Comparative activity of moxifloxacin in vitro against obligately anaerobicbacteria

The antimicrobial activity of moxifloxacin and seven other antibiotics (fou r of them quinolones) against 292 strains of obligately anaerobic bacteria was assessed employing a broth microdilution technique performed in Wilkens -Chalgren broth. MIC50/MIC90 values (mg/l) for moxifloxacin were as follows : Bacteroides fragilis (n=62) 0.25/2, Bacteroides ovatus (n=70) 1/4, Bacter oides vulgatus (n=29) 0.25/1, Bacteroides thetaiotaomicron (n=17) 2/2, Bact eroides caccae (n=11) 1/2, Prevotella spp. (n=11) 0.25/2, Fusobacterium spp . (n=17) 1/4, Bilophila wadsworthia (n=29) 0.5/1, and Clostridium spp. (n=2 9) 0.125/0.5, respectively. MIC50/MIC90 values (mg/l) for Bacteroides dista sonis (n=8) and Peptostreptococcus spp. (n=9) were 0.25. The results indica ted that moxifloxacin was almost as active as trovafloxacin, as active as g atifloxacin, and more active than levofloxacin and ciprofloxacin against th e anaerobes tested.