SENSITIVITY TO ANTIBIOTICS IN STRAINS OF STAPHYLOCOCCUS AUREUS ISOLATED FROM COWS MILK

Strains of Staphylococcus aureus (S. aureus ) were isolated from individual milk samples of 500 lacting cows from different areas in Slovakia (PH 1 – Kosice region, 300 samples; PH 2 – Žilina region, 200 samples). The statistical significance between both dairy farms included in the experiment in the presence of genus Staphylococcus isolated on Baird-Parker agar from milk samples was p < 0,0001 (***) . Totally, 122 milk samples were positive for the presence of Staphylococcus aureus (83 Kosice regions, 52 Žilina regions). All 122 isolates of S. aureus were sensitive for the methicilin as detected by interpretative criteria developed by NCCLS (2002). For 122 S. aureus isolates, we compared antibiotic susceptibility results determined by the standardized agar diffusion assay with the PCR assay for the detection of antibiotic resistance mec A gene. For all isolates, we found a correlation between the results of the PCR and those of classical resistance testing. The obtained results were confirmed by PCR analysis, according to which, any of our tested isolate of S. aureus from all 122 individual milk samples from both experimental dairy farms were not positive for the presence of mec A gene coding the methicilin resistance.