Staphylococcus aureus is a major human pathogen causing skin and tissue infections, pneumonia, septicemia, and device-associated infections. The emergence of strains resistant to methicillin (MRSA) and other antibacterial agents has become a major concern, especially in the hospital environment, because of the high mortality of the infections caused by these strains. Single locus DNA-sequencing of the polymorphic VNTR in the 3′ coding region of the Staphylococcus protein A gene (spa) can be used for reliable, accurate and discriminatory typing of MRSA. Repeats are assigned a numerical code and the spa-type is deduced from the order of specific repeats.
SPA typing has been shown to be highly concordant with MLST and some studies suggest that it is suitable for macroepidemiology and evolutionary investigations based on studies of European and international isolates.