Ceftazidime: in vitro comparison with cephalothin, cefuroxime, and netilmicin. A Norwegian study

The in vitro activity of ceftazidime has been compared with those of cephalothin, cefuroxime, and netilmicin against a variety of gram-positive and gram-negative bacteria in order to register sensitivity patterns in the western part of Norway. An agar dilution method was used for minimal inhibitory concentration (MIC) determination. Ceftazidime was the most active agent against Enterobacteriaceae; all isolates being inhibited by 2 mg/l or less, whereas netilmicin was slightly less active, especially against Providencia. Cephalothin and cefuroxime were markedly less active than the other two agents against Enterobacteriaceae. Ceftazidime and netilmicin were active against our Pseudomonas aeruginosa isolates (MICs less than or equal to 4 and less than or equal to 8 mg/l, respectively). Only netilmicin had useful activity against Acinetobacter calcoaceticus. Ceftazidime was the least active agent against Staphylococcus aureus; nearly all the isolates had MICs of 4-8 mg/l. Cefuroxime was the most active agent against Bacteroides fragilis, whereas ceftazidime was inactive. Ceftazidime may, in the future, be a useful alternative to the aminoglycosides in the treatment of serious gram-negative infections, particularly when P. aeruginosa might be involved.