Quantitative differences in antibiotic resistance between methicillin-resistant and methicillin-susceptible Staphylococcus aureus strains isolated in Hungary, Austria and Macedonia.

The aim of this study was to compare the quantitative susceptibility of methicillin-resistant and -susceptible Staphylococcus aureus (MRSA and MSSA) strains from three European countries to nine antistaphylococcal agents. The antibiotic susceptibility of 274 MRSA and 284 MSSA strains from Hungary, Austria and macedonia was tested by the broth microdilution method. The clonal relationship of strains was determined by pulsed-field gel electrophoresis. Intermediate susceptibility to vancomycin appeared in Macedonian MRSA strains. Macedonian MRSA strains had high-level amikacin and gentamicin resistance. MSSA strains generally were susceptible to all drugs at minimum inhibitory concentrations (MIC(50)) except for gentamicin resistance in Macedonian strains. In Hungary and Austria a common antibiotic resistance phenotype of MRSA predominated, while in macedonia three other phenotypes were also prevalent. Geographical differences in the resistance of S. aureus are still high. Since resistance levels of MRSA and MSSA strains differ extensively, they should be considered separately for antibiotic resistance analysis.