Evaluation of different methods to detect methicillin resistance in small-colony variants of Staphylococcus aureus.

To evaluate different methods for their abilities to detect methicillin resistance in small-colony variants (SCVs) of Staphylococcus aureus, 11 different methicillin-resistant S. aureus (MRSA) clones with the SCV phenotype were used in this study. The slow growth of SCVs often makes testing by disk diffusion or by automated methods invalid. Only detection of the mecA gene by PCR and the MRSA-Screen latex agglutination test using a higher colony number were shown to be reliable methods to rapidly detect methicillin resistance in these variants.