Background: More than 80 percent of health care–associated Staphylococcus aureus infections are attributed to endogenous sources (e.g., preexisting patient nasal or skin colonization) among S. aureus carriers. However, several trials have failed to show that prophylactic nasal mupirocin (Bactroban) reduces surgical infection rates among S. aureus carriers. This may be because of infections arising from the skin reservoir, or because infections were already incubating by the time mupirocin was started based on screening culture results. Bode and colleagues studied if mupirocin or chlorhexidine gluconate soap (Betasept) can prevent hospital-associated S. aureus infections.

The Study: The authors screened adult patients admitted to surgical and medical services for S. aureus using a real-time polymerase chain reaction assay. S. aureus carriers were randomized to start intranasal 2% mupirocin and chlorhexidine gluconate soap (40 mg per mL) or placebo versions within 24 hours of admission. Nasal products were used twice daily, and soap was used as a daily body wash for the first five days of hospitalization. Patients were followed for six weeks after discharge to monitor for S. aureus infections. Participants were excluded if they had a known allergy to study products, had used mupirocin within the previous four weeks, or were pregnant or breastfeeding.

Results: A total of 917 patients were randomized, of whom 88.1 percent underwent a surgical procedure. The mupirocin-chlorhexidine group had a significantly lower S. aureus infection rate (3.4 versus 7.7 percent in the placebo group; relative risk = 0.42). Length of hospital stay was also significantly shorter in the treatment group (12.2 versus 14.0 days, respectively). Although all-cause mortality did not differ between the groups, only one patient in the mupirocin-chlorhexidine group died from an S. aureus infection, compared with three patients in the placebo group. Adverse reactions were limited to local irritations of the nose or skin, which resolved after study treatments ended.

Conclusion: The authors conclude that rapid detection of S. aureus carriers followed by early decontamination of nasal and extranasal sites significantly reduces related health care–associated infections in hospitalized patients, as well as the mean hospital stay. The benefit of such a regimen in nonsurgical patients remains unclear because of the high proportion of surgical patients in this study.