Evaluation of antimicrobials combined with hyperbaric oxygen in a mouse model of clostridial myonecrosis

The efficacy of hyperbaric oxygen (HBO) alone and in combination with several antimicrobial agents was evaluated in a lethal model of gas gangrene in mice. Intraperitoneal administration of penicillin, imipenem, clindamycin, or metronidazole immediately followed inoculation of > 10(9) CFU of Clostridium perfringens type A in mice. Mice treated with hyperbaric oxygen were exposed twice a day to 100% oxygen at 303 kilopascals (kPa) pressure for 90 minutes. The total exposure time to HBO for surviving animals was 9 hours. Control (saline-injected) mice treated with HBO alone did not have an enhanced survival rate when compared with mice exposed to air at ambient pressure. Survival of infected mice treated with either clindamycin or metronidazole was significantly longer than that of groups treated with penicillin or imipenem (p < 0.05). Hyperbaric oxygen alone or in combination with the four antimicrobial agents evaluated did not statistically improve survival of mice infected with a lethal dose of C. perfringens.