[Laboratory and clinical studies on cefotetan in respiratory tract infections]

Seventy five patients with respiratory infections, including 40 cases of acute pneumonia, 33 cases of secondary infection after chronic pulmonary diseases and 2 cases of pulmonary abscess, were treated with cefotetan (CTT, Yamatetan) by drip infusion in order to evaluate its clinical efficacy. The overall rate of effectiveness was 83.8%. CTT was examined comparatively with other beta-lactam antibiotics for antibacterial activity on clinically isolated strains of 3 major respiratory pathogens including Haemophilus influenzae, Branhamella catarrhalis and Streptococcus pneumoniae. Minimum inhibitory concentrations (MIC's) of CTT on H. influenzae were less than 3.13 micrograms/ml regardless of the production of beta-lactamase by these organisms. As to B. catarrhalis, CTT also exerted an antibacterial activity enough to control the proliferation of all the strains at a level of 1.56 micrograms/ml. Against S. pneumoniae, on the other hand, CTT exhibited the lowest activity of all the drugs tested but still showed MIC's of 3.13 micrograms/ml or less. Drip infusion of CTT at a dose of 2 g brought about an average maximum blood concentration of 342 +/- 25.7 micrograms/ml and an average half-life in blood of 2.48 +/- 0.41 hours Maximum sputum concentration of the drug, however, was variable among the cases tested, ranging from 0.40 to 1.80 micrograms/ml. Side effects of the drug were observed in 5 cases or 6.7%. Four of them had some allergic symptoms; i.e., pyrexia and eruption. One patient was especially diagnosed as possible drug-induced interstitial pneumonia during the treatment with the drug. The diagnosis was confirmed by transbronchial lung biopsy and lymphocyte blastogenesis by CTT in vitro. As to abnormal laboratory findings, blood transaminases were elevated during drug administration in 13 cases or 17.3%, but were reduced back to the normal level after the withdrawal of the drug.