Identification of Acinetobacter calcoaceticus - Acinetobacter baumannii Complex by Ribotyping

ABSTRACT

Acinetobacter species encounters frequently with clinical specimens and now accounts for a substantial proportion of endemic nosocomial infections in Korea. Recent trends indicate that the antimicrobial resistant strains of Acinetobacter species are increasing. Sixty-one strains were isolated from specimens of patients suspected of nosocomial infections during 1991 to 1996. At present, phenotypic identification of Acinetobacter using biochemical test may not be reliable and resulted in the difficulty to clarify the source of infections and epidemiological study of hospital-acquired infections. Aware of the importance of rational taxonomic proposal for these isolates, correct species identification of these organisms by molecular typing method was carried out. A total of fifty-four strains of A. calcoaceticus-A. baumannii complex species which were identified to genospecies 2 and 13 by biochemical characteristics was subjected to identify by ribotyping using restriction endonuclease EcoRI, ClaI, and SalI. Of fifty-four strains, twenty-five strains were identified as A. baumannii (genospecies 2) and twenty-one strains as genospecies 13, and six strains changed to genospecies 3, and the rest two strains were confirmed as A. haemolyticus (genospecies 4). This result suggests that the ribotyping may be of value for identification of genospecies and epidemiological information of Acinetobacter strains.