gyrA mutations and mexX deregulation involved in multidrug resistant isolates of Pseudomonas aeruginosa in Guilan hospitals

Introduction: Pseudomonas aeruginosa is a gram-negative bacterium that continues to be a major cause of opportunistic nosocomial infections. In pseudomonas aeruginosa, several quinolone resistance mechanisms have been proposed. The aim of this study investigation of gyrA mutations and MexX expression in drug resistant pseudomonas aeruginosa isolated from burned patients in Guilan hospitals.Materials and Methods: In this study, forty-five pseudomonas aeruginosa, isolated from different clinical samples identified by biochemical tests. The antibiotic resistance and susceptibility of strains was determined by Kirby Bauer method and PCR-sequencing was carried out to assess gyrA mutations in drug resistant strains. Then, the expression of MexX was evaluated by quantitative RT-PCR.Results: 7KH KLJKHVW UHVLVWDQFH IRU FLSUR R[DFLQ (&3) ZDV VHHQ LQ 1024 J/ml. MIC range in pseudomonas aeruginosa resistant strains were between 32 to 1024ʽg/ml. After PCR and electrophoresis, sequencing was done in part of the gyrA gene and the mutation T83I and D87Y was found in the most strains. Also, upregulation of MexX was revealed in the resistant strains.Conclusions: Quinolones act with inhibiting the target enzyme DNA gyrase subunits (gyrA and gyrB), subsequently inhibit DNA replication. Also, upregulation of MexXY-OprM system in pseudomonas aeruginosa may lead to multidrug resistance in clinical isolates. Mutation in gyrase could be develop quinolone resistance. In this study has been revealed that quinolone resistance is associated with mutations in gyrA and mexX overexpression. Therefore, it seems that gyrA mutations and mexX overexpression play important role in ciprofloxacin resistance development in Guilan.

کلیدواژه ها:

mexX ، gyrA ، Pseudomonas aeruginosa ، quinolone resistance