CLINICAL AND EPIDEMIOLOGIC FEATURES OF AN OUTBREAK OF ACINETOBACTER INFECTION IN AN INTENSIVE THERAPY UNIT

Sporadic examples of infection with multi-resistant Acinetobacter spp. have occurred in Nottingham hospitals since at least 1977, punctuated by more prolonged outbreaks involving larger numbers of patients, par ticularly those confined to the intensive therapy unit (ITU) with seve re underlying disease. In the most recent outbreak, 11 patients were i nfected with multi-resistant Acinetobacter strains and 26 patients wer e colonised. Four of the infected patients died directly or indirectly from infection with multi-resistant Acinetobacter spp., either while in the ITU or after discharge to a general ward. The mean interval fro m admission to the first isolation of a multi-resistant Acinetobacter strain was 6.7 and 12.1 days in the infected and colonised groups, res pectively. Multi-resistant Acinetobacter strains were isolated most fr equently from the respiratory tract, and eight patients had probable o r suspected pneumonia caused by a multi-resistant Acinetobacter sp. Al l infected patients were treated with imipenem, with or without an ami noglycoside, except one patient who died before a diagnosis of acineto bacter infection was confirmed. Multi-resistant Acinetobacter spp. wer e isolated from various environmental sites in the ITU, and patient an d environmental isolates were found to be related closely by biotyping , antibiograms, pulsed-field gel electrophoresis of chromosomal finger prints and ribotyping. The outbreak was controlled ultimately by trans fer of infected or colonised patients to an isolation cubicle, cohort nursing, emphasis on the importance of hand washing before and after p atient contact and when handling case notes, and the use of disposable aprons and gowns during patient contact. These measures were combined with closure of the ITU for decontamination purposes on two separate occasions. Continued surveillance of ITU patients and occasional envir onmental sampling has proved to be important in preventing and control ling subsequent outbreaks of infection by this increasingly important nosocomial pathogen.