Characterization of Integron Genes of Clinical Isolates of Pseudomonas aeruginosa which Perform Resistance to Antibiotics and Biofilm Formation by these Strains


  • A.F. Alfarras Institute of Genetic Engineering and Biotechnology for Postgraduate Studies, University of Baghdad, Iraq
  • W.A. Al-Daraghi Institute of Genetic Engineering and Biotechnology for Postgraduate Studies, University of Baghdad, Iraq



integron, antibiotic resistance, Pseudomonas aeruginosa, biofilm


Pseudomonas aeruginosa is a bacterium that holds significant clinical and epidemiological significance. It serves as the principal etiological cause of opportunistic infections in individuals with impaired immune systems. Integrons are known to have a notable impact on Gram-negative bacteria, particularly in the context of P. aeruginosa, a bacterium recognized for its ability to develop resistance to antimicrobial drugs. Aim. To systematically characterize and detect integron genes (intI, intII, intIII) with antibiotic-resistant and biofilm-forming capabilities in isolated P. aeruginosa. Methods. A total of 209 samples were collected from Al Yarmouk Teaching Hospital in Baghdad City, Iraq to isolate P. aeruginosa. The process of bacterial identification was carried out phenotypically and by biochemical tests. Antibiotic susceptibility was measured using the Vitek2 system. Biofilm quantification was done by the microtiter method. The PCR approach was employed to assess the presence of class 1, 2, and 3 integrons. Results. P. aeruginosa was identified in 83 isolates by using a combination of morphological and biochemical examinations where all isolates showed the ability to grow a selective medium on cetrimide agar for P. aeruginosa. The results also showed significant variances (p < 0.05) among the percentage of a number of samples and isolated P. aeruginosa. The burn and wound infection scored the highest percentages (25% and 19%) based on the positivity of P. aeruginosa, whereas burn and ear sites scored the highest percentage (58% and 50%). Also, the isolates show the ability to form biofilm at a percentage of 68.7% with resistance to a high number of antibiotics. The multidrug-resistant and sensitive P. aeruginosa isolates scored high percentages (49.4% and 34.9%) whereas potentially pan drug-resistant and extensively drug-resistant isolates scored low percentages (2.4% and 13.3%). PCR results showed that integron I scored the highest percentage (100%) compared to integron 2 found in 3 (10%) isolates, and no intI3 gene was detected in any of the P. aeruginosa isolates. Conclusions. Overall, the findings of the present investigation indicate that integrons and biofilm development are recognized as significant factors contributing to antibiotic resistance in P. aeruginosa. The prevalence of class 1 integrons is shown to be significantly high in all bacterial isolates, with a complete occurrence rate of 100%. This high incidence of class 1 integrons is associated with the development of resistance to crucial antibiotics, including β-lactams, aminoglycosides, and cephalosporins.


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How to Cite

Alfarras, A., & Al-Daraghi, W. (2024). Characterization of Integron Genes of Clinical Isolates of Pseudomonas aeruginosa which Perform Resistance to Antibiotics and Biofilm Formation by these Strains. Mikrobiolohichnyi Zhurnal, 86(1), 3-13.