Introduction: Pseudomonas aeruginosa is one of the important bacteria for nosocomial infections; particularly in patients with immune deficiency. For the treatment of serious infections caused by these bacteria, antibiotics such as aminoglycosides many, quinolones and beta-lactams are used. However the emergence and spread of resistant nosocomial strains of resistance have been reported. Nowadays, efflux pump has been proposed as an important mechanism of resistance to antibiotics in bacteria.
 
Materials & methods: In this cross-sectional study, 60 clinical isolates of P.aeruginosa were collected from fecal samples from laboratories in Kerman province. All isolates were approved with the phenotype and biochemical tests. The disk diffusion method was performed according to CLSI (Clinical and Laboratory Standards Institute). Multiplex-PCR tests were performed for detection of efflux pumps genes (mexA, mexB, mexR) using specific primers.
 
Findings: All the 60 fecal isolates of P..aeruginosa were confirmed by biochemical tests. The greatest sensitivity was observed for ceftizoxime 55(91.7%), imipenem, 54(90%), meropenem, 48(80%) and ciprofloxacin 40(66.7%). The greatest resistance were determined to antibiotics cefepime 36(60%) and ciprofloxacin 19(31.7%). The highest frequency was observed of Mex B gene in 59(98.3%) of the isolates.
 
Discussion & conclusions: Rapid diagnosis of Pseudomonas aeruginosa in clinical samples is more than important for initiation of treatment. In general, the use of multiplex polymerase chain reaction for detection of antibiotic-resistant P. aeruginosa is very important in clinical samples of patients.