Detection of Efflux MexAB-associated Multidrug Resistant (MDR) Pseudomonas aeruginosa Isolated from Patients in Torbat Heydarie, Northeast Iran

Aims of the study : Pseudomonas aeruginosa ( P. aeruginosa ) is one of the leading causes of hospital acquired infections. Infections with P. aeruginosa are often hard to treat because of existence of different mechanisms of antibiotic resistance changes in permeability of drugs and activity multidrug efflux pumps . The aim of current study was to determine the antibiotic resistance pattern of P. aeruginosa and existence of efflux pump MexAB genes using PCR technique. Materials and Methods: 506 isolates cultured from different clinical specimens of patients hospitalized at Nohom Dey and Razi hospitals of Torbat Heydarie (northeast Iran) were collected and used in this study. Isolates were identified using conventional bacteriology and their susceptibility to different antibiotics were assessed using agar disk diffusion method. The PCR assay was used to detect efflux pump MexAB genes. Results: From 506 isolates, 50 were identified as P. aeruginosa and these were isolated from isolated from blood, tracheal, burn, and wound. Incidence of P. aeruginosa was greater in males than females , wound infections had the highest number of occurrence and patients between 30-50 years were the most infected age group. In total, 60.86% of strains were multidrug resistant (MDR). The PCR technique revealed that most of the P. aeruginosa isolates and all the MDR strains contained MexA and MexB genes. Conclusions: The emergence of MDR microorganisms poses serious therapeutic problems for patients. Determining bacterial resistance mechanisms is complex. In this way, efflux systems were responsible for antibiotic resistance and played an important role in the MDR phenotype among P. aeruginosa isolates.