Genetic Variation among Antibiotic-Resistant P.aeruginosa Biofilm Former Isolates Obtained from Clinical Samples

Backgrounds and Objectives:Biofilm producer P. aeruginosa isolatesare more resistant to common antibiotic treatments. Several gene clusters likepsl and pel are essential factors for biofilm formation. Polymerase chain reaction and pulsed field gel electrophoresis (PFGE) were employed to understand the genetic variation in the isolates. The aim of this study was to investigate the relationship between genotypes and epidemiological study of the isolates. Materials and Methods:Fifty-Nine P. aeruginosaisolates were recovered from blood, body fluids, sputum, urine and wounds from hospitalized patients, collected and used for testing. Biofilm formation was assessed by simple microtiter plate. The bacterial biofilm formation was measured and the minimum biofilm eradication concentration values of ciprofloxacin and imipenem against the formed biofilm were determined. Restriction analysis was followed by PFGE to determine antibiotic-resistant and biofilm former isolates. Results:Prevalence of multidrug resistant (MDR) isolates was 68.75% and biofilm producers were as follows: strong (50.9%), moderate (23.7%), weak (6.8%), and non-biofilm producers (18.6%). We could identify 13 distinctive restriction profiles among 48(81.4%) isolates using an 80% similarity cut-off point and brlR and pel genes were significantly (P= 0.032, P= 0.044) related with phylogenetic pulsotype. Conclusion:Difference in 0-3 band patterns indicates a single genetic event seen in the isolates. The PFGE patterns indicate there are genetic changes among P. aeruginosa isolate.According to obtained prevalence data, it seems there was a relationship between MDR isolation and brlR existence gene in the isolates. Also, it is concluded existence of pel gene is related with production of biofilm.In this study, more than 81% of the isolates were biofilm producers. Interestingly, > 70% of isolates from wound infections were found to be strong biofilm producers.In conclusion, our findings show that regardless of isolation site of P. aeruginosa infection, there are diversity and genetic variation among the isolates resulting in antibiotic resistance related to biofilm formation. These data emphasized that more use of antibiotic should be restricted to prevent development of antibiotic resistant strains. As revealed, 68.75% of MDR isolates had ≥80% phylogenetical similarity, so it might be possible that important genes responsible for MDR phenomenon like brlR and mexA genes were transferred between patients and sources of infections in hospital.