Molecular Study of Efflux Genes in Pseudomonas aeruginosa Isolated from Clinical Samples

Pseudomonas aeruginosa is a common nosocomial pathogen associated with several clinical infections. It shows high resistance to most antibiotics classes due to multiple antibiotic resistance mechanisms. The aim of the present study was to assess the presence of efflux system genes by multiplex PCR among clinical isolates of P. aeruginosa. The study was conducted on clinical isolates of P. aeruginosa collected from Mansoura University hospital from January 2016 to December 2016. Identification of P. aeruginosa was performed according to standard microbiological techniques and antibiotics susceptibility was determined by disc diffusion methods. Multiplex PCR was used for amplification of MexA, MexB, and MexR genes. For detection of OprM and OprD genes, two separate rounds of PCR were performed. Isolated P. aeruginosa showed high resistance to gentamicin (90.6%), amikacin (66.03%) ceftazidime (77.4%), Aztreonam (64.2%), imipenem (47.2%) and ciprofloxacin (26.4%).PCR study for efflux genes revealed the presence of genes in 66.03% of P. aeruginosa isolates; combined MexB and OprD in 60.4%, MexB alone, and combined MexB and OprD in 1.9% for each. The presence of efflux genes was associated significantly with high resistance to gentamicin, ceftazidime, Cefepime, Aztreonam, Ciprofloxacin, Amikacin, Meropenem and Imipenem (P value 0.0001, 0.003, 0.0001, 0.008, 0.02, 0.03, 0.0001 and 0.0001; respectively). The present study highlights the importance of genes controlling efflux pumps as an important cause associated with P. aeruginosa resistance to antibiotics. Longitudinal large scales studies are required for further analysis of these genes and its expression effects on antibiotics resistance of P. aeruginosa.