Moxalactam for obstetric and gynecologic infections. In vitro and dose-finding studies

Moxalactam (LY 127935), a "third-generation" β-lactam antimicrobial, has been shown to have promising in vitro activity against a wide spectrum of pathogens similar to those isolated from women with pelvic infections. Pharmacodynamic studies have shown that its serum half life is longer than 2 hours, which permits less frequent dosing. The current investigation was carried out in two parts: In the first phase, the minimal inhibitory concentration of moxalactam against 519 clinical isolates was determined and compared to antimicrobials used in infections caused by these microbes. In vitro activity of moxalactam comparable to that of clindamycin was demonstrated against B. fragilis and other Bacteroides species. There was similar activity to penicillin G and clindamycin against anaerobic gram-positive cocci and activity superior to amikacin was demonstrated against Enterobacteriaceae. The second part of this investigation was a clinical one and 100 women with pelvic infections were given treatment with moxalactam. With an initial dose of 3 gm/day, women with posthysterectomy cellulitis and pelvic inflammatory disease did well. Women with pelvic infections following cesarean section responded less readily to this dose; however, when the initial dose was increased to 6 gm/day, a 91% cure rate was effected. The results of these investigations indicate that moxalactam is useful as a single-agent antimicrobial for treatment of polymicrobial female pelvic infection.