Antimicrobial resistance patterns and clinical outcomes in critically ill patients.

Original Article

Abstract

Objective: To determine the antimicrobial resistance patterns among bacterial pathogens isolated from critically ill patients and evaluate their association with clinical outcomes.

Methodology: This longitudinal observational study was conducted in the Department of Medicine, Karachi Teaching Hospital, from October 2025 to March 2026. We enrolled 300 critically ill patients admitted to the ICU. We recorded demographic characteristics, comorbidities, previous antibiotic exposure, isolated organisms, antimicrobial susceptibility patterns, multidrug resistance, mechanical ventilation, ICU stay, treatment response, and mortality.

Results: We identified bacterial infection in most clinically suspected cases. The most common bacteria isolated were Acinetobacter baumannii, 78 (26.0%), followed by Klebsiella pneumoniae, 67 (22.3%), Pseudomonas aeruginosa, 49 (16.3%), E. coli, 42(14.0%), S. aureus, 31 (10.6%), and Enterococcus spp 15(5.0) respectively. Multidrug-resistant organisms constituted a substantial proportion of isolates. Patients with resistant infections had higher mortality, longer ICU stays, and more frequent mechanical ventilation than patients with susceptible infections.

Conclusion: Our study concluded that antimicrobial resistance is a significant issue among critically ill patients and is related to unfavorable clinical outcomes. Consistent ICU-specific antimicrobial surveillance, right empirical treatment, culture-directed treatment, infection-prevention procedures, and antimicrobial stewardship are mandatory to lessen the burden of resistant infections.

Critically ill patients, Antimicrobial resistance; MDR, Clinical outcomes.