Characterization of methicillin resistant Staphylococcus aureus (MRSA) isolated at the Policlinico Hospital of Bari (Italy).

Methicillin resistant Staphylococcus aureus (MRSA) is an emerging problem. We studied 71 MRSA strains for the presence of mecA gene by PCR, for the enterotoxins production and susceptibility to antimicrobials. In addition, the suitability of Random Amplified Polymorphic DNA analysis (RAPD) and Hypervariable Region (HVR)--PCR as molecular tools for typing MRSA was also tested. All the 71 strains previously found MRSA with conventional methods, presented the gene mec A. By molecular typing five distinct amplicons were found. MRSA with two DRUS were the most common type. RAPD analysis clustered MRSA in 8 groups, three of which were the most common. 26.8% of MRSA produce enterotoxins with a prevalence of type A. MRSA exhibited resistance to all quinolones tested and to gentamycin. Our data suggest that a typing method based on RAPD combined with HVR-PCR may be useful to compare MRSA isolated in a hospital environment, whereas PFGE may be used for further analysis.