The activity of cefotiam on beta-lactamase-producing bacteria in an in-vitro model.
The activity of cefotiam was tested in an in-vitro model simulating human serum pharmacokinetics. Bacterial strains used for inoculation either produced a penicillinase or a cephalosporinase. The rate of hydrolysis and the MICs of cefotiam were determined in comparison with those of ampicillin and cephalothin. The influence of these beta-lactamases on the killing kinetics and the degradation of cefotiam in the in-vitro model were then measured. Although all beta-lactamases hydrolyzed cefotiam, only the chromosomal cephalosporinases, especially those from Enterobacter and Klebsiella, reduced the elimination of the bacteria by degradation of the drug. A rough correlation between the hydrolytic activity and MIC could be demonstrated for cefotiam but not for ampicillin, while a correlation between killing ability and MIC only existed for strains with cefotiam MICs higher than 16 mg/l.
D000667:Ampicillin / Q000494:pharmacology; D002439:Cefotaxime / Q000031:analogs & derivatives* / Q000494:pharmacology; D015310:Cefotiam; D002512:Cephalothin / Q000494:pharmacology; D004754:Enterobacter / Q000187:drug effects*; D004755:Enterobacteriaceae / Q000187:drug effects*; D004926:Escherichia coli / Q000187:drug effects*; D006868:Hydrolysis; D007709:Klebsiella / Q000187:drug effects*; D008826:Microbial Sensitivity Tests; D001618:beta-Lactamases / Q000378:metabolism*
D000667:Ampicillin; D015310:Cefotiam; D001618:beta-Lactamases; D002439:Cefotaxime; D002512:Cephalothin