Methicillin-resistant staphylococci.

Staphylococcus aureus and coagulase-negative staphylococci are among the most frequent causes of nosocomial infections, in addition to their role in community-acquired infections. The incidence of resistance to penicillinase-resistant penicillins (methicillin, oxacillin, nafcillin, and the cloxacillins) is steadily increasing. These methicillin-resistant staphylococci are usually resistant to several classes of antimicrobial agents.