Analysis of Gene Expression Linked to Efflux Pumps and Porins in Pseudomonas aeruginosa Isolates

Background: Efflux pumps (EPs) are essential in bacterial resistance, actively expelling antibiotics to reduce susceptibility. In Pseudomonas aeruginosa , they show a role in multi-drug resistance. Porin modifications, are serious for carbapenem uptake, and enhance resistance by restricting antibiotic entry. Objective: This study investigates the roles of efflux pumps and porins in antibiotic resistance, aiming to guide more effective treatment strategies for Pseudomonas aeruginosa infections. Materials and Methods: A total of 300 clinical specimens were collected from Hilla Teaching Hospitals between January and June 2024, comprising wounds (40%), burns (40%), blood (12%), and urine (8%). Bacteria were cultured, identified through Gram staining and biochemical tests, and confirmed as Pseudomonas aeruginosa (8.33%) via the Vitek-2 system. Antimicrobial susceptibility testing was conducted for 16 antibiotics. Efflux pump genes (adeB, adeJ) were detected using PCR, and their expression was quantified through RT-qPCR. Results: Pseudomonas aeruginosa isolates showed high resistance to β-lactams, carbapenems, and aminoglycosides, with colistin remaining effective. The adeB gene was present in all isolates, while adeJ was absent. Overexpression of OperD (80%) and adeB (44%) was observed, alongside complete downregulation of the CarO gene (100%). Conclusion: This study identified Pseudomonas aeruginosa in 8.33% of clinical specimens, revealing key resistance mechanisms, including OperD and adeB overexpression and CarO downregulation.