SUSCEPTIBILITIES OF BRUCELLA-MELITENSIS ISOLATES TO CLINAFLOXACIN AND4 OTHER NEW FLUOROQUINOLONES

The susceptibilities of 120 clinical isolates of Brucella melitensis a nd 3 reference strains of the same species to six fluoroquinolones (cl inafloxacin, PD 117596, PD 131628, PD 138312, PD 140248, and ciproflox acin) were examined by agar dilution MIC meth odology. Clinafloxacin w as the most active compound tested (MIC at which 50% of strains tested were inhibited [MIC(50)] and MIC(90) of 0.06 mu g/ml). Its level of a ctivity was slightly higher than that of PD 117596 (MIC(50) and MIC(90 ) of 0.12 mu g/ml). PD 131628 and ciprofloxacin were less active than clinafloxacin, with MIC(50)s ranging from 0.12 to 0.25 mu g/ml and MIC (90)s of between 0.25 and 0.5 mu g/ml for the two compounds. The activ ity levels of PD 138312 and PD 140248, with MIC(50)s ranging from 1 to 2 mu g/ml and MIC(90)s of 4 to 8 mu g/ml, were lower than those of th e other fluoroquinolones tested.