Activities of NXL104 Combinations with Ceftazidime and Aztreonam against Carbapenemase-Producing Enterobacteriaceae

Combinations of NXL104 with ceftazidime and aztreonam were tested against carbapenem-resistant members of the Enterobacteriaceae. Ceftazidime-NXL104 was active against strains with the OXA-48 enzyme or with combinations of impermeability and an extended-spectrum beta-lactamase (ESBL) or AmpC enzyme and also against most Klebsiella spp. with the KPC enzyme, but metallo-beta-lactamase producers were resistant. Aztreonam-NXL104 was active against all carbapenemase producers at 4 and 4 mu g/ml, including those with metallo-beta-lactamases.