Susceptibility of Propionibacterium acnes clinical isolates to 22 antimicrobial agents.

Susceptibilities of 104 Propionibacterium acnes isolates to each of 22 antimicrobial agents was evaluated by broth microdilution. These isolates were susceptible to all of the test agents except metronidazole. N-Formimidoyl thienamycin, a penem coded Sch 29482, and penicillin ranked first, second, and third, respectively, in activity and were significantly more active than other penicillins, cephalosporins, tetracyclines, clindamycin, or chloramphenicol.