agglutinin 1, and a subAB sequence similar to that in the non-Shiga-toxigenic E. coli subtilase cytotoxin strain ED 591. To further understand potential health risks posed by strains encoding SubAB, future epidemiological studies should consider screening isolates for subAB regardless of the presence of Shiga-toxin-encoding genes.
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Affiliation(s)
- Maria das Graças C. Pereira
- Department of Population Health and Reproduction, School of Veterinary Medicine, 2012 Haring Hall, University of California, Davis, CA 95616, USA
| | - Barbara A. Byrne
- Department of Pathology, Microbiology and Immunology, School of Veterinary Medicine, 4206 VM3A, University of California, Davis, CA 95616, USA
| | - Trân B.H. Nguyen
- Department of Population Health and Reproduction, School of Veterinary Medicine, 1089 Veterinary Medicine Drive, University of California, Davis, CA 95616, USA
| | - David J. Lewis
- University of California Cooperative Extension - Marin, 1682 Novato Boulevard, Suite 150B, Novato, CA 94947, USA
| | - E. Robert Atwill
- Western Institute for Food Safety and Security, 1089 Veterinary Medicine Drive, University of California, Davis, CA 95616, USA
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26
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Jafari A, Aslani MM, Bouzari S. Enteroaggregative Escherichia coli, a heterogenous, underestimated and under-diagnosed E. coli pathotype in Iran. GASTROENTEROLOGY AND HEPATOLOGY FROM BED TO BENCH 2013; 6:71-9. [PMID: 24834248 PMCID: PMC4017499] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Subscribe] [Scholar Register] [Received: 01/15/2013] [Accepted: 03/10/2013] [Indexed: 11/17/2022]
Abstract
The main features of enteroaggregative Escherichia coli (EAEC) pathogenesis include attachment of bacteria to the intestinal mucosa, production of various toxins and cytotoxins, and stimulation of mucosal inflammation. 'Virulence' genes encode these features. Comparison of different EAEC isolates has shown that the virulence gene content of these isolates varies considerably. The heterogeneity of EAEC strains was concluded from the results obtained from the volunteer as well as other studies. Although the underlying mechanism behind the apparent increase in O104:H4 virulence is not known, several bacterial factors have been implicated. In this review, the known virulence factors involved in pathogenesis of EAEC pathotype are summarized.
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Affiliation(s)
- Anis Jafari
- Molecular Biology Unit, Pasteur Institute of Iran, Tehran, Iran,Escherichia coli Reference Laboratory, Molecular Biology Unit, Pasteur Institute of Iran, Tehran, Iran
| | | | - Saeid Bouzari
- Molecular Biology Unit, Pasteur Institute of Iran, Tehran, Iran,Escherichia coli Reference Laboratory, Molecular Biology Unit, Pasteur Institute of Iran, Tehran, Iran
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27
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Estrada-Garcia T, Navarro-Garcia F. Enteroaggregative Escherichia coli pathotype: a genetically heterogeneous emerging foodborne enteropathogen. ACTA ACUST UNITED AC 2012; 66:281-98. [PMID: 22775224 DOI: 10.1111/j.1574-695x.2012.01008.x] [Citation(s) in RCA: 89] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2012] [Revised: 07/03/2012] [Accepted: 07/03/2012] [Indexed: 11/28/2022]
Abstract
Until now, a common feature that defines the enteroaggregative Escherichia coli (EAEC) strains is the ability to produce a 'stacked-brick' appearance on epithelial cells, but it does not distinguish between pathogenic and nonpathogenic strains. Numerous adhesins, toxins, and proteins associated with virulence have been described, as well as multiple factors contributing to EAEC-induced inflammation. None of these factors are found in all EAEC isolates, and no single factor has ever been implicated in EAEC virulence. The European outbreak of Shiga-toxin-producing EAEC raises its pathogenic potential and interest on finding the true pathogenic factors that may define this pathotype. EAEC were first associated with persistent diarrhea in infants from developing countries, since then they have increasingly been linked as a cause of acute and persistent diarrhea in young infants and children in developing and industrialized countries, individuals infected with human immunodeficiency virus, as a cause of acute diarrhea in travelers from industrialized regions, and with foodborne outbreaks. A major effect of EAEC infection is on the malnourished children in developing countries. Here, we will discuss the EAEC public health relevance and their complexity because of the strain heterogeneity regarding their pathogenesis, identification, diagnosis, lineage, epidemiology, and clinical manifestations.
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Affiliation(s)
- Teresa Estrada-Garcia
- Department of Molecular Biomedicine, Centro de Investigación y de Estudios Avanzados del IPN, México DF, Mexico
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28
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The heat-resistant agglutinin family includes a novel adhesin from enteroaggregative Escherichia coli strain 60A. J Bacteriol 2011; 193:4813-20. [PMID: 21764925 DOI: 10.1128/jb.05142-11] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Heat-resistant agglutinin 1 (Hra1) is an accessory colonization factor of enteroaggregative Escherichia coli (EAEC) strain 042. Tia, a close homolog of Hra1, is an invasin and adhesin that has been described in enterotoxigenic E. coli. We devised a PCR-restriction fragment length polymorphism screen for the associated genes and found that they occur among 55 (36.7%) of the enteroaggregative E. coli isolates screened, as well as lower proportions of enterotoxigenic, enteropathogenic, enterohemorrhagic, and commensal E. coli isolates. Overall, 25%, 8%, and 3% of 150 EAEC strains harbored hra1 alone, tia alone, or both genes, respectively. One EAEC isolate, 60A, produced an amplicon with a unique restriction profile, distinct from those of hra1 and tia. We cloned and sequenced the full-length agglutinin gene from strain 60A and have designated it hra2. The hra2 gene was not detected in any of 257 diarrheagenic E. coli isolates in our collection but is present in the genome of Salmonella enterica serovar Heidelberg strain SL476. The cloned hra2 gene from strain 60A, which encodes a predicted amino acid sequence that is 64% identical to that of Hra1 and 68% identical to that of Tia, was sufficient to confer adherence on E. coli K-12. We constructed an hra2 deletion mutant of EAEC strain 60A. The mutant was deficient in adherence but not autoaggregation or invasion, pointing to a functional distinction from the autoagglutinin Hra1 and the Tia invasin. Hra1, Tia, and the novel accessory adhesin Hra2 are members of a family of integral outer membrane proteins that confer different colonization-associated phenotypes.
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Okeke IN, Wallace-Gadsden F, Simons HR, Matthews N, Labar AS, Hwang J, Wain J. Multi-locus sequence typing of enteroaggregative Escherichia coli isolates from Nigerian children uncovers multiple lineages. PLoS One 2010; 5:e14093. [PMID: 21124856 PMCID: PMC2990770 DOI: 10.1371/journal.pone.0014093] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2010] [Accepted: 11/04/2010] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Enteroaggregative Escherichia coli (EAEC) are defined by their stacked-brick adherence pattern to human epithelial cells. There is no all-encompassing genetic marker for EAEC. The category is commonly implicated in diarrhea but research is hampered by perplexing heterogeneity. METHODOLOGY/PRINCIPAL FINDINGS To identify key EAEC lineages, we applied multilocus sequence typing to 126 E. coli isolates from a Nigerian case-control study that showed aggregative adherence in the HEp-2 adherence assay, and 24 other EAEC strains from diverse locations. EAEC largely belonged to the A, B1 and D phylogenetic groups and only 7 (4.6%) isolates were in the B2 cluster. As many as 96 sequence types (STs) were identified but 60 (40%) of the EAEC strains belong to or are double locus variants of STs 10, 31, and 394. The remainder did not belong to predominant complexes. The most common ST complex, with predicted ancestor ST10, included 32 (21.3%) of the isolates. Significant age-related distribution suggests that weaned children in Nigeria are at risk for diarrhea from of ST10-complex EAEC. Phylogenetic group D EAEC strains, predominantly from ST31- and ST394 complexes, represented 38 (25.3%) of all isolates, include genome-sequenced strain 042, and possessed conserved chromosomal loci. CONCLUSIONS/SIGNIFICANCE We have developed a molecular phylogenetic framework, which demonstrates that although grouped by a shared phenotype, the category of 'EAEC' encompasses multiple pathogenic lineages. Principal among isolates from Nigeria were ST10-complex EAEC that were associated with diarrhea in children over one year and ECOR D strains that share horizontally acquired loci.
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Affiliation(s)
- Iruka N Okeke
- Department of Biology, Haverford College, Haverford, Pennsylvania, USA.
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A pathoadaptive deletion in an enteroaggregative Escherichia coli outbreak strain enhances virulence in a Caenorhabditis elegans model. Infect Immun 2010; 78:4068-76. [PMID: 20584976 DOI: 10.1128/iai.00014-10] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Enteroaggregative Escherichia coli (EAEC) strains are important diarrheal pathogens. EAEC strains are defined by their characteristic stacked-brick pattern of adherence to epithelial cells but show heterogeneous virulence and have different combinations of adhesin and toxin genes. Pathoadaptive deletions in the lysine decarboxylase (cad) genes have been noted among hypervirulent E. coli subtypes of Shigella and enterohemorrhagic E. coli. To test the hypothesis that cad deletions might account for heterogeneity in EAEC virulence, we developed a Caenorhabditis elegans pathogenesis model. Well-characterized EAEC strains were shown to colonize and kill C. elegans, and differences in virulence could be measured quantitatively. Of 49 EAEC strains screened for lysine decarboxylase activity, 3 tested negative. Most notable is isolate 101-1, which was recovered in Japan, from the largest documented EAEC outbreak. EAEC strain 101-1 was unable to decarboxylate lysine in vitro due to deletions in cadA and cadC, which, respectively, encode lysine decarboxylase and a transcriptional activator of the cadAB genes. Strain 101-1 was significantly more lethal to C. elegans than control strain OP50. Lethality was attenuated when the lysine decarboxylase defect was complemented from a multicopy plasmid and in single copy. In addition, restoring lysine decarboxylase function produced derivatives of 101-1 deficient in aggregative adherence to cultured human epithelial cells. Lysine decarboxylase inactivation is pathoadapative in an important EAEC outbreak strain, and deletion of cad genes could produce hypervirulent EAEC lineages in the future. These results suggest that loss, as well as gain, of genetic material can account for heterogeneous virulence among EAEC strains.
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Vejborg RM, Friis C, Hancock V, Schembri MA, Klemm P. A virulent parent with probiotic progeny: comparative genomics of Escherichia coli strains CFT073, Nissle 1917 and ABU 83972. Mol Genet Genomics 2010; 283:469-84. [PMID: 20354866 DOI: 10.1007/s00438-010-0532-9] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2010] [Accepted: 03/08/2010] [Indexed: 12/24/2022]
Abstract
Escherichia coli is a highly versatile species encompassing a diverse spectrum of strains, i.e. from highly virulent isolates causing serious infectious diseases to commensals and probiotic strains. Although much is known about bacterial pathogenicity in E. coli, the understanding of which genetic determinants differentiates a virulent from an avirulent strain still remains limited. In this study we designed a new comparative genomic hybridization microarray based on 31 sequenced E. coli strains and used it to compare two E. coli strains used as prophylactic agents (i.e. Nissle 1917 and 83972) with the highly virulent uropathogen CFT073. Only relatively minor genetic variations were found between the isolates, suggesting that the three strains may have originated from the same virulent ancestral parent. Interestingly, Nissle 1917 (a gut commensal strain) was more similar to CFT073 with respect to genotype and phenotype than 83972 (an asymptomatic bacteriuria strain). The study indicates that genetic variations (e.g. mutations) and expression differences, rather than genomic content per se, contribute to the divergence in disease-causing ability between these strains. This has implications for the use of virulence factors in epidemiological research, and emphasizes the need for more comparative genomic studies of closely related strains to compare their virulence potential.
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