Antimicrobial Resistance Pattern of Pseudomonas aeruginosa Isolates from Tertiary Care Hospitals in Kathmandu.

Background Antimicrobial resistance, caused by Pseudomonas aeruginosa (P. aeruginosa), poses a global health threat, limiting treatment options and increasing morbidity and mortality rates due to its intrinsic and multidrug resistance. Objective To determine the antimicrobial resistance patterns of P. aeruginosa isolates from patients visiting or admitted to tertiary care hospitals in Kathmandu. Method A cross-sectional study was conducted at Bir Hospital and Tribhuvan University Teaching Hospital (TUTH) from December 2021 to December 2022. Isolates were identified and tested for antibiotic susceptibility following standard microbiological guidelines. Result The antimicrobial resistance of 200 P. aeruginosa isolates increased from low to high levels, as per the recommended anti-pseudomonal antibiotics by the Clinical and Laboratory Standards Institute (CLSI), from 0% to 94%. piperacillin/tazobactam exhibited significantly lower resistance at 18(9%) and while considerably higher resistance was observed with ceftazidime at 188(94%) compared to different antibiotics, followed by amikacin 34(17%), imipenem 58(29%), ciprofloxacin 42(21%), aztreonam 51(25.5%), and fosfomycin 44(22%). No resistance was observed to colistin and polymyxin B. P. aeruginosa resistant to carbapenem was accounted for 33.5% of the total, and multidrug resistance categories included multidrug resistance (MDR) at 39.0%, extensively drug resistance (XDR) at 13.5%, and P. aeruginosa difficult-to-treat (DTR PA) at 4.6%. Conclusion Most of the isolates were resistant to anti-pseudomonal antibiotics; however, colistin, polymyxin B, amikacin, doripenem, piperacillin/tazobactam, and fosfomycin were effective against MDR P. aeruginosa. Regular surveillance measures are essential to manage antimicrobial resistance.