Evaluation of Resistance Dynamics in Pseudomonas aeruginosa Isolated From ICUs of a Tertiary-Level Hospital in Eastern India: A Five-Year Study

Background <i>Pseudomonas aeruginosa</i>, an important nosocomial bacterial pathogen, poses serious healthcare challenges, particularly in ICUs, leading to morbidity and mortality. Moreover, the emergence of multidrug-resistant (MDR), difficult-to-treat resistant (DTR), and extensive drug-resistant (XDR) isolates has resulted in very limited treatment options. Limited data are available on the antibiotic susceptibility patterns of <i>P. aeruginosa</i> in eastern India during the study period. This study aimed to generate insights into the resistance profile of <i>P. aeruginosa</i> over a five-year period. Materials and methods This retrospective study was conducted from 2021 to 2025 in a tertiary care hospital in Bhubaneswar, India. Samples from ICU patients, including respiratory samples, blood, pus, urine, tissue, and swabs, were cultured on appropriate media. Bacterial identification and antimicrobial susceptibility testing (AST) were performed using the VITEK 2 Compact system (bioMérieux, Marcy-l'Étoile, France). Results were interpreted according to the Clinical & Laboratory Standards Institute (CLSI) 2025 guidelines. All data, including occurrence, antibiogram, comorbidities, and patient predisposing factors, were retrieved from the hospital's laboratory information system. Results A total of 988 <i>P. aeruginosa</i> isolates were identified, representing a prevalence rate of 12.08% (988/8174). The highest occurrence was observed in adult ICUs (96.26%, 951/988), followed by pediatric ICUs (3.24%, 32/988) and neonatal ICUs (0.5%, 5/988). Prevalence was higher in males (67%, 659/988) than in females (33%, 329/988). Overall AST patterns revealed the highest susceptibility to amikacin (56%, 523/942), followed by cefepime (53%, 471/891). Resistance was highest for piperacillin/tazobactam (53%, 473/891), followed by imipenem (51%, 446/884) and meropenem (50%, 467/943). Trend analysis showed a decline in resistance to piperacillin/tazobactam, meropenem, imipenem, ciprofloxacin, and levofloxacin over the 2021-2025 period. Conclusions This study demonstrates the presence of MDR, non-MDR, DTR, and XDR strains of <i>P. aeruginosa</i> in ICUs, with periodic fluctuations in prevalence. This is concerning, as ICU patients are critically ill and infections caused by drug-resistant pathogens may have severe consequences. Continuous antimicrobial stewardship, strict infection control practices, and active surveillance are essential to prevent further escalation of resistance.