A COMPARATIVE-STUDY OF RIBOTYPING AND ARBITRARILY PRIMED POLYMERASE CHAIN-REACTION FOR INVESTIGATION OF HOSPITAL OUTBREAKS OF ACINETOBACTER-BAUMANNII INFECTION

Arbitrarily primed polymerase chain reaction (AP-PCR) and ribotyping w ere compared in an investigation of an outbreak of Acinetobacter bauma nnii infections. Twenty-five clinical isolates shown previously by oth er criteria to belong to two different groups, and nine randomly selec ted A. baumannii clinical isolates from other hospitals were investiga ted. Among the strains analysed, nine different EcoRI rRNA gene restri ction pattern fingerprints were observed. While similarity was detecte d between strains of the same group, these fingerprints differed clear ly between the two A. baumannii groups defined in the outbreak. Two of the nine strains selected randomly had the same ribotype as those str ains involved in the outbreak, whereas the remaining seven strains eac h had a different ribotype. When the strains were tested by AP-PCR wit h 0.25, 0.5 or 1 mu M of M13 forward primer, 10 different profiles wer e obtained. However, 11 profiles were observed if two different primer concentrations (0.25 and 1 mu M) were used. It was concluded that rib otyping and AP-PCR exhibited a similar discriminatory power, although AP-PCR had the additional advantages of speed and simplicity.