Cefuroxime: a new cephalosporin antibiotic with enhanced stability to enterobacterial β-lactamases

The activity of a new cephalosporin antibiotic, cefuroxime, was investigated in vitro. Of 156 strains of enterobacteria and Gram-positive cocci recently isolated from infected urine, 152 were inhibited by ≤32 μg cefuroxime/ml. Pseudomonas aeruginosa strains were uniformly resistant. Dense populations of 95 ampicillinresistant strains of enterobacteria were tested in a turbidimetric system. Cefuroxime, at a concentration of 250 μg/ml was able to suppress the growth of 80 of these strains for longer than 20 h, and 6 of the remaining 15 strains for longer than 8 h. Suppression of growth for therapeutically acceptable periods of time was also obtained when representative Escherichia coli strains were tested in an in vitro model simulating conditions of exposure of bacteria to drug in the infected urinary bladder. These results are substantially better than those previously obtained with the same strains exposed to other cephalosporins, and are attributable to the superior resistance of cefuroxime to enterobacterial β-lactamases.