Journal article
Development of antibiotic resistance and up-regulation of the antimutator gene pfpI in mutator Pseudomonas aeruginosa due to inactivation of two DNA oxidative repair genes (mutY, mutM)
University of Copenhagen1
Hospital Universitario Son Espases2
Technical University of Denmark3
Mathematical Statistics, Department of Informatics and Mathematical Modeling, Technical University of Denmark4
Department of Informatics and Mathematical Modeling, Technical University of Denmark5
Copenhagen University Hospital Herlev and Gentofte6
Prevention and correction of oxidative DNA lesions in Pseudomonas aeruginosa is ensured by the DNA oxidative repair system (GO). Single inactivation of mutT, mutY and mutM involved in GO led to elevated mutation rates (MRs) that correlated to increased development of resistance to antibiotics. In this study, we constructed a double mutant in mutY and mutM (PAOMY-Mgm) and characterized the phenotype and the gene expression profile using microarray and RT-PCR.
PAOMY-Mgm presented 28-fold increases in MR compared with wild-type reference strain PAO1. In comparison, the PAOMYgm (mutY) single mutant showed only a fivefold increase, whereas the single mutant PAOMMgm (mutM) showed a nonsignificant increase in MR compared with PAO1 and the single mutants. Mutations in the regulator nfxB leading to hyperexpression of MexCD-OprJ efflux pump were found as the mechanism of resistance to ciprofloxacin in the double mutant.
A better fitness of the mutator compared with PAO1 was found in growth competition experiments in the presence of ciprofloxacin at concentrations just below minimal inhibitory concentration. Up-regulation of the antimutator gene pfpI, that has been shown to provide protection to oxidative stress, was found in PAOMYMgm compared with PAO1.
In conclusion, we showed that MutY and MutM are cooperating in the GO of P. aeruginosa, and that oxidative DNA lesions might represent an oxidative stress for the bacteria.
Language: | English |
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Year: | 2011 |
Pages: | 28-37 |
ISSN: | 15746968 and 03781097 |
Types: | Journal article |
DOI: | 10.1111/j.1574-6968.2011.02383.x |
ORCIDs: | Christiansen, Lasse Engbo , 0000-0002-9316-1529 , 0000-0002-1347-725X and 0000-0001-5648-4858 |
Anti-Bacterial Agents Bacterial Proteins DNA Glycosylases DNA-Formamidopyrimidine Glycosylase Drug Resistance, Bacterial Gene Expression Profiling Gene Expression Regulation, Bacterial Gene Knockout Techniques Microarray Analysis Mutation Reverse Transcriptase Polymerase Chain Reaction Rifampin mutY adenine glycosylase