INTERPRETIVE CRITERIA FOR CI-960, FLEROXACIN AND TEMAFLOXACIN SUSCEPTIBILITY TESTS WITH HAEMOPHILUS-INFLUENZAE

Haemophilus influenzae strains with varied ampicillin resistance and beta-lactamase production patterns were tested against three investigational fluorinated quinolones (CI-960, fleroxacin, temafloxacin) using Haemophilus Test Medium (HTM) and National Committee for Clinical Laboratory Standards (NCCLS) methods. The disk diffusion zones and MICs were compared and regression statistics and scattergrams generated. The rank order of the agents according to activity against Haemophilus influenzae was CI-960 (MIC50 0.002-mu-g/ml) > temafloxacin (MIC50 0.015-mu-g/ml) > fleroxacin (MIC50 0.03-mu-g/ml). The recommended susceptibility interpretive criteria for the 5-mu-g disks of each drug were: for CI-960 greater-than-or-equal-to 23 mm (MIC correlate less-than-or-equal-to 1-mu-g/ml); for fleroxacin greater-than-or-equal-to 19 mm (MIC correlate less-than-or-equal-to 2-mu-g/ml); and for temafloxacin greater-than-or-equal-to 16 mm (MIC correlate less-than-or-equal-to 2-mu-g/ml). All recent Haemophilus influenzae isolates tested were susceptible to these potent fluoroquinolones and no interpretive errors were observed.