USE OF INTERREPEAT PCR FINGERPRINTING TO INVESTIGATE AN ACINETOBACTER-BAUMANNII OUTBREAK IN AN INTENSIVE-CARE UNIT

An epidemiological investigation of an outbreak of Acinetobacter bauma nnii among patients on 2 closely related intensive care units (ICU) wa s performed by molecular typing with interrepeat polymerase chain reac tion (interrepeat PCR). 31 A. baumannii isolates obtained from 15 ICU patients were characterized. All patients were infected or colonized w ith A. baumannii. After identification of the outbreak, 6 environmenta l isolates were collected from tap-water, sinks and cleaning detergent s. PCR fingerprinting identified 3 genotypes among the outbreak-relate d strains. One predominant genotype was demonstrated in 14/15 patients and this genotype was also found among all environmental isolates. Th e cluster of A, baumannii represented an outbreak of 1 genotype, sugge sting cross-contamination. The finding of the identical genotype among all environmental strains indicated a common environmental source cau sing the outbreak. The outbreak was controlled after reimplementation of an effective disinfection of workplace surfaces. This survey proved interrepeat PCR to be a rapid and reliable method to differentiate A. baumannii strains, thereby allowing epidemiological surveillance of l arge amounts of strains and early interventions to control outbreaks.