The epidemiology of a large single-strain outbreak of vancomycin-resistant Enterococcus faecium vanB in an Australian teaching hospital

Abstract

A single-strain outbreak of vancomycin-resistant Enterococcus faecium (VREF) vanB occurred in Royal Perth Hospital (RPH) from 23 July to 28 December 2001. One hundred and seventy two patients were colonised, four with infections, but no deaths were attributable to VREF. One hundred and eighteen patient carriers were detected by screening in hospital. Twenty three wards or units in the hospital and one outpatient unit (Satellite Dialysis) were involved. Fifty four patient carriers were detected by screening after discharge or on representation to RPH or other hospitals. Pulsed-field gel electrophoresis and plasmid analysis of the isolates demonstrated a single-strain outbreak. Factors which contributed to the spread of VREF in RPH included insufficient surveillance prior to the outbreak and not screening patients on transfer out of ICU to other wards, inadequate facilities (lack of sufficient single rooms, isolation facilities and washer-sanitisers for reusable equipment), poor compliance with hand hygiene, inadequate cleaning of wards (environmental contamination was demonstrated on many of the wards where transmission to patients was detected), inadequate cleaning of commodes between patient use, shortage of nurses, patient management practices (accommodation of patients with diarrhoea, colostomy or faecal incontinence on open wards with shared room and toilet facilities, multiple transfers of patients within and between wards, sharing of equipment between adjacent wards on the same floor), length of time for the laboratory to isolate VREF from rectal screening swabs, and the use of third generation cephalosporins and fluoroquinones. The outbreak was terminated by a wide range of infection control and administrative measures.