Evaluation of a ribosomal RNA gene probe for the identification of species and subspecies within the genus Staphylococcus.

To evaluate a 16S rRNA gene probe for the identification of staphylococcal species and subspecies, we have augmented previous studies involving 12 staphylococcal species by analysing the remaining 16 species currently classified in the genus Staphylococcus. HindIII- and EcoRI-restricted DNA of isolates from validly described species of Staphylococcus was probed with radiolabelled plasmid pBA2 containing 16S rDNA from Bacillus subtilis. The Dice coefficient was used to assess similarity between the 74 HindIII- and the 81 EcoRI-hybridization patterns obtained from a total of 271 isolates belonging to 31 staphylococcal taxa (28 species, of which three include two subspecies). The use of HindIII yielded a better discrimination of the staphylococci than the use of EcoRI. All of the isolates belonging to the same species or subspecies, except S. hyicus isolates, were recovered as homogeneous clusters using their HindIII hybridization patterns. The phenotypically close taxa were clearly distinguished. Thus, the method presented in this study constitutes a powerful tool for the identification of taxa within the genus Staphylococcus.