Reliable identification of clinically prevalent species and subspecies of staphylococci by sodium dodecyl sulfate polyacrylamide gel electrophoresis analysis

We identified by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) 10 species and 5 subspecies of Staphylococcus among 139 clinical isolates and compared it with conventional tests. All isolates showed species-specific whole-cell protein profiles, even atypical strains, with up to 60% and at least 73.5% of interspecies and intraspecies similarity, respectively. Except for 5 isolates that presented biochemical profiles of Staphylococcus hominis subsp. hominis, but were identified as S. hominis subsp. novobiosepticus by SDS-PAGE, there was 100% accordance between the methods used. Comparison with the partial 16S-rDNA sequences confirmed by SDS-PAGE showed the high accuracy of this method to identify staphylococci subspecies and species.