Molecular investingation gene cassette in class1 integron and its relation to antibiotic resistance in Pseudomonas aeruginosa strains isolated from clinical samples

Background: Pseudomonas aeruginosa, as opportunistic bacteria, especially in ICU, Infectious ward and burn patients in hospital. In fact, its high resistance to most antibiotics cause problem in treatment. In this study, we consider the class 1 integron gene cassettes and its relation to multi-drug resistance in P. aeruginosa isolated from clinical samples of Rohani hospital in Babol. Materials and Methods: In this study, 30 clinical strains of P. aeruginosa isolate using standard laboratory. Antibiotic susceptibility testing carried out by both disk diffusion and agar dilution methods. Presence of class 1 integron and gene cassettes was evaluated by PCR technique. Data were analyzed using SPSS software.Results: In this study, we consider the results of both disk diffusion and agar dilution methods, using 9 different antibiotics. In disk diffusion method, most sensitivity showed to amikacin in 27 isolates (90%) and the most resistance to cefotaxime, ampicillin and nitrofurantoin in all of the isolates (100%). In agar dilution method, most sensitivity showed to amikacin in 29 isolates (96%) and the most resistance to cefotaxime in 29 isolates(96%). By using PCR, class I integron gene detected in 18 isolates (60%), of which 12 isolates (66%) were multi-resistant (MDR) to antibiotics. In integron class I positive isolates, the Adenylyltransferase (aadB) and dihydrofolate reductase (dfr) gene cassettes detected in 11 isolates (61%) of which 7 isolates (77%) were multi-resistant and 12 isolates (66%) of which 7 patients (63%) were multiple resistance (MDR), respectively.Conclusion: The results show that the gene cassettes in integrons may cause resistance to antibiotics in Pseudomonas aeruginosa. The dfr and aadB gene cassettes were positive in 7 isolates. samples had both the gene cassette were resistant to gentamicin, and trimethoprim(100%). And 6 isolates (85%) were resistant to ampicillin and cefotaxime. 5 (71%) isolates were resistant to Cefepime and imipenem. The horizontal transfer of antibiotic resistance , involved integrons. Multi-gene cassette is often carried by mobile genetic elements and led to the spread of resistance from one end to the other. By PCR technique that high sensitivity and specificity can be good diagnostic method . So appropriate antibiotics to control the infection could suggest then.