In-vitro activity of the novel oxa-beta-lactam antibiotic moxalactam (LY 127935) against dense populations of selected Gram-negative bacilli.

The activity of moxalactam, a new beta-lactam antibiotic with a novel molecular structure, was examined against dense populations of a variety of Gram-negative bacilli. The lytic activity of moxalactam against ampicillin-sensitive strains was similar to ampicillin, but the activity was maintained against ampicillin-resistant strains, including Pseudomonas aeruginosa, irrespective of whether the ampicillin resistance was 'intrinsic' (non-enzymic) or due to beta-lactamase. Of the 18 strains tested only one, a Hafnia sp., failed to respond to moxalactam.