[Cefoperazone, cefsulodin and ceftazidime--3 cephalosporins active against Pseudomonas in comparison with their monobactam analogs].

This study compares the in vitro activity of three cephalosporins - ceftazidime, cefoperazone, cefsulodin and their monobactam analogues for 144 strains of Pseudomonas aeruginosa. Media variation studies are performed and the effect of human serum and anaerobic conditions on MIC is investigated. A significant inoculum effect is considered as a sign of instability against beta-lactamases. Ceftazidine inhibits nearly all pseudomonads at concentrations between 2 and 4 micrograms/ml being significantly more active than the other antibiotics tested. The level of activity of all monobactams tested is lower than that of the homologous cephalosporins. The counterpart of ceftazidine is also the most effective monobactam but the counterpart of cefsulodin shows no activity against pseudomonads.