Abstract
Hospital-acquired infections caused by P. aeruginosa contribute to global distress because of the elevated rates of microbial antibiotic resistance. Aminoglycosides are antipseudomonal agents that are effectively and frequently utilized to eradicate this infection. This current study is a retrospective study investigating plasmid-mediated aminoglycoside resistance by focusing on the prevalence of the genes encoding aminoglycoside-modifying enzymes (AMEs) and 16S rRNA methylase among P. aeruginosa clinical isolates from Taif, Saudi Arabia. A hundred clinical isolates of P. aeruginosa were collected. The isolates were identified from February 2021 to February 2022. Antibiotic susceptibility testing and MICs were determined using (DD) and (BM-MIC) testing, respectively. AMEs and 16S rRNA methylase variants in bacterial isolates were amplified via PCR for genetic detection. A relatively high multiple antibiotic resistance rate corresponding to 10-32% was reported. Eighteen percent of P. aeruginosa isolates were gentamicin-amikacin-tobramycin resistant according to the MIC levels. The aminoglycoside-resistant strains were additionally identified via GyrA gene sequencing. The phylogenic relatedness dendrogram of the sequenced GyrA genes was performed using a neighbor-joining method via MEGAX software version 10.2.6. The most prevalent AME encoding gene was aac(6')-Ib, observed in 94.4% of resistant isolates, while a resistance gene cocktail of [aac(6')-Ib and ant(3″)-I] was a highly frequent combination (27.8%). This study updated the knowledge about aminoglycoside resistance mechanisms in P. aeruginosa, which constitutes an urgent need, especially after the COVID-19 crisis, which was associated with increased antimicrobial use and resistance rates.