SEQUENTIAL ANTIBIOTIC-THERAPY FOR ACNE PROMOTES THE CARRIAGE OF RESISTANT STAPHYLOCOCCI ON THE SKIN OF CONTACTS

The selection of a predominantly resistant staphylococcal skin flora i n acne patients during antibiotic treatment has been extensively docum ented. This study sought to determine whether antibiotic therapy for a cne had any effect on skin carriage of resistant coagulase-negative st aphylococci (CNS) by close contacts of treated patients. Bacterial sam ples were obtained using a scrub wash technique from facial skin of 41 contacts (parents, siblings or partners) of patients who had been tre ated with at least three different antibiotics over a minimum period o f 2 years. Samples were also obtained from 41 control subjects who had no known contact with any antibiotic treated acne patient. None of th e contacts or controls had received any antibiotic therapy in the prec eding two years. The number, percentage and prevalence of CNS resistan t to each of seven antibiotics was estimated by plating serial ten-fol d dilutions of wash fluid directly onto antibiotic-containing and anti biotic-free medium. Significantly more contacts than controls carried strains resistant to erythromycin, clindamycin, fusidic acid, trimetho prim and chloramphenicol as well as more multiply resistant strains (P < 0.05, chi(2)) The number and percentage of staphylococci resistant to tetracycline, erythromycin, clindamycin, fusidic acid and chloramph enicol were also significantly raised (P < 0.05, Mann-Whitney U-test) in contacts. Only aminoglycoside resistance was not increased by any o f the above criteria. These observations provide evidence that sequent ial antibiotic therapy for acne exerts selective pressure for increase d skin carriage of resistant CNS not only in patients but also in thei r close contacts.