The treatment of acne: driver of resistance in resident commensal flora?

Long courses of topical or oral antibiotics for the management of acne vulgaris are known to exert considerable selective pressure for the overgrowth of resistant skin propionibacteria. The aim of this study was to assess the impact of acne antibiotic treatments on the prevalence of antibiotic resistant commensal bacteria among acne patients and their close contacts, compared with a general population sample. Skin, nasal and oral swabs were collected from 102 acne patients, 93 contacts of acne patients and 105 volunteers and inoculated onto antibiotic-containing and antibiotic-free plates. Resistance rates to erythromycin and clindamycin in coagulase-negative staphylococci collected from facial skin were significantly higher in patients than in volunteers. As well, carriage prevalence of clindamycin resistant oral viridans streptococci in acne patients was significantly higher than in volunteers. Since viable Staphylococcus aureus has been isolated from the nares of a small number of subjects in each group, significance of the results is questionable. No differences of resistance to tetracycline were found among commensal bacteria between patients and healthy controls. These findings show that erythromycin and clindamycin prescription for acne treatment may select antibiotic resistance within the resident flora of skin and non-skin sites