Methicillin-resistant Staphylococcus aureus as a cause of community-acquired pneumonia--a critical review

Methicillin-resistant Staphylococcus aureus (MRSA) has been recognized as a nosocomial pathogen in Europe and North America for 3 decades. More recently it has emerged as a problem in long-term care facilities. It is less frequently considered a pathogen in nonfacility, community-acquired infections, where it is most often seen in intravenous drug users. There are no studies in the literature specifically describing the clinical features of MRSA pneumonia. Presumably its presentation and outcome are similar to that of pneumonia caused by susceptible strains. Staphylococcus aureus pneumonia is more often nosocomial- or nursing home-acquired, has a variable association with influenza, has clinical and laboratory features similar to other types of community-acquired pneumonia and carries a relatively high mortality of 20% to 84%. MRSA should be considered resistant to all classes of beta-lactam (beta) antibiotics. In addition, these isolates are frequently resistant to a number of other antibiotics, with vancomycin and only antibiotic to have consistently shown activity against MRSA. Therefore, vancomycin remains the treatment of choice for infections caused by MRSA, although treatment failures have been reported. The use of alternative antibiotics should be based on results of susceptibility testing of the strain isolated from the patient.