ABSTRACT
The 16S-23S intergenic spacer regions of four Acinetobacter genomic species belonging to the A. calcoaceticus-A. baumannii (Acb) complex, i.e. genomic species 1 (A. calcoaceticus), genomic species 2 (A. baumannii), genomic species 3 and Tjernberg and Ursing (TU) genomic species 13, have been cloned and sequenced. Sequence analysis led to the discovery of a single copy of IIe and Ala tRNA genes within each spacer. Sequence comparison allowed the identification of a 192-base-pair long highly 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 specific to, respectively, genomic species 2 and 3, could be identified. Oligonucleotides corresponding to these sequences were constructed and tested for the ability to hybridize with chromosomal DNA extracted from Acinetobacter belonging to different genomic species and with chromosomal DNA of other bacterial genera. One of these oligonucleotides was 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.
Subject(s)
Acinetobacter/genetics , DNA, Bacterial/genetics , DNA, Ribosomal/genetics , Oligonucleotide Probes , Acinetobacter/classification , Cloning, Molecular , Molecular Sequence Data , Nucleic Acid Hybridization , RNA, Ribosomal, 16S/genetics , RNA, Ribosomal, 23S/genetics , RNA, Transfer, Ala/genetics , RNA, Transfer, Ile/genetics , Sensitivity and Specificity , Sequence Alignment , Sequence Analysis, DNA , Species SpecificityABSTRACT
The 16S-23S intergenic spacer region in 218 strains of Salmonella isolated from four Italian hospitals during the period from 1977 to 1994 was analyzed by PCR ribotyping. This molecular typing technique allowed for the identification of seven different and specific electrophoretic profiles for the seven serovars S: enteritidis, S. london, S. anatum, S. panama, S. heidelberg, S. agona, and S. goldcoast. Otherwise, the spacer region appears to be polymorphic in S. typhimurium S. infantis, and S. derby since we could identify eight, six, and four different ribotypes, respectively.