Comparative In Vitro Activities of Clinafloxacin and Trovafloxacin against 1,000 Isolates of Bacteroides fragilis Group: Effect of the Medium on Test Results

The in vitro antibacterial activities of clinafloxacin, trovafloxacin, ciprofloxacin, and cefoxitin against 1,000 clinical isolates of Bacteroides fragilis group were compared by agar dilution in brucella blood agar (BBA) and Wilkins Chalgren agar (WCA). Significantly higher geometric mean MICs for the three quinolones and cefoxitin (P < 0.001) were obtained in BBA than in WCA. Regardless of medium, clinafloxacin was slightly more active than trovafloxacin. The activity of clinafloxacin and trovafloxacin was greater than that of cefoxitin against B. distasonis, B. ovatus, and B. thetaiotaomicron but lower against B. vulgatus. High cross resistance between trovafloxacin and clinafloxacin was observed.