Enteropathogenicity markers in Escherichia coli strains isolated from softwhite cheese and poultry in Rio de Janeiro, Brazil

Diarrhoeagenic Escherichia coli is the main cause of infantile diarrhoea in Brazil Unseasoned soft white cheese and poultry are cheap foods widely con sumed by adults and children in Brazilian cities. To assess the risk involv ed in consumption of these foods, virulence markers were investigated in 57 5 E. coli colonies isolated from 44 soft white cheese and 39 chicken carcas s samples. Escherichia coli colonies were tested with enteropathogenic E. c oli (EPEC) enteroinvasive E. coli (EIEC) and O157 antisera and tested for a dherence to HEp-2 cells, FAS test, enterohemolysin production, Dean assay f or STa and DNA hybridization with eae, EAF, stx and LT-1 probes. Shiga toxi n (Stx) production by probe-positive strains was tested on Vero cells. Esch erichia coli strains of EPEC serogroups O727 and O128 were found in 17;3% o f cheese samples and O114, O119 and O158 were found in 10.2% of chicken sam ples examined. None of these produced localized adherence on HEp-2 cells or hybridized with eae and EAF probes. EIEC, enterotoxigenic E, coli (ETEC) a nd enterohemolysin-producing E. coli was not detected Two non-O157 E. coli strains (serotypes O?H28 and R:H?) isolated from chicken carcasses hybridiz ed with stx2 probe and one of them also hybridized with eae probe. However, none of these strains were positive for enterohaemolysin, FAS, adhered to HEp-2 cells or produced cytotoxic effects on Vero cells. (C) 2000 Academic Press.