Antimicrobial susceptibility of anaerobic bacteria in Auckland 1987-90

The antimicrobial susceptibility of 292 clinical isolates of anaerobic bacteria was determined by a standard agar dilution method. Metronidazole was the most active agent with only one Bacteroides fragilis, two anaerobic cocci, and Propionibacterium acnes being resistant. For B fragilis itself and other members of the B fragilis group: 35/35 (100%) and 43/44 (98%) respectively, were susceptible to amoxycillin-clavulanic acid; 47/47 (100%) and 55/56 (98%) respectively, were susceptible to cefoxitin; and 20/28 (71%) and 7/25 (28%) respectively, were susceptible to ceftriaxone. All four agents and penicillin were almost always active against anaerobic cocci and Fusobacterium species. All agents were active against clostridium isolates except for cefoxitin where only 47/57 (82%) were susceptible. These results allow comparison with isolates from other locations and may be considered when choosing an antimicrobial agent for prophylaxis or therapy of anaerobic infections.