FIG. 3.

Stimulation of topoisomerase IV (TOPO IV)-mediated DNA cleavage by trovafloxacin (A). Trovafloxacin concentrations of 0.0195, 0.039, 0.078, 0.156, 0.313, 0.625, 1.25, 2.5, 5.0, and 10 μg/ml were tested. (B) Relative potency (that of ciprofloxacin is given as a value of 1) of trovafloxacin for stimulation of topoisomerase IV-mediated DNA cleavage. The lowest concentration of drug required to stimulate enzyme-mediated DNA cleavage was determined by densitometric scanning of photographs of ethidium bromide-stained agarose gels. The numbers above the bars are MICs for S. aureus RN4220.