Comparative serum bactericidal activity against test anaerobes in volunteers receiving imipenem, clindamycin, latamoxef and metronidazole

Ten healthy volunteers received on separate days the following regimens: imipenem 500 mg, clindamycin 600 mg, latamoxef 1 g, and metronidazole 500 mg. The antibiotics were given intravenously as an infusion over 15 min. Blood samples were obtained before and 30 min, 1 and 6 h after the start of the infusion. Serum bacteriostatic and bactericidal activities were measured against the following strains of strict anaerobes: two strains of Bacteroides fragilis, one strain each of B. vulgatus, B. thetaiotaomicron, B. oralis, Fusobacterium symbiosum, Eubacterium lentum, Clostridium perfringens, and Peptostreptococcus magnus. Sera from patients receiving clindamycin showed the highest inhibitory and bactericidal activities except against B. thetaiotaomicron and F. symbiosum. Imipenem had similar inhibitory and bactericidal activity to that shown by latamoxef. Metronidazole had a moderate activity against all strains although the activity persisted for 6 h. Latamoxef was the most active antibiotic against the test strain of C. perfringens.