ABSTRACT
BACKGROUND: One of the most prevalent bacteria that cause nosocomial infections is Pseudomonas aeruginosa. Fluoroquinolones (FQ) and aminoglycosides are vital antipseudomonal drugs, but resistance is increasingly prevalent. The study sought to investigate the diverse mechanisms underlying FQ and aminoglycoside resistance in various P. aeruginosa strains particularly during the COVID-19 crisis. METHODS: From various clinical and environmental samples, 110 P. aeruginosa isolates were identified and their susceptibility to several antibiotic classes was evaluated. Molecular techniques were used to track target gene mutations, the presence of genes encoding for quinolone resistance, modifying enzymes for aminoglycosides and resistance methyltransferase (RMT). Efflux pump role was assessed phenotypically and genotypically. Random amplified polymorphic DNA (RAPD) analysis was used to measure clonal diversity. RESULTS: QnrS was the most frequently encountered quinolone resistance gene (37.5%) followed by qnrA (31.2%) and qnrD (25%). Among aminoglycoside resistant isolates, 94.1% harbored modifying enzymes genes, while RMT genes were found in 55.9% of isolates. The aac(6')-Ib and rmtB were the most prevalent genes (79.4% and 32.3%, respectively). Most FQ resistant isolates overexpressed mexA (87.5%). RAPD fingerprinting showed 63.2% polymorphism. CONCLUSIONS: Aminoglycosides and FQ resistance observed in this study was attributed to several mechanisms with the potential for cross-contamination existence so, strict infection control practices are crucial.