Comparison of two different methods for determination of hVISA rates in methicilline-resistant staphylococcus aureus

Staphylococcus aureus (MRSA) infections, but resistance and heterogeneous resistance to vancomycin have been reported recently. Except vancomycin-resistant S. aures (VRSA) and vancomycin-moderately resistant S. aureus (VISA), one of the important causes of failure in the treatment process of staphylococcal infections is considered to be vancomycin heterogeneous-intermediate resistant S. aureus (hVISA). But detecting hVISA is a labor-intensive and specialized procedure. In our study, it was aimed to determine the hVISA rates in MRSA strains isolated from Sanko University Hospital. In addition, we compared Brain Heart Infusion screening agar developed by Satola and the population analysis profile (PAP-AUC) method, which is accepted as the gold standard. First of all, MIC values of all bacteria were determined by broth microdilution method and all strains were found to be sensitive to vancomycin. Then, Satola method was perfomed and 28 strains (46.66%) were determined as hVISA. The strains detected as hVISA were re-evaluated in the PAP-AUC method. Among 28 MRSA strains, only 12 (20% of all isolates) strains were identified as hVISA. In our study, hVISA rates were investigated for the first time in our region usingSatola's method and PAP-AUC method. The rate of false positivity was found to be high when Satola test and PAP-AUC were compared.