Cattle as a possible source of verocytotoxin-producingEscherichia coliO157 infections in man

Abstract

SummaryIn May-June 1992 cases of infection with verocytotoxin-producing (VT+)Escherichia coliO157 in South Yorkshire could have been associated with prior consumption of beef from a local abattoir. During investigation of the abattoir, bovine rectal swabs and samples of meat and surface swabs from beef carcasses were examined forE. coliO157, isolates of which were tested for toxigenicity, plasmid content and phage type.E. coliO157 was isolated from 84 (4%) of 2103 bovine rectal swabs; of these 84, 78 (93%) were VT+, the most common phage types being 2 and 8, the types implicated in the cluster of human cases. Positive cattle were from diverse sources within England.E. coliO157 was isolated from 7 (30%) of 23 carcasses of rectal swab-positive cattle and from 2 (8%) of 25 carcasses of rectal swab-negative cattle. The study has shown that cattle may be a reservoir of VT+E. coliO157, and that contamination of carcasses during slaughter and processing may be how beef and beef products become contaminated and thereby transmit the organism to man.