Molecular Detection of Integron Genes and Pattern of Antibiotic Resistance in Pseudomonas Aeruginosa Strains Isolated from Intensive Care Unit, Shahid Beheshti Hospital, North of Iran

Pseudomonas aeruginosa is one of the most important pathogens that causes nosocomial infections and shows high level of antibiotic resistance. Integrons are one of the transposable elements in bacteria and their role in antibiotic resistance has been well demonstrated. The aim of this study was a molecular characterization of the integron genes and the determination of the resistance or sensitivity pattern to ceftizoxime, cephizoxim. cephotaxim, amikacin, ofloxacin, imipenem, cefepime, ticarcillin, gentamicin, ciprofloxacin, cefazolin and ceftriaxone antibiotics in P. aeruginosa strains isolated from Intensive Care Units (ICU), Shahid Beheshti Hospital, North of Iran. This cross-sectional study was performed from 2011 to 2012. Totally, fifty four P. aeruginosa strains were isolated from ICU at Shahid-Beheshti hospital, Babol, North of Iran. The bacteria were diagnosed based on mobility, pigment production, growth in 42(0) C, oxidase and catalase tests. PCR analysis was carried out to detect integron genes using hep 35 and hep 36 primers. Also, disk diffusion method was performed to evaluate antibiotic susceptibility of the bacteria using ceftizoxime, ceftazidime, cephotaxime, amikacin, ofloxacin, imipenem, cefepime, ticarcillin, gentamicin, ciprofloxacin, cefazolin and ceftriaxone antibacterial reagents. This study revealed that 20 (37%) P. aeruginosa isolates had integron genes. The antibiotic susceptibility test showed that 53 (98.1%) of the isolates were multidrug-resistant. 12 out of 54 isolated bacteria were resistant to all antibiotics tested. All bacteria were resistant to cefepime and the highest resistance rate was seen to ceftizoxime 92.6% followed by cefazolin 92.3%. The lowest resistance rate was observed to ciprofloxacin 38.9%, ofloxacin 44.4%, amikacin 46.3% and ticarcillin 48.1%. According to this study, P. aeruginosa isolates showed high level of antibiotic resistance and the presence of integrons in these strains can explain the influence of these genes in resistance creation. There was a significant association between resistance to cefotaxime, amikacin, ofloxacin, imipenem, ticarcillin, gentamicin and the presence of integrons.