CROSS-RESISTANCE ANALYSIS FOR DU-6859A, A NEW FLUOROQUINOLONE, COMPARED TO 6 STRUCTURALLY SIMILAR COMPOUNDS (CIPROFLOXACIN, CLINAFLOXACIN, FLEROXACIN, LEVOFLOXACIN, OFLOXACIN, AND SPARFLOXACIN)

Emerging resistance to the current fluoroquinolones has encouraged syn thesis of new compounds in this class. We have evaluated the activity of DU-6859a, a novel halogenated quinolone, against a panel of 300 bac teria, relative to the activity of ciprofloxacin, clinafloxacin, flero xacin, levofloxacin, ofloxacin, and sparfloxacin. DU-6859a was the mos t active of the fluoroquinolones studied and retains potentially usefu l activity against 80% of isolates resistant (minimum inhibitory conce ntration, greater than or equal to 4 mu g/ml) to ciprofloxacin. Contin ued clinical investigation of DU-6859a and similar new quinolones is u rged.