CHARACTERIZATION OF OLIGONUCLEOTIDE PROBES FOR THE IDENTIFICATION OF ACINETOBACTER SPP., A-BAUMANNII AND ACINETOBACTER GENOMIC SPECIES-3

The 16S-23S intergenic spacer regions of four Acinetobacter genomic sp ecies belonging to the A. calcoaceticus-A. baumannii (Acb) complex, i. e. genomic species 1 (A. calcoaceticus), genomic species 2 (A. baumann ii), genomic species 3 and Tjernberg and Ursing (TU) genomic species 1 3, have been cloned and sequenced. Sequence analysis led to the discov ery of a single copy of IIe and Ala tRNA genes within each spacer. Seq uence comparison allowed the identification of a 192-base-pair long hi ghly conserved sequence between the 3' end of the 16S rRNA and the 5' end of the tRNA(Ala) genes. Moreover, two short regions, which were sp ecific to, respectively, genomic species 2 and 3, could be identified. Oligonucleotides corresponding to these sequences were constructed an d tested for the ability to hybridize with chromosomal DNA extracted f rom Acinetobacter belonging to different genomic species and with chro mosomal DNA of other bacterial genera. One of these oligonucleotides w as demonstrated to be useful as a sensitive and specific probe for A. baumannii. A less sensitive probe for Acinetobacter genomic species 3 was also developed.