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Molecular analysis of virulence genes of atypical Enteropathogenic Escherichia coli (aEPEC) belonging to classical serogroups

Grant number: 11/16112-7
Support type:Scholarships in Brazil - Master
Effective date (Start): May 01, 2012
Effective date (End): August 31, 2013
Field of knowledge:Biological Sciences - Microbiology
Principal Investigator:Isabel Cristina Affonso Scaletsky
Grantee:Nathalia Bibiana Teixeira
Home Institution: Escola Paulista de Medicina (EPM). Universidade Federal de São Paulo (UNIFESP). Campus São Paulo. São Paulo , SP, Brazil

Abstract

SummaryEnteropathogenic Escherichia coli (EPEC) is subdivided into typical and atypical, and have the typical eae gene and EAF plasmid, and have atypical eae gene, but do not carry the EAF plasmid. Atypical EPEC has been found to cause diarrhea in several countries, including Brazil, surpassing the typical EPEC. Samples of atypical EPEC may or may not belong to the classical EPEC serogroups. Just as typical, the atypical carrying the pathogenicity island LEE (locus of enterocytes effacement) and high molecular weight plasmids, which have not been studied. Samples of atypical EPEC can adhere or not to HEp-2. The members expressed predominantly the pattern of localized adherence-like (ALL), in which one observes the formation of microcolonies and occurs late in relation to the pattern typical of AL. The default is mediated by AL BFP fimbriae encoded by the bfp operon present in the EAF plasmid, which contains the transcriptional activator perABC (-plasmid-encoded regulator). In a recent project of phenotypic and genotypic characterization of samples of atypical EPEC isolated from children with diarrhea were detected samples belonging to classical serogroups O26, O55, O111, O119, O127, and O142 showed that the standard AL. Plasmid profile analysis of two representative samples of each serogroup showed the presence of high molecular weight plasmids. This project aims to study the molecular aspects of the LA phenotype of these samples in order to explain it. More specifically, to investigate the relationship of high molecular weight plasmids with the EAF plasmid, analyzing the genes of the LEE region, and bfp perABC and characterize the types of allelic genes eae and perA.