Quantitative nasal cultures from carriers of Staphylococcus aureus: effects of oral therapy with erythromycin, rosamicin, and placebo.

Serial quantitative nasal cultures were performed on 87 healthy nasal carriers of Staphylococcus aureus, who were randomly assigned to 7 days of oral therapy with erythromycin, rosamicin (an investigational macrolide antibiotic), or placebo. Staphylococcal carrier rates decreased during therapy with both antibiotics; however, erythromycin was significantly more effective in lowering carrier rates than was rosamicin. The anti-staphylococcal effects of both antibiotics were similar when the mean numbers of S. aureus isolated from positive cultures during therapy were compared. Side effects to each regimen were minimal.