[Effect of ceftazidime on enterobacteria and Pseudomonas producers of beta-lactamases]

The activity of cephalotin, cefoxitin, cefamandole, cefoperazone, cefotaxime, latamoxef, thienamycin, azthreonam, cefsulodine and ceftazidime against beta-lactamase producing strains of Enterobacteriaceae and Pseudomonas was compared by determination of 99% inhibitory concentrations. The isogenic strains studied differed by a single genetic event: mutation, gene amplification, acquisition of a high or low copy-number plasmid or of a transposon and were representative of the major known mechanisms of resistance toward beta-lactams. The results obtained indicate an overall excellent activity of ceftazidime, in particular against Pseudomonas.