title: Ciprofloxacin, salicylate, and 2,4-dinitrophenol decrease production of AmpC-type beta-lactamase in two Citrobacter freundii clinical isolates.
abstract: The effect of ciprofloxacin and two mar RAB inducers on the susceptibility to beta-lactam antibiotics in two AmpC beta-lactamase semi-constitutive producer Citrobacter freundii clinical isolates (the DM 1 and DM 2 strains) was studied. Possible changes in outer membrane protein expression, permeability to cephaloridine, active efflux, and hydrolytic activity of beta-lactamase-crude extracts were evaluated under the influence of ciprofloxacin, sodium salicylate, and 2,4-dinitrophenol. Results were compared with those of the effect of the same three chemicals on a normally beta-lactamase-inducible wild-type C. freundii strain. The three assayed compounds decreased beta-lactamase hydrolysis on cephaloridine in both the two clinical isolates as well as in the wild-type strain. However, only the DM 1 and DM 2 strains showed increased susceptibility to beta-lactams. Sodium salicylate and 2,4-dinitrophenol, but not ciprofloxacin, reduced the expression of a 45-kDa outer membrane protein in the three studied strains, which was accompanied by a 4- to 20-fold diminution in permeability to cephaloridine. In conclusion, two mar RAB inducers and ciprofloxacin induced the Mar phenotype and repressed AmpC beta-lactamase synthesis in the DM 1 and DM 2 clinical isolates.
authors.affiliation: Microbiology, Department of Clinical Sciences, School of Medicine, University of Las Palmas de G.C., Dr. Pasteur, 35080-Las Palmas G.C., Spain. 928253005@infonegocio.com
authors.forename: María M
authors.initials: MM
authors.lastname: Tavío
authors.forename: Mariagrazia
authors.initials: M
authors.lastname: Perilli
authors.forename: Jordi
authors.initials: J
authors.lastname: Vila
authors.forename: Pino
authors.initials: P
authors.lastname: Becerro
authors.forename: Joaquím
authors.initials: J
authors.lastname: Ruiz
authors.forename: Gianfranco
authors.initials: G
authors.lastname: Amicosante
authors.forename: María T Jiménez
authors.initials: MT
authors.lastname: De Anta
mesh_terms: D019297:2,4-Dinitrophenol / Q000494:pharmacology*; D002939:Ciprofloxacin / Q000494:pharmacology*; D016971:Citrobacter freundii / Q000187:drug effects* / Q000201:enzymology / Q000302:isolation & purification; D024881:Drug Resistance, Bacterial; D004790:Enzyme Induction / Q000187:drug effects; D006801:Humans; D012459:Salicylates / Q000494:pharmacology*; D001618:beta-Lactamases / Q000096:biosynthesis* / Q000378:metabolism; D047090:beta-Lactams / Q000494:pharmacology*
chemical_list: D012459:Salicylates; D047090:beta-Lactams; D002939:Ciprofloxacin; D001618:beta-Lactamases; D019297:2,4-Dinitrophenol