ANTIBIOTIC SUSCEPTIBILITY OF ANAEROBIC-BACTERIA IN EUROPE

Twenty-two laboratories in 15 European countries determined the MICs o f 12 antibiotics for 1,289 isolates of the B. fragilis group by a micr odilution method. There was no resistance to metronidazole (breakpoint , 8 mg/L), and only one isolate was found to be resistant to chloramph enicol (breakpoint, 8 mg/L). Resistance was uncommon to imipenem (0.3% at concentrations >4 mg/L), amoxicillin/clavulanate (1% at concentrat ions >8 mg/L), cefoxitin (3% at concentrations >32 mg/L), mezlocillin (6% at concentrations >64 mg/L), and clindamycin (9% at concentrations >4 mg/L). The majority of the isolates were resistant to ampicillin ( 93% at concentrations >4 mg/L), ciprofloxacin (56% at concentrations > 4 mg/L), and tetracycline (64% at concentrations >4 mg/L). Bacteroides fragilis was the most susceptible species of the group, and the most striking regional differences in susceptibility were found in associat ion with clindamycin and tetracycline; more resistance was noted in is olates from the southern part of Europe (Greece, Italy, Portugal, and Spain). It has been reported that Fusobacterium species and Clostridiu m species occasionally produce beta-lactamases. A few metronidazole-re sistant Clostridium perfringens strains but no metronidazole-resistant fusobacteria have been isolated.