Elimination of nasal carriage of Staphylococcus aureus with mupirocin ('pseudomonic acid')--a controlled trial.

In a blind controlled trial 2% mupirocin ointment was applied four times a day for five days to the anterior nares of 32 healthy volunteers who were followed-up for at least five weeks. Mupirocin eliminated the persistent carriage of Staphylococcus aureus in all subjects within two days of starting mupirocin. Two weeks after the course S. aureus could not be detected, even in low numbers, in nose swabs from any of the 32 volunteers, and even after five weeks only six had resumed carriage. Of the 14 subjects who ultimately resumed carriage, 57% acquired a different phage type and 29% showed a relapse of colonisation with their pre-treatment strain. There was no evidence of overgrowth with Gram-negative organisms and pre- and post-treatment isolates of S. aureus were sensitive to mupirocin with MICs of 0.06 mg/l or less. There were no side-effects. We suggest that mupirocin may become the topical agent of choice for the elimination of S. aureus from the anterior nares.