Long-term survival of Shiga toxin-producing Escherichia coli O26, O113, and O157 in bovine feces

Cattle are an import:mt reservoir of Shiga toxin-producing Escherichia coli (STEC) O26, O111, and O157. The fate of these pathogens in bovine feces at 5, 15, and 25 degrees C was examined. The feces of a cow naturally infecte d with STEC O26:H11 and two STEC-free cows were studied. STEC O26, O111, an d O157 were inoculated into bovine feces at 10(1), 10(3), and 10(5) CFU/g. All three pathogens survived at 5 and 25 degrees C for 1 to 4 weeks and at 15 degrees C for 1 to 8 weeks when inoculated at the low concentration. On samples inoculated with the middle and high concentrations, O26, O111, and O157 survived at 25 degrees C for 3 to 12 weeks, at 15 degrees C for 1 to 1 8 weeks, and at 5 degrees C for 2 to 14 weeks, respectively. Therefore, the se pathogens can survive in feces for a long time, especially at 15 degrees C. The surprising long-term survival of STEC O26, O111, and O157 in bovine feces shows that such feces are a potential vehicle for transmitting not o nly O157 but also O26 and O111 to cattle, food, and the environment. Approp riate handling of bovine feces is emphasized.