Isolation of Escherichia coli O157 from human and bovine faeces in the Urbino area, Italy

We examined 476 faecal samples from subjects aged from 0 to >60 years, 283 with diarrhoea and 193 with illnesses involving other sites or clinically healthy, and 154 samples of faeces of healthy cattle, in order to define the diffusion of E. coli O157 in the Urbino area. The samples were seeded by both direct streaking onto cefixime tellurite sorbitol Mac Conkey agar (CT-SMAC) and previous enrichment in cefixime tellurite tryptone soya broth for human specimens and in cefixime vancomicin tryptone soya broth for bovine samples. The strains of E. coli O157 were characterized by verocytotoxin and adhesin eae genes detection. We isolated one strain of E. coli O157 (0.2%) from a man 68 year old who had bloody diarrhoea, and one strain (0.64%) from a weaned calf. Both isolates carried the adhesin eae gene, but only the bovine strain was VT2+. The study shows a low diffusion of E. coli O157 in the Urbino area, confirming the epidemiological data on the national territory.