Detection of ESBLs types blaCTX-M, blaSHV and blaTEM resistance genes among clinical isolates of Pseudomonas aeruginosa

Pseudomonas (P.) aeruginosa is a leading cause of nosocomial infections in most part of the world. The production of extended spectrum ll-lactamases (ESBLs) is an essential mechanism of beta-lactam resistance in these bacteria. This study aimed to investigate the prevalence of ESBL types bla(TEM), bla(SHV) , and bla(CTX)-M in P. aeruginosa isolates from the patients hospitalized in Emam Reza Educational Hospital in Tabriz, northwest of Iran. A total of 100 P. aeruginosa nonduplicated isolates were collected from patients hospitalized in Emam Reza Educational Hospital. Antibiotic susceptibility was determined by the disk diffusion method. ESBL production was confirmed by ceftazidime discs alone and in combination with clavulanic acid (ceftazidime + clavulanic acid). The presence of ESBLs genes of blaTEM, blaSHV, and blaCTX-M were screened by Polymerase Chain Reaction (PCR) and sequencing tests. The DNA of bacteria was extracted and entered in a PCR reaction with primers specific for the proposed genes sequences. Among P. aeruginosa isolates, the highest antibiotic resistance was shown to ceftazidime 70 (70 %), and the highest susceptibility was shown to imipenem 55 (55 %). The results of combined disc test indicated that 66 % of isolates were ESBL producers. Screening for ESBLs genes revealed that ten strains (14 %) were positive for bla(SHV) , 26 % were positive for bla(TEM), and 5 % isolates were positive for bla(CTX-M) genes. The results of this study showed a noteworthy prevalence of bla(TEM), bla(SHV ), and bla(CTX-M) genes in the studied region that, suggests the necessity to take the preventing measures for controlling the dissemination of these resistant isolates.