ACINETOBACTER SPECIES IDENTIFICATION BY USING TRANSFER-RNA SPACER FINGERPRINTING

Identification of Acinetobacter spp. to the DNA group level by phenoty pic techniques is problematic, and there is a need for an alternative identification method for routine use. The present study validated the suitability of a rapid identification technique based on tRNA spacer (tDNA) fingerprinting in comparison with that of a commercially availa ble assay involving carbon source utilization tests (Biolog MicroStati on System) for identifying the 21 DNA-DNA hybridization groups belongi ng to the genus. For this purpose, 128 strains identified previously b y DNA-DNA hybridization were analyzed by both techniques. tDNA fingerp rinting was highly reproducible and classified all strains into 17 gro ups. Six DNA groups belonging to the A. calcoaceticus-A. baumannii com plex were grouped into two distinct clusters, indicating the high degr ee of genetic similarity within this complex. Strains of the more rece ntly described DNA groups BJ13 to BJ16 were ambiguously grouped and di splayed three pattern types. The software used with the commercial car bon source utilization method grouped the 128 strains into 12 clusters , explaining the less discriminatory power of this system. We conclude that tDNA fingerprinting offers a quick and reliable method for the r outine differentiation of most Acinetobacter spp. at the subgenus leve l.