Distribution of putative adhesins in Shiga toxin-producing Escherichia coli (STEC) strains isolated from different sources in Chile

The distribution of three putative adhesin genes in 123 Shiga toxin-producing (STEC) strains was determined by PCR. The STEC strains were isolated from human patients (n = 90) and food (n = 33) and were characterized by serogroup, virulence markers (eae, stx(1),, stx(2),) and adherence factors (efa1, lpfAO(157), saa) genes. Serogroups O157 (64 center dot 4%) and 026 (28 center dot 8 %) were the most frequent among human strains and the majority (60 center dot 6 %) of food strains were serologically nontypable. The adhesin genes efa 1 (90 %) and lpfA(O157) (73 center dot 3 %) were the most common in humans strains and saa (45 center dot 5 %) in food strains. The presence of these genes in addition to eae in STEC from different sources may suggest a relevant role in their pathogenesis.