In-vitro studies with ceftazidime.

MIC determinations for 275 multiply-resistant nosocomial isolates of enterobacteria showed that ceftazidime was more effective than cefotaxime, cefoxitin or cephalothin. Enterobacter species were the most resistant with 12% isolates resistant to more than 8 mg/l of ceftazidime, but this was still the most active agent. Of 150 isolates of Pseudomonas aeruginosa (55% of which were resistant to gentamicin), only 9% were resistant to 8 mg/l of ceftazidime and 2% to cefsulodin, both of which were more active than cefotaxime, ceftriaxone, cefoperazone or moxalactam. Ceftazidime was less active than cefoxitin against Bacteroides fragilis, with 30% of strains resistant to 8 mg/l of ceftazidime, but it was more active than cefotaxime or cephalothin.