Enteropathogenic Escherichia coli (EPEC ) is one of the main groups of diarrheagenic E. coli (DEC) and of the most frequent pathotypes cause of diarrhea. It may be differentiated in typical ( tEPEC ) and atypical ( aEPEC ) based on the presence of pEAF plasmid, which encodes the bfp gene responsible for the expression of fimbrial bundle forming pilus ( BFP ) in tEPEC strains and the absence in aEPEC strains. The aEPEC , due to the absence of BFP, has an alternative mechanism for adhesion to the host cell , such as the presence of fimbrial and nonfimbrial adhesins . The variability of these mechanisms highlights the importance of its study to unravel its role in the ability of interaction between bacteria and eukaryotic cell. In a study conducted in our laboratory, were surveyed 31 fimbrial genes in a collection of 72 aEPEC isolates. Among the studied genes, some were more prevalent as fimA and fimH encoding type I pilli, and the ecpA gene, encoding ECP ( E. coli common pilus ). Furthermore, variants of lpf gene, such as lpfA1 -2, lpfA2 -1, lpfAO113, lpfA1-1, lpfA1- 3, were found in different prevalences amoung the analyzed samples. Finally, other genes were found in lower prevalence, as pilS and pilV encoding a type IV pilli described in an enteroaggregative E. coli isolate. Data obtained by our group have shown that the presence of the gene encoding this adhesin does not indicates the expression of it, due to the identification of pils and pilV genes in three bacterial isolates with different patterns of adherence to HEp-2 cells, by PCR, showed different transcription profile, with only two strains able to transcribe them. In the BA1244 isolate these genes are not transcribed, although it shows the Localized Adherence-Like (LAL) pattern and has a pilli genetic profile quite complex. These results lead us to the goals of this project, which is to characterize the localized adherence-like pattern in three isolates that present different pilli genetic profiles, analyzing which genes are being transcribed and the expression of their fimbrial adhesins.
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