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

Abstract

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, stχ1, stχ2) and adherence factors (efa1, lpfAO157, saa) genes. Serogroups O157 (64.4%) and O26 (28.8%) were the most frequent among human strains and the majority (60.6%) of food strains were serologically nontypable. The adhesin genes efa1 (90%) and lpfAO157 (73.3%) were the most common in humans strains and saa (45.5%) 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. © 2006 Cambridge University Press.