A widespread community outbreak of E coli O157 infection in Scotland

Between the end of March and the end of May 1994, 22 cases of laboratory-confirmed infection by E coli O157, phage type 4, verotoxin type 1 & 2, were reported to the Scottish Centre for Infection and Environmental Health. Although cases were distributed throughout six health board areas, pulsed field gel electrophoresis indicated that the causative organisms were clonal or very closely related. The eight earliest cases had a connection with a chain of butchers' shops although no organisms were isolated from food or surfaces. A case-control study of 9 cases and 27 controls showed a statistically significant association between consumption of burgers and illness, leading to a statement from the Chief Medical Officer emphasising the importance of thorough cooking of burgers and other meat. This outbreak highlights the importance of a unified approach to epidemiological investigation when several administrative areas are involved.