Prevalence and characteristics of eae-positive Escherichia coli from healthy cattle in Japan.

The prevalence of eae-positive Escherichia coli (eaeEC) in Japan was examined using rectal stool samples taken from 35 calves less than 1 month old, 107 calves more than 1 to 3 months old, 88 heifers more than 3 to 6 months old, 214 heifers over 6 months old, and cows from 95 farms. Screening with eae PCR revealed the prevalence to be, with increasing age, 31.4, 8.4, 26.1, and 14.5%, respectively. Of 51 selected eaeEC strains, more than 40% were serotyped as O26, O103, O111, O145, or O157, which are frequently detected as enterohemorrhagic E. coli types. Four strains were identified as recently reported intimin types eta, iota, and kappa.