Virulence markers of Escherichia coli strains isolated from traditional cheeses made from unpasteurised sheep milk in Slovakia

Numerous virulence factors including adhesins, host cell surface-modifying factors, invasins, toxins, and secretion systems are involved in Escherichia coli pathogenicity mechanisms. Strains of the same pathotype are genetically similar and carry the same virulence determinants which are ideal targets for the determination of the pathogenic potential of any given E. coli isolate. We examined 95 strains of E. coli isolated from two kinds of traditional Slovak cheeses made from raw sheep milk in course of one year. We tested those strains with the goal to determine some of 11 selected genes of virulence factors which at least partially represent all frequent pathotypes of E. coli. Markers of VTEC (VT1, VT2, VT2e), ETEC (ST I, ST II, LT I), EPEC (EaeA), EIEC (Einv), EAEC (Eagg), and UPEC (CNF1, CNF2) were examined using PCR assays. The result of our testing was the determination of nine potentially pathogenic strains from 95 isolates (9.72%). We did not prove VT1 and VT2 factors as well as Einv and Eagg in any strains. We detected ST I in two strains, ST II and LT I in one strain, and VT2e in one strain. In this study most frequent virulence markers were CNF 1 (three strains) and EaeA (three strains).