Laboratory evaluation of cefmenoxime: a new cephalosporin. In vitro and in vivo antibacterial activities and pharmacokinetic properties.

Cefmenoxime is a new syn-methoxyimino cephalosporin antibiotic derived from cefotiam, which has been proved to be a very effective and useful antibiotic for the treatment of respiratory infections. This bacteriological and pharmacokinetic study was therefore performed in order to evaluate the potency of cefmenoxime in the treatment of respiratory infections. The minimum inhibitory concentrations of cefmenoxime against 179 isolates of respiratory pathogens (Streptococcus pneumoniae 53, Haemophilus influenzae 64, Klebsiella pneumoniae 43, Escherichia coli 9, Enterobacter spp. 10) were less than 0.20 micrograms/ml, and 43 (73%) of 60 Pseudomonas aeruginosa were inhibited by 12.5 micrograms/ml. In vitro antibacterial activity of cefmenoxime was superior to 18 other antibiotics, including cefotiam and cefotaxime tested in this study. Pharmacokinetic studies on tissue distribution in rats, serum levels and urinary excretion in 3 healthy volunteers, and penetration into bronchial secretes of 9 patients with respiratory infections, revealed that cefmenoxime has a higher penetration into the lung and bronchial secretes compared with cefotiam and cefotaxime. In 1 patient with chronic bronchiolitis, the concentration of cefmenoxime in the intra-bronchial secrete reached 12.5 micrograms/ml. From these results, it is concluded that cefmenoxime is a highly potent and useful antibiotic, and may be more effective in the treatment of respiratory infections than many other cephalosporins, including cefazolin, cefotiam and cefotaxime.