Abstract
The source and routes of diarrheagenic Escherichia coli (DEC) remain poorly clarified. To investigate the involvement of domestic animals in the dissemination of DEC, the prevalence of DEC among foods and fecal specimens of cattle, pigs, chickens, healthy carriers, and patients in Osaka and Hyogo, Japan, was investigated using a multiplex real-time PCR assay. The most prevalent virulence genes were astA and eae, with prevalences of 46.8% and 27.4%, respectively. stx1 (26.6%) and stx2 (45.9%) were prevalent in cattle feces, and est (8.5%) and elt (7.6%) were prevalent in pig feces. The afaB gene was the second-most prevalent gene in patients and healthy carriers, with detection rates of 5.1% and 8.1%, respectively. In contrast, afaB was not detected in animal feces and foods, with the exception of three porcine fecal samples. The aggR gene was more prevalent in humans than in foods or animal feces. Not only Shiga toxin-producing E. coli but atypical enteropathogenic E. coli carried by cattle may be a source of diarrheal diseases in humans. Pigs may be the source of human enterotoxigenic E. coli infections, whereas humans are expected to be the reservoir of diffusely adhering E. coli, enteroaggregative E. coli, and enteroinvasive E. coli.
