Antimicrobial Resistance Pattern of Bacterial Isolates from ICU Patients in a Tertiary Care Hospital

Objective: To determine the frequency and antimicrobial resistance (AMR) pattern of bacterial isolates among intensive care unit (ICU) patients in a tertiary care hospital. Methodology: This cross-sectional descriptive study was carried out in the Microbiology Laboratory of Provincial Headquarter Hospital, Gilgit, from October 2025 to March 2026 after ethical approval. After taking informed consent, 150 culture specimens received from ICU patients were tested by non-probability consecutive sampling. Each specimen was inoculated onto the appropriate culture media, then incubated and carefully identified based on colony morphology, Gram stain, and biochemical tests. The antimicrobial sensitivity testing (AST) was performed by the Kirby-Bauer disc diffusion method. The antibiotic zone diameters were reported following the Clinical and Laboratory Standards Institute (CLSI) guidelines 2025. The statistical analysis was done by the Statistical Package for the Social Sciences (SPSS) version 27. Results: The most common pathogen isolated was Staphylococcus (31.6%), succeeded by Escherichia coli (17.3%), Klebsiella pneumoniae (15.3%), Pseudomonas aeruginosa (13.3%), Acinetobacter baumannii (10.2%), Enterococcus species (9.2%), and Proteus species (3.1%). Staphylococcus aureus, Coagulase-negative Staphylococcus species (CoNS) and Enterococcus species were sensitive to vancomycin and linezolid. Staphylococcus aureus and CoNS showed less resistance to gentamicin (35.7% versus 23.5%) and doxycycline (28.6% and 17.6%). Carbapenems showed 100% susceptibility in all Gram-negative isolates. Piperacillin-tazobactam, amikacin and nitrofurantoin showed better sensitivities as compared to other antibiotics. Escherichia coli, Klebsiella pneumoniae, Proteus and Pseudomonas showed 29.4%, 33.3%, 0% & 38.5% resistance to piperacillin-tazobactam and 17.6%, 20%, 33.3% & 46.1% to amikacin. Resistance to nitrofurantoin was 27.3% for E. coli, 0% for Klebsiella pneumoniae, and Proteus species. Acinetobacter baumannii exhibited higher antibiotic resistance. Conclusion: Gram-negative bacteria constituted 59.2%, whereas Gram-positive bacteria made up 40.8% of the isolates. Around 71.4% isolates of Staphylococcus aureus were methicillin-resistant and 70.6% Escherichia coli & 73.3% Klebsiella pneumoniae were extended-spectrum beta-lactamase (ESBL) producers. A higher antimicrobial resistance was seen in the isolates.