title: [Enzymologic aspect of piperacillin combinations].
abstract: Like all penicillins, piperacillin exhibits some susceptibility to beta-lactamases of the penicillinase type, including those produced by Staphylococcus aureus and the TEM, OXA and CARB enzymes isolated from Gram-negative bacilli. Piperacillin is very slightly hydrolyzed by cephalosporinases, which makes it similar to 3rd generation cephalosporins. When tested with Enterobacter cloacae GN 5797 and Pseudomonas aeruginosa NTC 8303, two strains which produce inducible cephalosporinases, piperacillin had moderate inductive activity compared to cefoxitin, a potent inducer. Induction was very low with Enterobacter, but the drug was slightly more sensitive to Pseudomonas. Inhibition of this type of beta-lactamase synthesis was very strong when piperacillin was combined with amikacin and weaker when it was combined with pefloxacin. The piperacillin-amikacin combination prevented the development of piperacillin-resistant mutants of Enterobacter and Pseudomonas and, probably, of all Gram-negative bacilli. In our tests, the piperacillin-pefloxacin combination was of interest only against Enterobacter, and probably against all enterobacteria, since Pseudomonas mutants that resist pefloxacin are fairly easily obtained in vitro.
mesh_terms: D000583:Amikacin / Q000494:pharmacology; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D004359:Drug Therapy, Combination; D004754:Enterobacter / Q000378:metabolism; D004790:Enzyme Induction; D006868:Hydrolysis; D009643:Norfloxacin / Q000031:analogs & derivatives / Q000494:pharmacology; D015366:Pefloxacin; D010878:Piperacillin / Q000378:metabolism / Q000494:pharmacology*; D011550:Pseudomonas aeruginosa / Q000378:metabolism; D001618:beta-Lactamases / Q000096:biosynthesis*
chemical_list: D000900:Anti-Bacterial Agents; D015366:Pefloxacin; D000583:Amikacin; D001618:beta-Lactamases; D009643:Norfloxacin; D010878:Piperacillin
vernacular_title: Aspect enzymologique des associations de pipéracilline.