Occurrence of metronidazole and imipenem resistance among Bacteroides fragilis group clinical isolates in Hungary

During the period between 1987 and 1997, various surveillances of the antib iotic resistance of B. fragilis group isolates revealed that practically al l the isolates tested were susceptible to imipenem, metronidazole and chlor amphenicol; very few isolates (2.5%) exhibited resistance to amoxicillin/cl avulanic acid. However. similarly as in some southern European countries. t he percentages of the isolates that were resistant to ampicillin, tetracycl ine and clindamycin were high throughout this period, and the resistance to cefoxitin increased from 6% to 16%. In 2000, isolates with intermediate or high resistance to imipenem and isolates with increased MICs to metronidaz ole were emerging among the clinical isolates of B. fragilis. The presence of the cfiA gene was demonstrated by PCR in 7 of 242 isolates (2.9%); 2 of them with high MICs to carbapenems harboured the IS942 element immediately upstream of the resistance genes. In the 2 B, fragilis isolates with increa sed MICs to metronidazole, the nim gene could be detected by PCR. The IS118 6 element was found in these isolates upregulating the metronidazole resist ance gene.