Multidrug resistance among methicillin-resistant Staphylococcus aureus in Greece

A total of 472 strains of Staphylococcus aureus isolated in a university hospital in Thessaloniki, Greece during 1993-1994 were studied; 202 (42.8%) of them were characterized as methicillin-resistant (MRSA) and were mainly recovered from respiratory materials. The minimal inhibitory concentrations (MICs) of methicillin-susceptible (MSSA) and methicillin-resistant strains to 10 alternative antibiotics were also compared. All MRSA isolates were resistant to penicillin and most of them, in contrast to MSSA, exhibited resistance to gentamicin, tobramycin, tetracycline, erythromycin and ciprofloxacin with resistance rates ranging from 89.6% to 59.4%. Also, considerable proportions of MRSA were found resistant to co-trimoxazole (47.0%) and rifampicin (27.7%). All isolates were sensitive to vancomycin while susceptibility to chloramphenicol was of equal incidence among the examined populations. Overall, MRSA vs. MSSA exhibited a significantly (chi 2; P<10-8) higher incidence of resistance to 8 out of the 10 antibiotics examined.