Enteroaggregative Escherichia coli strains among classical enteropathogenic Escherichia coli O serogroups.
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ABSTRACT:
SUBMITTER: Elias WP
PROVIDER: S-EPMC130765 | biostudies-literature | 2002 Sep
REPOSITORIES: biostudies-literature
Publications
Enteroaggregative Escherichia coli strains among classical enteropathogenic Escherichia coli O serogroups.
Elias Waldir P WP Barros Samar F SF Moreira Cristiano G CG Trabulsi Luiz R LR Gomes Tânia A T TA
Journal of clinical microbiology 20020901 9
Similar Datasets
Project description:We describe two serogroup O157 Escherichia coli strains from Brazilian infants with diarrhea. A variety of assays indicate that these strains belong to the enteropathogenic, not the enterohemorrhagic, pathotype. These strains possess a novel bfpA allele encoding the type IV pilin characteristic of typical enteropathogenic E. coli strains. Our results emphasize the pitfalls of classifying pathogenic E. coli by serogroup.
| S-EPMC2873750 | biostudies-literature
Project description:Although enteroaggregative E. coli (EAEC) has been implicated as a common cause of diarrhea in multiple settings, neither its essential genomic nature nor its role as an enteric pathogen are fully understood. The current definition of this pathotype requires demonstration of cellular adherence; a working molecular definition encompasses E. coli which do not harbor the heat-stable or heat-labile toxins of enterotoxigenic E. coli (ETEC) and harbor the genes aaiC, aggR, and/or aatA. In an effort to improve the definition of this pathotype, we report the most definitive characterization of the pan-genome of EAEC to date, applying comparative genomics and functional characterization on a collection of 97 EAEC strains isolated in the course of a multicenter case-control diarrhea study (Global Enteric Multi-Center Study, GEMS). Genomic analysis revealed that the EAEC strains mapped to all phylogenomic groups of E. coli. Circa 70% of strains harbored one of the five described AAF variants; there were no additional AAF variants identified, and strains that lacked an identifiable AAF generally did not have an otherwise complete AggR regulon. An exception was strains that harbored an ETEC colonization factor (CF) CS22, like AAF a member of the chaperone-usher family of adhesins, but not phylogenetically related to the AAF family. Of all genes scored, sepA yielded the strongest association with diarrhea (P = 0.002) followed by the increased serum survival gene, iss (p = 0.026), and the outer membrane protease gene ompT (p = 0.046). Notably, the EAEC genomes harbored several genes characteristically associated with other E. coli pathotypes. Our data suggest that a molecular definition of EAEC could comprise E. coli strains harboring AggR and a complete AAF(I-V) or CS22 gene cluster. Further, it is possible that strains meeting this definition could be both enteric bacteria and urinary/systemic pathogens.
| S-EPMC7500659 | biostudies-literature
Project description:Epithelial cell migration is an essential response to enteric pathogens such as enteropathogenic Escherichia coli (EPEC). This study aimed to investigate the effects of EPEC infection on intestinal epithelial cell migration in vitro, as well as the involvement of type III secretion system (T3SS) and Rho GTPases. Crypt intestinal epithelial cells (IEC-6) were infected with EPEC strains (E2348/69, ΔescF, and the LDI001 strain isolated from a malnourished Brazilian child) and commensal E. coli HS. Wound migration and cell death assays were performed at different time-points. Transcription and expression of Rho GTPases were evaluated using real-time PCR and western blotting. Overall, EPEC E2348/69 reduced migration and increased apoptosis and necrosis levels compared to EPEC LDI001 and E. coli HS strains. Moreover, EPEC LDI001 impaired cell migration at a higher level than E. coli HS and increased necrosis after 24 hours compared to the control group. The different profiles of virulence genes between the two wild-type EPEC strains, characterized by the absence of espL and nleE genes in the LDI001, might explain the phenotypic results, playing significant roles on cell migration impairment and cell death-related events. Moreover, the type III secretion system is determinant for the inhibition of intestinal epithelial cell migration by EPEC 2348/69, as its deletion prevented the effect. Active Rac1 concentrations were increased in E2348/69 and LDI001-infected cells, while the T3SS-deficient strain did not demonstrate this activation. This study contributes with valuable insight to characterize the mechanisms involved in the impairment of intestinal cell migration induced by EPEC.
| S-EPMC6065879 | biostudies-literature
Project description: Not available
| S-EPMC4178420 | biostudies-literature
Project description:BackgroundEnteropathogenic (EPEC) and Enteroaggregative (EAEC) E. coli have similar, but distinct clinical symptoms and modes of pathogenesis. Nevertheless when they infect the gastrointestinal tract, it is thought that their flagellin causes IL-8 release leading to neutrophil recruitment and gastroenteritis. However, this may not be the whole story as the effect of bacterial adherence to IEC innate response(s) remains unclear. Therefore, we have characterized which bacterial motifs contribute to the innate epithelial response to EPEC and EAEC, using a range of EPEC and EAEC isogenic mutant strains.MethodologyCaco-2 and HEp-2 cell lines were exposed to prototypical EPEC strain E2348/69 or EAEC strain O42, in addition to a range of isogenic mutant strains. E69 [LPS, non-motile, non-adherent, type three secretion system (TTSS) negative, signalling negative] or O42 [non-motile, non-adherent]. IL-8 and CCL20 protein secretion was measured. Bacterial surface structures were assessed by negative staining Transmission Electron Microscopy. The Fluorescent-actin staining test was carried out to determine bacterial adherence.ResultsPrevious studies have reported a balance between the host pro-inflammatory response and microbial suppression of this response. In our system an overall balance towards the host pro-inflammatory response is seen with the E69 WT and to a greater extent O42 WT, which is in fit with clinical symptoms. On removal of the external EPEC structures flagella, LPS, BFP, EspA and EspC; and EAEC flagella and AAF, the host inflammatory response is reduced. However, removal of E69 lymphostatin increases the host inflammatory response suggesting involvement in the bacterial mediated anti-inflammatory response.ConclusionEpithelial responses were due to combinations of bacterial agonists, with host-bacterial contact a key determinant of these innate responses. Host epithelial recognition was offset by the microbe's ability to down-regulate the inflammatory response. Understanding the complexity of this host-microbial balance will contribute to improved vaccine design for infectious gastroenteritis.
| S-EPMC3203933 | biostudies-literature
Project description:Escherichia coli O145 strains RM14715 and RM14723 were isolated from wildlife feces near a leafy greens-growing region in Yuma, Arizona. Both strains carry a distinct genotype compared with the E. coli O145 strains isolated from Salinas Valley, California. Here we report complete genome sequences and annotations of RM14715 and RM14723.
| S-EPMC5946043 | biostudies-literature
Project description:BackgroundEnteroaggregative Haemorrhagic E. coli (EAHEC) is a new pathogenic group of E. coli characterized by the presence of a vtx2-phage integrated in the genomic backbone of Enteroaggregative E. coli (EAggEC). So far, four distinct EAHEC serotypes have been described that caused, beside the large outbreak of infection occurred in Germany in 2011, a small outbreak and six sporadic cases of HUS in the time span 1992-2012. In the present work we determined the whole genome sequence of the vtx2-phage, termed Phi-191, present in the first described EAHEC O111:H2 isolated in France in 1992 and compared it with those of the vtx-phages whose sequences were available.ResultsThe whole genome sequence of the Phi-191 phage was identical to that of the vtx2-phage P13374 present in the EAHEC O104:H4 strain isolated during the German outbreak 20 years later. Moreover, it was also almost identical to those of the other vtx2-phages of EAHEC O104:H4 strains described so far. Conversely, the Phi-191 phage appeared to be different from the vtx2-phage carried by the EAHEC O111:H21 isolated in the Northern Ireland in 2012.The comparison of the vtx2-phages sequences from EAHEC strains with those from the vtx-phages of typical Verocytotoxin-producing E. coli strains showed the presence of a 900 bp sequence uniquely associated with EAHEC phages and encoding a tail fiber.ConclusionsAt least two different vtx2-phages, both characterized by the presence of a peculiar tail fiber-coding gene, intervened in the emergence of EAHEC. The finding of an identical vtx2-phage in two EAggEC strains isolated after 20 years in spite of the high variability described for vtx-phages is unexpected and suggests that such vtx2-phages are kept under a strong selective pressure.The observation that different EAHEC infections have been traced back to countries where EAggEC infections are endemic and the treatment of human sewage is often ineffective suggests that such countries may represent the cradle for the emergence of the EAHEC pathotype. In these regions, EAggEC of human origin can extensively contaminate the environment where they can meet free vtx-phages likely spread by ruminants excreta.
| S-EPMC4122784 | biostudies-literature
Project description:Enteropathogenic Escherichia coli (EPEC) strains that carry the EPEC adherence factor (EAF) plasmid were screened for the presence of different EAF sequences, including those of the plasmid-encoded regulator (per). Considerable variation in gene content of EAF plasmids from different strains was seen. However, bfpA, the gene encoding the structural subunit for the bundle-forming pilus, bundlin, and per genes were found in 96.8% of strains. Sequence analysis of the per operon and its promoter region from 15 representative strains revealed that it is highly conserved. Most of the variation occurs in the 5' two-thirds of the perA gene. In contrast, the C-terminal portion of the predicted PerA protein that contains the DNA-binding helix-turn-helix motif is 100% conserved in all strains that possess a full-length gene. In a minority of strains including the O119:H2 and canine isolates and in a subset of O128:H2 and O142:H6 strains, frameshift mutations in perA leading to premature truncation and consequent inactivation of the gene were identified. Cloned perA, -B, and -C genes from these strains, unlike those from strains with a functional operon, failed to activate the LEE1 operon and bfpA transcriptional fusions or to complement a per mutant in reference strain E2348/69. Furthermore, O119, O128, and canine strains that carry inactive per operons were deficient in virulence protein expression. The context in which the perABC operon occurs on the EAF plasmid varies. The sequence upstream of the per promoter region in EPEC reference strains E2348/69 and B171-8 was present in strains belonging to most serogroups. In a subset of O119:H2, O128:H2, and O142:H6 strains and in the canine isolate, this sequence was replaced by an IS1294-homologous sequence.
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Project description:The type III protein secretion system is an important pathogenicity factor of enteropathogenic and enterohaemorrhagic Escherichia coli pathotypes. The genes encoding this apparatus are located on a pathogenicity island (the locus of enterocyte effacement) and are transcriptionally activated by the master regulator Ler. In each pathotype Ler is also known to regulate genes located elsewhere on the chromosome, but the full extent of the Ler regulon is unclear, especially for enteropathogenic E. coli. The Ler regulon was defined for two strains of E. coli: E2348/69 (enteropathogenic) and EDL933 (enterohaemorrhagic) in mid and late log phases of growth by DNA microarray analysis of the transcriptomes of wild-type and ler mutant versions of each strain. In both strains the Ler regulon is focused on the locus of enterocyte effacement - all major transcriptional units of which are activated by Ler, with the sole exception of the LEE1 operon during mid-log phase growth in E2348/69. However, the Ler regulon does extend more widely and also includes unlinked pathogenicity genes: in E2348/69 more than 50 genes outside of this locus were regulated, including a number of known or potential pathogenicity determinants; in EDL933 only 4 extra-LEE genes, again including known pathogenicity factors, were activated. In E2348/69, where the Ler regulon is clearly growth phase dependent, a number of genes including the plasmid-encoded regulator operon perABC, were found to be negatively regulated by Ler. Negative regulation by Ler of PerC, itself a positive regulator of the ler promoter, suggests a negative feedback loop involving these proteins.
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Project description:Despite the characterization of many aetiologic genetic changes. The specific causative factors in the development of sporadic colorectal cancer remain unclear. This study was performed to detect the possible role of Enteropathogenic Escherichia coli (EPEC) in developing colorectal carcinoma.
| 2184564 | ecrin-mdr-crc