In vitro activity, efficacy, and pharmacology of moxalactam, a new beta-lactam antibiotic.

Moxalactam, a potent new beta-lactam antibiotic with a relatively wide spectrum of activity against facultative and anaerobic gram-negative bacilli, was evaluated in vitro and in 28 patients with a variety of severe infections with moxalactam-susceptible organisms (minimum inhibitory concentration less than or equal to 31 microgram/ml). Although therapy was successful in most of these patients, caution is suggested because of the development of resistance on therapy in one patient, persistence of Bacteroides fragilis endocarditis in another, and for certain organisms, a significant inoculum effect on the minimum inhibitory concentration and minimum bactericidal concentration of moxalactam.