DNA sequence-based tandem repeat analysis of the clfB gene is less discriminatory than spa typing for methicillin-resistant Staphylococcus aureus

Methicillin-resistant Staphylococcus aureus (MRSA) are a major challenge for hospital hygiene. Typing by DNA sequence analysis of the repeat region of the protein A gene (spa) significantly improved typing of MRSA in the hospital setting. However, microevolution of spa repeats in epidemic clones appears to occur at a fairly slow clock rate. Therefore, DNA sequence-based methods providing additional resolution are desirable in some situations. We evaluated the use of the clfB repeat region proposed recently by others as a possible complementation to spa typing. Using epidemic MRSA isolates from two German university hospitals, we show that the clfB repeat region does not offer any additional discriminatory power.