Antimicrobial susceptibility patterns and resistance transferability among Bacteroides fragilis group isolates from patients with appendicitis in Bali, Indonesia.

Patterns of antimicrobial susceptibility were determined for 155 clinical isolates of the Bacteroides fragilis group from patients with acute appendicitis in Bali, Indonesia. The transfer of drug resistance was also studied, and plasmid analyses were undertaken. Metronidazole and chloramphenicol were the most active drugs against these isolates (resistance rate, < or = 0.6%). Among the beta-lactam drugs, cefoxitin was the most active (resistance rate, 2%). Rates of resistance to tetracycline were high (16%). Resistance to clindamycin (rate, 10%) increased during the 2-year study period. Except in the case of beta-lactam agents, overall susceptibility patterns were comparable to those reported from other countries. Tetracycline resistance was more frequently transferred after tetracycline induction than without such induction (P < .05, chi 2 test). Resistance to tetracycline and clindamycin was co-transferred by five of 12 donor strains. In one of these five strains, transferability was constitutive, with a high transfer frequency (10(-5) per input donor). Plasmid analysis indicated that the transfer of resistance to tetracycline and clindamycin among the strains studied was not plasmid mediated.