Bactericidal activity of sparfloxacin and ciprofloxacin under anaerobic conditions.

The kill kinetics of sparfloxacin and ciprofloxacin have been investigated under anaerobic conditions against Bacteroides fragilis and Escherichia coli. The results for E. coli were compared with those obtained under aerobic conditions. It was found that the quinolones were bactericidal under anaerobic conditions. This bactericidal activity is inhibited by the presence of chloramphenicol, a known protein synthesis inhibitor. Filamentation was seen with B. fragilis after 2 h exposure to either agent.