EPIDEMIOLOGIC-STUDY OF AN ACINETOBACTER-BAUMANNII OUTBREAK BY USING POLYMERASE CHAIN-REACTION FINGERPRINTING

A polymerase chain reaction (PCR) technique was applied to the fingerp rinting of different strains of Acinetobacter baumannii from a cluster of patients infected or colonized with the incriminated pathogen. The DNA was extracted by boiling and was subjected to PCR amplification b y using the core sequence of the M13 phage as a single primer. The amp lified products were separated by agarose gel electrophoresis and were detected by staining with ethidium bromide. In 1990, 49 multiresistan t A. baumannii strains were isolated from 13 patients from the same in tensive care unit of the Charite Hospital; 45 of these outbreak isolat es obtained from 12 patients showed the same PCR patterns, indicating an epidemiological relatedness of these strains. Four strains isolated from the same patient belonged to another genetic group, as revealed by a distinct amplification pattern. Another single subtype of A. baum annii was identified as the causative agent in patients during a secon d outbreak at a different intensive care unit in the same hospital. Se venteen isolates recovered from 10 immunocompromised patients had the same amplification patterns, which were distinct from all other PCR pr ofiles. Five strains were obtained from two other hospitals; three iso lates from the hospital of Magdeburg, Germany, had identical PCR patte rns which, however, could be clearly distinguished from the patterns o f all other strains. The remaining two isolates displayed individual p atterns of amplified fragments. PCR fingerprinting may provide a usefu l and particularly rapid identification technique for epidemiological investigations of nosocomial infections.