Prevalence of Shiga toxin- and enterotoxin-producing Escherichia coli in patients and animals in Guizhou, China

Abstract:

[Objective]: To assess the public health risk, we studied the prevalence of enterotoxigenic Escherichia coli (ETEC) and Shiga toxin-producing E. coli (STEC) among pig, cattle and human in Guizhou Province. [Methods]: E. coli isolates from fecal samples were investigated for their virulence markers by polymerase chain reaction (PCR) assays. [Results]: Of 333 E. coli isolates, ETEC was predominant and detected in 73 of 112 isolates from patients, 82 of 106 isolates from pigs, and 18 of 115 isolates from cattle. The distribution of genes st, lt, and st/lt was equivalent in ETEC isolates. The detection rate of STEC from pig isolates was higher than that from patient and cattle isolates, most of which carried genes for st or lt or both. Furthermore, we analyzed the presence of the fedA gene encoding the major subunit of F18 fimbriae in E. coli isolates. Although most isolates were negative in the PCR, the presence of F18 fimbriae in the E. coli isolates was always associated with enterotoxin genes. In 25 stx-positive STEC isolates, however, only 4 STEC from pigs with diarrhea detected fedA. [Conclusion]: These results indicate that ETEC, coexisting with F18 fimbriae, is common in patients, cattle, and pigs, while STEC is dominant in pigs in Guizhou Province, China.