Comparative study of piperacillin versus cefoxitin in the treatment of obstetric and gynecologic infections.

Piperacillin sodium (Pipracil, Lederle Laboratories, Wayne, New Jersey), a new semisynthetic penicillin, demonstrated in vitro activity against a broad spectrum of clinical pathogens. It is active against most strains of the clinically important gram-negative aerobic or facultative bacteria and against virtually all the clinically important anaerobic organisms, including Bacteroides fragilis and Bacteroides bivius. This broad antibacterial spectrum suggested that piperacillin might be an effective single antimicrobial agent for the treatment of mixed aerobic/anaerobic infections in obstetric and gynecologic patients. In this study, the clinical efficacy and safety of piperacillin was compared with that of cefoxitin in the management of pelvic infections. There were 23 patients in the piperacillin group (acute salpingitis, 12; endomyometritis, 7; pelvic cellulitis, 2; tuboovarian abscess, 2) and 25 patients in the cefoxitin group (acute salpingitis, 13; endomyometritis, 10; tuboovarian abscess, 2). An average of six bacteria were isolated from each patient. Aerobic bacteria only were recovered from 12.5%, anaerobic bacteria only in 6.5%, and both aerobic and anaerobic bacteria were present in 82.5% of patients. Overall, 21 of 23 (91%) of the piperacillin treatment group and 23 of 25 (92%) of the cefoxitin group responded to therapy with antimicrobial agents alone. The major cause of failure was the presence of an abscess. Piperacillin was shown to be an effective single agent for the management of pelvic infections caused by mixed aerobic and anaerobic bacteria. In addition, piperacillin proved to be safe and well tolerated.