title: Comparative in vitro activity and beta-lactamase stability of CGP 31523A, a new aminothiazolyl cephalosporin.
abstract: The in vitro activity of CGP 31523A, an aminothiazolyl cephem, was compared to that of other cephalosporins--imipenem, aztreonam, carbenicillin, and gentamicin. CGP 31523A inhibited E. coli, K. pneumoniae, P. mirabilis, C. diversus, K. oxytoca, P. stuartii, Salmonella and Shigella at less than or equal to 0.25 micrograms/ml. It was equal or 2-fold more active than cefotaxime and ceftazidime, and 4-fold more active than imipenem against these organisms. It inhibited all carbenicillin and gentamicin-resistant isolates of these species. Neisseria and Haemophilus were inhibited by less than or equal to 0.12 micrograms/ml. Some C. freundii, E. cloacae, E. aerogenes, P. vulgaris, and P. penneri had MICs greater than or equal to 16 micrograms/ml similar to cefotaxime, ceftazidime and aztreonam. Pseudomonas were resistant, MIC 128 micrograms/ml. CGP 31523A inhibited streptococci at less than or equal to 0.25 micrograms/ml with the exception of S. faecalis, and staphylococci were inhibited by 0.5 micrograms/ml but methicillin-resistant isolates were resistant. Bacteroides and some Clostridium had MICs greater than or equal to 16 micrograms/ml. CGP 31523A was less stable than cefotaxime and ceftazidime to the plasmid TEM/SHV/PSE-4 beta-lactamases. Like cefotaxime it was hydrolyzed by the P. vulgaris type Ic beta-lactamase but not by the type Ia enzymes. CGP 31523A was not an effective beta-lactamase inhibitor nor did it induce beta-lactamases. It had overall activity comparable to available extended spectrum cephalosporins.
mesh_terms: D001398:Aztreonam / Q000494:pharmacology; D001419:Bacteria / Q000187:drug effects* / Q000201:enzymology; D002228:Carbenicillin / Q000494:pharmacology; D002439:Cefotaxime / Q000494:pharmacology; D002442:Ceftazidime / Q000494:pharmacology; D002511:Cephalosporins / Q000494:pharmacology*; D005839:Gentamicins / Q000494:pharmacology; D006801:Humans; D015378:Imipenem; D008826:Microbial Sensitivity Tests; D010403:Penicillin Resistance; D013845:Thienamycins / Q000494:pharmacology; D065093:beta-Lactamase Inhibitors; D001618:beta-Lactamases / Q000032:analysis*
chemical_list: D002511:Cephalosporins; D005839:Gentamicins; D013845:Thienamycins; D065093:beta-Lactamase Inhibitors; D015378:Imipenem; C044430:CGP 31523A; D002442:Ceftazidime; D001618:beta-Lactamases; D001398:Aztreonam; D002228:Carbenicillin; D002439:Cefotaxime