[Antimicrobial activity of cefetamet against fresh clinical isolates of Branhamella catarrhalis]

Abstract

Against strains of Branhamella catarrhalis which were separated from various RTIs (respiratory tract infections) in 1991 antimicrobial activities (MICs) of cefetamet (CFMT) were determined, and the following conclusions were obtained. 1. The MIC80 of CFMT against B. catarrhalis was 0.39 microgram/ml, which was higher than that of cefixime (CFIX) by one dilution or twofold, but was lower than that of cefpodoxime (CPDX) by two dilutions or fourfold and that of cefotiam (CTM) by three dilutions or eightfold. 2. The fact that all of the 50 strains tested were beta-lactamase producers appeared to indicate that CFMT was stable against BRO-1 and BRO-2 beta-lactamases produced by B. catarrhalis. 3. Blood concentrations of the test drug, CFMT, and control drugs upon normal single doses were calculated using pharmacokinetic parameters. Lengths of time periods during which drug concentrations stayed above their MICs against B. catarrhalis obtained in this study were determined for CFMT, CFIX, CPDX and CTM. They were, respectively, 12 hours, 12 hours, 6 hours, and 2 hours, thus CFMT appeared to remain above MIC for sufficiently long time for the treatment of RTIs which are affected by B. catarrhalis directly or indirectly.