A severe outbreak of E. coli O157 in two psychogeriatric wards.

In October 1990 there was a severe outbreak of Escherichia coli O157 in two psychogeriatric wards of a large psychiatric hospital in Lanarkshire. There were 11 cases (eight patients and three staff), of whom four died (all patients). Two cases, one staff and one patient (the likely index case) were identified serologically after the outbreak was over. E. coli O157 was not cultured from any food, water or milk samples, and the evidence suggests that the index case had eaten food brought into the hospital. The results also suggest that the incubation period of the organism may be longer than is currently recognized, particularly for person-to-person spread. A Fatal Accident Inquiry was held into the deaths, and the Sheriff's Determination is discussed together with the implications of the results for infection control procedures.