In vitro antimicrobial activity of cefozopran and its therapeutic efficacy in respiratory infections

The newly developed cephalosporin antibiotic agent, cefozopran (CZOP), was evaluated in vitro and in vivo. The minimum inhibitory concentrations (MICs) of CZOP, ceftazidime, cefotaxime, cefuzonam, ampicillin and imipenem against 20 strains each of methicillin-susceptible Staphylococcus aureus, methicillin-resistant Staphylococcus aureus, Haemophilus influenzae, Escherichia coli, Klebsiella pneumoniae, Enter -obacter clocae, Serratia marcesens and Pseudomonas aeruginosa were determined by the micro-broth dillusion method using the Dynatech MIC 2000 system. CZOP showed excellent antimicrobial activity against grampositive bacteria and gram-negative bacteria. The MICs of CZOP were almost equal to the other cephalosporins or were lower. Daily dose of 1 g (4 cases) or 2 g (9 cases) or CZOP were given to 13 patients with respiratory tract infections for 4 to 14 days (mean : 10.8 days). The clinical efficacy was exellent in 2, good in 7 and poor in 3. One case was excluded from the clinical evaluation because of only three days treatment to develope abnormal laboratory findings. Nine causative organisms were identified 5 strais of H. influenzae, 2 strains of S. aureus, one strain of Streptococcous pneumoniae and one strain of P. aeruginosa. The bacterial eradication rate was 8/9. Eosinophilia and an elevation of transaminase were observed in each three patients. From these results, we conclude that CZOP is one of the most useful cephalosporin antibiotic agents in the treatment of respiratory tract infections.