Background : Bacteroides fragilis group(BFG) organisms are very important pathogens in anaerobic infections, and the resistance to several β-lactam agents and clindamycin has increased in these organisms. This study was to investigate antimicrobial susceptibility patterns of BFG organisms and the transferability of clindamycin resistance.
Methods : Antimicrobial susceptibility testing of BFG organisms, isolated from 1992 to 1993, was performed by agar dilution, plasmid analysis by an alkaline lysis and agar gel electrophoresis, and resistance transferability testing of clindamycin resistant strains by a filter paper mating method.
Results : None of the isolates found to be resistant to imipenem, chloramphenicol or metronidazole among the BFG organisms isolated from Korean patients, however, the resistance rates to the third-generation cephalosporins and clindamycin were higher than those in other countries. Resistance transfer from clindamycin-resistant isolates was relatively common(24%), and the resistance was also transferred from a strain without plasmids.
Conclusion : The resistance rates of BFG organisms in Korea are higher than those in other countries and have risen. We conclude that the clinamycin resistance element may be located in the chromosome, since clindamycin resistance is transferred by the conjugation procedure from the strain without plasmids.