title: [Clinical laboratory approach for estimating effective administrative dosage of cefmenoxime. Observation on the MICS and cefmenoxime disc susceptibility test].
abstract: The in vitro activity of cefmenoxime (CMX) was determined using agar dilution at inoculum level of 10(6) cfu/ml against 333 clinical bacterial isolates. CMX was highly active against Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis, Enterobacter aerogenes and Haemophilus influenzae and also Streptococcus Pyogenes and Streptococcus pneumoniae with MIC values in the range of 0.024 to 3.13 micrograms/ml. Against Staphylococci and Serratia marcescens, CMX showed the antimicrobial activity with MIC90 6.25 micrograms/ml. However, CMX was not active against Pseudomonas aeruginosa and Acinetobacter anitratus and exhibited no useful activity against Streptococcus faecalis. Reliability of CMX disc diffusion susceptibility test for quantitative estimation of the antimicrobial activity was also investigated, using 8 mm diameter disc (Showa) and 6 mm diameter disc (Wako), both of them containing 30 micrograms of CMX. These disc susceptibility test results were well correlated with MICs, capable of utilizing CMX disc susceptibility test for the estimation of proper administrative dose of CMX. Using 6 mm diameter disc containing 30 micrograms CMX, FUCHS et al. have proposed the following tentative zone size break points: greater than or equal to 22 mm = MIC 8 micrograms/ml, susceptible; 15 to 21 mm = MIC 16 approximately 32 micrograms/ml, moderately susceptible (intermediate); and less than or equal to 14 mm = MIC greater than 32 micrograms/ml, resistant. In this investigation, the following zone size break points have preferred: greater than or equal to 25 mm = MIC less than or equal to 3 micrograms/ml (3+); 20 to 24 mm = MIC greater than 3 to 15 micrograms/ml (2+); 16 to 19 mm = MIC greater than 15 to 60 micrograms/ml (+) and less than or equal to 15 mm = MIC greater than or equal to 60 micrograms/ml (-). Based on CMX pharmacokinetic data currently available, MIC break points proposed, less than or equal to 3 micrograms/ml and less than or equal to 15 micrograms/ml, would be useful for estimating the administrative dose of this antibiotic to obtain the effective blood level (e.g. the bacteriostatic activity in serum 1: greater than or equal to 8 for treatment of severe infection.
mesh_terms: D001419:Bacteria / Q000187:drug effects*; D015281:Cefmenoxime; D002439:Cefotaxime / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000097:blood / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004352:Drug Resistance, Microbial; D008826:Microbial Sensitivity Tests
chemical_list: D015281:Cefmenoxime; D002439:Cefotaxime