Use of cephalosporins with enhanced anti-anaerobic activity for treatment and prevention of anaerobic and mixed infections.

The microbiology, adverse-effect profiles, pharmacokinetics, published results of comparative clinical trials, and costs of cephalosporins with enhanced antianaerobic activity are reviewed. Cefoxitin, ceftizoxime, cefotetan, and moxalactam have been used as single agents in the treatment or prophylaxis of anaerobic or mixed aerobic and anaerobic infections, including intra-abdominal, female genital tract, and soft-tissue infections. None of these agents is as active against Bacteroides species as is clindamycin or metronidazole, but differences among the four cephalosporins do not appear to be clinically important. These agents differ somewhat in their activity against gram-positive and gram-negative bacteria. The majority of adverse reactions to these agents are immunological; disulfiram-like reactions and alterations in normal hemostasis have also been observed with cefotetan and moxalactam. All of these agents are well absorbed after intramuscular injection and produce serum concentrations adequate to treat most infections. Only ceftizoxime and moxalactam produce cerebrospinal fluid concentrations adequate for treatment of gram-negative meningitis. The primary route of elimination is renal, and each agent requires dosage adjustments in patients with renal impairment. Major differences exist among the elimination half-lives of the agents in patients with normal renal function. The decision to use a cephalosporin for treatment of anaerobic infections should be based on the results of clinical trials that have demonstrated the efficacy of the agent. Data are available to support the use of cefoxitin, ceftizoxime, and moxalactam in the treatment of intra-abdominal infections; cefoxitin and moxalactam to prevent infection of traumatic injury to the abdomen; all four agents in the treatment of female genital tract infections; and all four agents for prophylactic use in surgical procedures that may involve enteric anaerobes, especially B. fragilis. Cephalosporins with enhanced antianaerobic activity appear to have similar in vitro microbiological activity and have efficacy similar to that of combination regimens for the treatment and prophylaxis of intra-abdominal infections, abdominal contamination, obstetric and gynecological infections, and soft-tissue infections.