Prevalence of integrons 1, 2, 3 associated with antibiotic resistance in Pseudomonas aeruginosa isolates from Northwest of Iran

Abstract

Background: The presence of Class 1, 2 and 3 integrons in clinical isolates of Pseudomonas aeruginosa with multi-drug resistance phenotype has rendered the organism as a new concern.

Objective: This study aimed to investigate the prevalence of Class 1, 2 and 3 integrons in multi-drug resistant clinical isolates of Pseudomonas aeruginosa collected from hospitals in the city of Tabriz Materials and Methods: A total of 200 P. aeruginosa non-duplicated clinical isolates were collected from inpatients and outpatients in different wards of hospitals from May to November 2016. The bacteria were identified by conventional microbiological methods. Antibiotic susceptibility test was performed by disk diffusion method and the presence of integrons was analyzed by polymerase chain reaction (PCR).

Results: Colistin was the most effective antibiotic, while 98% of the isolates were resistant to cefotaxime. Fifty-three percent of the isolates were recorded as multi-drug resistant (MDR) phenotype; however, 27.5% of the isolates were resistant to more than 8 antibiotics. In this study, 55 (27.5%), 51 (25.5%), and 30 (15%) clinical isolates of P. aeruginosa were positive for Class 1, 2 and 3 integrons, respectively. aac(6)II in Class I integrons and dfrA1 in ClassII and aacA7 in Class II integrons were the most prevalent genes. Resistance to aminoglycosides were the most common genes harbored by integrons.

Conclusion: The results of this study showed that the prevalence of Class 1, 2 and 3 in integron genes in most P. aeruginosa strains islated from different parts and equipment used in the hospital. The role of these transferable genetic agents has been proven in the creation of resistance. Therefore, it is essential to use management practices to optimize the use of antibiotics, preferably based on the results of antibiogram and trace coding genes for antibiotic resistance.

Fig. 1

PCR product of the amplification of int-1after agarose electerophoresis. M: ladder (100 bp). C+: control positive of a gene (int-1). C-: control negative. 1-6: Pseudomonas aeruginosa isolates (sample number 3 was positive).