Molecular identification of Escherichia coli potentially causing food toxi-infections in cheeses coalho and ricotta

Abstract

Cheeses are considered to present a high risk of spreading pathogenic microorganisms, mainly bacteria causing food toxi-infections. The aim of this project is to isolate and identify strains of Escherichia coli potentially causing food toxic-infections in cheeses "coalho" and ricotta traded in the central-east region of São Paulo State and "triângulo Mineiro" region of Minas Gerais State. It will be evaluated the pathotypes EPEC (enteropathogenic), EIEC (enteroinvasive), ETEC (enterotoxigenic), STEC (vetrotoxigenic) and EAEC (enteroaggregative). Thirty samples of each cheese will be acquired, in supermarkets, during a six-month period, making five samples of each cheese per month and adding up 60 samples analyzed. Isolated colonies will be submitted to DNA extraction. Following, two PCR multiplex reactions will be performed, one to amplify genes responsible for the production of thermolabile toxin 1 (LT1), thermolabile toxin 2 (LT 2), thermostable toxin (ST1), verotoxin (VT1 e VT2), and the gene that codifies intimin adhesin (eae); and other to detect ipaH gene from invasion plasmid (pInv) and aaTa gene from pAA plasmid of aggregative adherence (AA), present in EIEC and EAEC, respectively. (AU)