CHARACTERIZATION OF METHICILLIN-RESISTANT STAPHYLOCOCCUS-AUREUS ISOLATES FROM PORTUGUESE HOSPITALS BY MULTIPLE GENOTYPING METHODS

One hundred and eighty-three methicillin-resistant Staphylococcus aure us (MRSA) isolates from eight different Portuguese hospitals were gene tically typed by random amplification of polymorphic DNA (RAPD) employ ing different oligonucleotide primers, Fourteen different RAPD genotyp es were identified, A subset of the same strains was also characterize d by pulsed-field gel electrophoresis (PFGE) and/or hybridization usin g mecA and Tn554 probes, In the majority of cases, the different genot yping methods have identified the same MRSA clones, However, PFGE comb ined with the DNA probes was clearly the method providing higher resol ution, Most strains that have already been identified by PFGE and DNA probes as members of the widely spread Iberian clone of MRSA generated a common RAPD genotype, The most prevalent Iberian clone was not dete cted in a collection of MRSA from Poland that was also examined by RAP D, On the other hand, MRSA strains second most frequent in prevalence in the Portuguese and Polish collection appear to be identical by RAPD , indicating extensive geographic spread of this particular clone, No correlation was apparent between epidemic behavior and the number of p rotein A gene repeats in this particular collection of MRSA strains.