Methicillin-Resistant Staphylococcus aureus Decolonization “Yes, We Can,” But Will It Help?

Approximately 100,000 invasive methicillin-resistant Staphylococcus aureus (MRSA) infections occurred in 2005 in the United States, and the number of associated deaths was estimated at 19,000, which is more than the corresponding annual number of associated deaths for human immunodeficiency virus (HIV) and AIDS. 1 With the increasing number of community-onset MRSA infections, 2 prevention of staphylococcal infections is now more important than ever.For more than 50 years, it has been known that carriage of S. aureus plays an important role in the pathogenesis of staphylococcal infections and represents a potential target for preventive interventions.One of the first reports (1952) that clearly demonstrated the relationship between S. aureus carriage and subsequent infection involved miners who experienced beat disorders of the knees and elbows.3 A carefully performed microbiological survey showed that there were 24 "heavy" carriers of S. aureus among 45 beat case patients, compared with 5 heavy carriers among 45 matched control subjects without disease (odds ratio, 9.1 [95% confidence interval {CI}, 3.1-26.5]).Phagetyping showed that, in the majority of cases, the carriage strain matched the strain that caused disease.Hospital-based studies in the 1950s and 1960s confirmed this relationship, especially for surgical patients.4 More recently, these studies have been repeated in various other patient populations-for example, dialysis patients, patients with HIV, organ transplant recipients, and critically ill patients with intravascular catheters-with similar results.4 It seems obvious that eradication of S. aureus carriage can reduce the risk for infection.This strategy has been studied in several groups of patients, and a recent Cochrane review aggregated the evidence with regard to the effect of eradication of carriage on the S. aureus infection rate.5 Eight randomized controlled trials studied the effect of mupirocin nasal ointment in various groups of patients.The pooled estimate showed a significant reduction of the S. aureus infection rate