Molecular investigation of secretion systems among Pseudomonas aeruginosa clinical isolates in Baquba, Iraq

Background: Pseudomonas aeruginosa is one of the most adaptable bacterial kinds that has ability of surviving in severe environmental circumstances. It works as a distinct example of an opportunistic pathogen, frequently exploiting immunocompromised individuals to establish infection. Particularly, it ranks as the second most widespread opportunistic pathogen and remains a leading cause of hospital-acquired infections. secretion systems are protein structures located on P. aeruginosa cell membranes that had important role for transporting molecules which are related with pathogenesis out of the cell and into the environment or directly into other cells. Aim of study: This study goals to detection of several secretion systems (Type I, Type II, Type III, Type V, and Type VI) by the associated genes with outer membrane channels (AprF, HasF, XcpQ, HXCQ, pscC, CdrB, cupB3, hcp, and TatA) using PCR. Methods: An entire of 390 clinical samples had been collected between the periods from 15 September 2025 to 20 January 2025. Samples had got from Baquba Teaching Hospital and various consulting clinics in Diyala Province. Patients presented with varied infections and inflammatory conditions, with urinary tract infections, otitis media, sputum, burns, wounds, and bacteremia. "Antibiotic susceptibility of the isolates ad evaluated via the disk diffusion method (Bauer-Kirby) on Mueller-Hinton agar. Genomic DNA was extracted via the boiling method, then Specific primers were used to detect the genes under study by PCR. Results: Fifty-five isolates (14%) had recognized as Pseudomonas aeruginosa. The identification has based on microscopic examination, cultural characteristics, and biochemical tests. Its percentage in otitis media swabs, burn swabs, sputum swabs, wound swabs, urinary tract infections and bacteremia cases (5%, 2.5%, 2%, 1.7%, 1.5% and 1%) respectively. The bacterial isolates under study showed varying resistance to the following antibiotics: TTC, CFM, ATM, LEV, IMI, PRL, NOR, MRP, TOB and PTZ were 98.18%, 78.18, 34.55%, 32.73%, 30.91%, 27.27%, 23.63%, 21.82%, 21.82% and 18.18% respectively. Polymerase chain reaction (PCR) analysis revealed the presence of genes associated with the secretion systems under study includes TatA, AprF, HasF, XcpQ, HXCQ, pscC, CdrB, CupB3 and hcp were 100%, 100%, 37.5%,87.5%, 100%, 100%, 100%, 83.33% 100%. Conclusion: The whole isolates inspected in this study own expresses genes responsible for the creation of outer membrane channels which confirming the presence of complete secretion systems (Type I, Type II, Type III, Type V, and Type VI). This indicates their ability to secrete virulence-associated proteins, adapt to hostile environments, and show or display high pathogenic potential. Furthermore, these features contribute to their resistance to antibiotics and evasion of host immune defenses.