New method for typing Staphylococcus aureus strains: multiple-locus variable-number tandem repeat analysis of polymorphism and genetic relationships of clinical isolates.

The PCR-based methodology applied to multiple-locus variable numbers of tandem repeat (VNTR) analysis was recently shown to be a useful technique for the molecular typing of clinical isolates of several bacterial species. We have adopted this method for the molecular typing of methicillin-resistant Staphylococcus aureus. Five staphylococcal VNTR loci (sdr, clfA, clfB, ssp, and spa) were subjected to analysis, and it was shown that the method allows typing of S. aureus strains with the discriminatory power and reproducibility of pulsed-field gel electrophoresis while at the same time being rapid and applicable to analysis of large numbers of isolates.