Prevalence of Escherichia coli O157 strains in cattle, pigs and humans in North West province, South Africa

WE HAVE DETERMINED THE PREVALENCE of Escherichia coli O157 steains in cattle, pigs and humans. Eight hundred faecal samples were analysed, but only those isolates that satisfied all primary (oxidase and the triple sugar iron) and secondary identification criteria (API 20E) for E. coli are reported. A total of 294 E. coli isolates were further analysed for E. coli O157 characteristics by the slide agglutination test with E. coli O157-specific monovalent antiserum. Seventy-six E. coli O157 isolates were positively identified. In this group of isolates, the prevalence was higher in pigs (44-50%) than in cattle (5.4-20%) and humans (7.5%). Within the pig isolates, the prevalence was higher in the commercial (51%) than in the communal (44%) pigs. Similarly, the prevalence was higher in faeces from commercial (14-20%) than communal cattle (5.4%). This study highlights the need for correct hygiene, especially with commercial farming of cattle and pigs, and the processing of their products. Through this precaution, prevalence of E. coli O157 in farm animals can be minimized, preventing spread from animals to humans.