Verocytotoxin-producing Escherichia coli O26 infection in calves.

摘要

The findings from a recent farm investigation in which verocytotoxin-producing Escherichia coli O26 (VTEC) was recovered from clinically normal cattle following an initial isolation in faeces from a scouring calf were reported. The isolate was submitted from a 2-month-old calf in a 33-cow beef suckler and calf-rearing enterprise. Several of the suckler calves developed diarrhoea, but only one was sampled. The sample was submitted to the Veterinary Laboratories Agency (VLA) for limited diagnostic testing. This animal subsequently died. Examination of the faecal sample did not show any potential pathogens apart from E. coli. The isolate was examined under the enhanced E. coli surveillance programme and identified as E. coli O26 with genes for verocytotoxin 1 and intimin, which were associated with intestinal attachment and effacement. Faecal samples were taken from the previously affected group of suckler calves and screened for E. coli O26. Eight of the ten samples from the calves and five of the six samples from the cows were positive. From May 2005 to May 2006, a total of 294 cattle isolates were included in the VLA enhanced E. coli surveillance survey. Of these, 14 were VTEC, and serogroup O26 was the most prevalent. VTEC O26 appeared to be a frequent contributor to the gut flora of cattle and could be isolated from both scouring and clinically normal animals..