Dumas JL van Delden C Perron K Köhler T 2006 In Pseudomonas aeruginosa many of the clinically relevant resistance mechanisms result from changes in gene expression as exemplified by the Mex drug efflux pumps, the AmpC beta-lactamase and the carbapenem-specific porin OprD. We used quantitative real-time-PCR to analyze the expression of these genes in susceptible and antibiotic-resistant laboratory and clinical strains. In nalB mutants, which overexpress OprM, we observed a four- to eightfold increase in the expression of mexA, mexB, and oprM genes. MexX and mexY genes were induced eight to 12 times in the presence of 2 mg L(-1) tetracycline. The mexC/oprJ and mexE/oprN gene expression levels were increased 30- to 250-fold and 100- to 760-fold in nfxB and nfxC mutants, respectively. We further found that in defined laboratory strains expression levels of ampC and oprD genes paralleled beta-lactamase activity and OprD protein levels, respectively. Our data support the use of quantitative real-time-PCR chain reaction for the analysis of the antimicrobial resistance gene expression in P. aeruginosa. https://sonar.ch/global/documents/89222 eng info:eu-repo/semantics/altIdentifier/doi/10.1111/j.1574-6968.2005.00008.x info:eu-repo/semantics/altIdentifier/pmid/16445748 FEMS microbiology letters. - 2006 Anti-Bacterial Agents Bacterial Proteins Drug Resistance, Bacterial Gene Expression Regulation, Bacterial Humans Porins Pseudomonas aeruginosa Reverse Transcriptase Polymerase Chain Reaction beta-Lactamases Analysis of antibiotic resistance gene expression in Pseudomonas aeruginosa by quantitative real-time-PCR. http://purl.org/coar/resource_type/c_6501