Investigation of Class I, II and III Integrons among Acinetobacter Strains Isolated from Ventilator-Associated Pneumonia Patients in Intensive Care Unit of Rasoul Akram Hospital in Tehran, Iran

Multi-drug resistant strains of Acinetobacter spp. have created therapeutic problems worldwide. The objective of this study was to detect integrons in Acinetobacter spp. isolates from Ventilator-Asso­ciated Pneu­monia patients using PCR method. A total 51 Bronchoalveolar lavage samples were obtained from pa­tients in ICU and examined for Acinetobacter spp. infection by bio­chemi­cal and PCR methods using blaOXA51-like primers. An­timi­crobial suscep­tibility testing was performed using disk diffusion and MIC me­thods. Among 51 patients with VAP (62.7% males, 35.2% females, mean age 53 year), 50 (98%) were positive, with a high prevalence of gram-nega­tive bacteria, mainly Acinetobacter spp. (70%), from which A. baumani was detected in 34 (68%) and A. lwoffii in 1 (2%) of iso­lates. More than 90% of isolates were resistant to imipenem, pipera­cil­lin+tazobactam, third genera­tion cephalosporins and gentamicin, while the most effective antibiotic was colistin (100%). The correla­tion coeffi­cient between disk diffusion and MIC was 0.808 (p = 0.001). Three Aci­netobacter isolates (8%) harbored integrase I gene but none of isolates contained Class II or III integrons. The results showed that colistin was an effective antibi­otic and can be used for treatment of patients in ICU. Due to the high number of MDR isolates lacking Integrons it can be concluded that although class I in­tegrons are important among clinical isolates of A. baumannii, they have no significant role in dissemination of antibiotic resistance genes in Rasoul Akram Hospital in Tehran, Iran. The pres­ence of IntI in A. lwoffii may be related to transfer of integron to A. baumannii which can be con­sidered as an important threat for hospi­talized patients.