In vitro activity of cefpirome against beta-lactamase-inducible and stably derepressed Enterobacteriaceae.
Most members of the Enterobacteriaceae and Pseudomonas aeruginosa possess an inducible chromosomal class I beta-lactamase. Bacterial strains which produce high levels of beta-lactamase constitutively can be isolated from infections; these derepressed mutants are responsible for resistance to third-generation cephalosporins and ureidopenicillins. Minimum inhibitory concentrations of cefpirome, a fourth-generation cephalosporin, and other beta-lactam antibiotics were determined for a series of mutants of Citrobacter freundii, Enterobacter cloacae, Morganella morganii, Proteus vulgaris and Serratia marcescens with inducible stably derepressed or basal expression of chromosomal class I beta-lactamases. All the antibiotics tested were almost equally active against beta-lactamase-inducible organisms and their basal mutants. Imipenem and cefpirome showed better activity against derepressed mutants than third-generation cephalosporins and ureidopenicillins.
Binfiglio
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G
Institute of Microbiology, University of Catania, Italy.
Stefani
S
S
Nicoletti
G
G
D000900:Anti-Bacterial Agents / Q000494:pharmacology; D002511:Cephalosporins / Q000494:pharmacology*; D004755:Enterobacteriaceae / Q000145:classification / Q000187:drug effects* / Q000201:enzymology; D004790:Enzyme Induction; D006801:Humans; D008826:Microbial Sensitivity Tests; D013045:Species Specificity; D001618:beta-Lactamases / Q000096:biosynthesis / Q000145:classification / Q000494:pharmacology*; D000097572:Cefpirome
D000900:Anti-Bacterial Agents; D002511:Cephalosporins; D001618:beta-Lactamases; D000097572:Cefpirome