Susceptibility patterns of anaerobic bacteria isolated in South-East Asia

The in vitro activity of 11 antimicrobial agents against 444 recent isolates of anaerobic bacteria from four centres in South-East Asia was determined by an agar dilution technique. Chloramphenicol, imipenem, ticarcillin/clavulanate and metronidazole were very active against most strains tested; however, resistance to imipenem was detected among Bacteroides species. The addition of clavulanate and sulbactam to amoxycillin and ampicillin, respectively, potentiated their activity against many anaerobes, although not all strains resistant to amoxycillin/ampicillin were rendered susceptible. Between 70 and 90% of Bacteroides fragilis and non-fragilis B. fragilis group isolates were susceptible to cefoxitin and cefotetan, however, there was marked clustering around the breakpoints. There was a significant amount of clindamycin resistance in both Bacteroides species and clostridia, reducing the usefulness of this drug. Although no major regional differences in susceptibility patterns were observed, continued periodic surveillance will be required to monitor the emergence of resistance.