Staphylococcus aureus carriage rates and antibiotic resistance patterns in patients with acne vulgaris

Background: Overuse of antibiotics has led to the development of antibiotic-resistant strains of Staphylococcus aureus, which are occurring more frequently within the community. Objective: We sought to determine whether long-term antibiotic therapy for acne alter the carriage rate and antibiotic resistance profiles of S aureus. Methods: This was a prospective, cross-sectional, quasiexperimental study. Samples of anterior nares were obtained from dermatology patients given a diagnosis of acne vulgaris (n = 263) who were treated with antibiotics (n = 142) or who were not treated with antibiotics (n = 121). Specimens were tested for the presence of S aureus by growth on mannitol salt agar and then isolated on 5% sheep blood agar. Identification was confirmed based on colonial morphology, Gram stain, catalase, and coagulase testing. Antibiotic susceptibility testing was performed using the VITEK 2 system (bioMerieux, Marcy-l'Etoile, France). Results: The S aureus carriage rate was significantly lower in patients with acne treated with antibiotics (6.3%) compared with those not treated with antibiotics (15.7%; P = .016). The percentage of S aureus isolates resistant to 1 or more antibiotics did not significantly differ between the 2 groups (P = .434). Limitations: Cross-sectional study, patient compliance, and effects of prior acne treatments are limitations. Conclusion: Treatment of patients with acne using antibiotics decreases the S aureus carriage rate but does not significantly alter the antibiotic resistance rates.