The changing pattern of antibiotic susceptibilities of Bacteroides fragilis in Kuwait

The susceptibility of 340 distinct strains of Bacteroides fragilis isolated during 1981 to 1988, to eight antimicrobial agents was determined. These included isolates from infected hospitalized patients (127), infected out-patients (89), faecal isolates from uninfected patients hospitalized for greater than 10 days (48) and from normal subjects in the community (76). All strains were susceptible to metronidazole with a MIC of 1 mg/l. The least effective antibiotics were ampicillin, fusidic acid, erythromycin and tetracycline. There was no significant difference in antibiotic sensitivities between strains causing community-acquired and those causing hospital-acquired infections. However faecal isolates from hospitalized patients were significantly more resistant to ampicillin (P less than 0.05), cefoxitin (P less than 0.005) and clindamycin (P = 0.001) than community faecal isolates. During the study period there was a rise in resistance to clindamycin (P less than 0.005), cefoxitin, erythromycin and fusidic acid (P less than 0.001) and tetracycline (P less than 0.05). Antimicrobial resistance of B. fragilis is rising and long periods of hospitalization seem to play an important role in its development.