Investigation of virulence genes in P. aeruginosa strains isolated from clinical samples

Pseudomonas aeruginosa has a wide range of virulence factors, metabolic flexibility and resistance to multiple antibiotics, making it difficult to treat hospital-acquired infections in particular. In this study, virulence genes were investigated in P. aeruginosa strains isolated from patient samples sent from various clinics to Van YYU Dursun Odabas Medical Center Microbiology Laboratory. In this study, 11 virulence genes were investigated in 100 P. aeruginosa strains isolated from clinical samples. Clinical samples were cultured on sheep blood agar and eosin methylene blue agar media and incubated at 37 for 24-48 hours. At the end of this period, gram negative, oxidase and catalase test positive sour grape odor samples with appropriate colony morphology were evaluated as Pseudomonas. These isolates were then identified and tested for antibiotic susceptibility using the BD Phoenix™ (Becton Dickinson, USA) automated system. The strains included in the study were stored in sterile beaded tubes at -80 for the detection of virulence genes. HY-BAGDNA-100 (Turkey) Bacterial Genomic DNA Isolation Kit was used for Bacterial Genomic DNA Isolation. Las R, Las I, LasA, LasB, Rhl I, Rhl R, Alg D, Exo S, Exo U, Exo T and Exo Y genes in P. aeruginosa strains were investigated using appropriate primers using the Polymerase Chain Reaction (PCR) method. 22% of the samples were respiratory secretions, 14% urine, 20% sputum, 11% wound, 8% blood and 25% other sterile body fluids. Of the strains included in the study, 65 (65%) were isolated from male and 35 (35%) were isolated from female patients. 92 (92%) of the strains were obtained from adult and 8 (8%) from pediatric patients. 41 (41%) of the samples belonged to patients from intensive care units and 59 (59%) belonged to patients from wards. In antibiotic susceptibility tests, resistance was detected at 87.8 % to ceftazidime/avibactam, 60.6 % to ciprofloxacin, 58.7% to levofloxacin and 54.4% to ceftazidime. Colistin and tobramycin were the antibiotics with the lowest resistance rates with 17.3 % and 12.5%, respectively. The detection rates of virulence genes, in order of frequency, are as follows; Las B 100%, Las I 98%, Alg D 98%, Las R 97%, Exo T 97%, Rhl R 92%, Exo Y 90%, Las A 54%, Exo U 53%, Rhl I 41% and Exo S 37% were detected. The fact that these genes are so common indicates that these strains have high pathogenicity potential. The results obtained show that P. aeruginosa strains in our region both carry high levels of virulence factors and have developed multiple antibiotic resistance. These findings reveal that infection control measures should be strengthened and treatment protocols should be updated according to local resistance patterns.