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).

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.