Microbiological Profile of Klebsiella pneumoniae in Intensive Care Units: A Cross-Sectional Study

Abstract

Background: Patients in intensive care units (ICUs) are highly susceptible to severe infections due to critical illness and invasive interventions. Klebsiella pneumoniae has emerged as a major nosocomial pathogen with increasing antimicrobial resistance, contributing to substantial morbidity and mortality. Aim: To determine the distribution of Klebsiella pneumoniae in ICUs and assess carbapenemase production and colistin susceptibility among the isolates. Methods: This hospital-based retrospective observational study was conducted over 6 months, from August 2025 to January 2026, in the ICUs of a tertiary care hospital. A total of 225 K. pneumoniae isolates recovered from clinical samples were included. Identification was performed using standard microbiological methods. Antimicrobial susceptibility testing was performed using the modified Kirby–Bauer disk diffusion and broth microdilution methods, in accordance with the guidelines of the Clinical and Laboratory Standards Institute (CLSI). Carbapenemase production was detected using phenotypic methods, and colistin susceptibility was determined by broth microdilution. Isolates were classified as multidrug-resistant (MDR), extensively drug-resistant (XDR), or pan-drug-resistant (PDR). Results: The majority of isolates were recovered from the MICU (46.7%) and NICU (36.0%). Blood (50.22%) and respiratory samples (28.89%) were the most common sources. High resistance rates were observed to cephalosporins (>93%), ciprofloxacin (91.56%), aminoglycosides (75–82%), and carbapenems (73–75%). Resistance to colistin was minimal (1.33%). Carbapenemase production was detected in 37.5% of the isolates, with metallo-β-lactamase being the predominant type. XDR isolates were the most common (60.45%), followed by MDR isolates (29.33%), while PDR isolates were relatively few (1.33%). Conclusion: A high burden of XDR K. pneumoniae, along with substantial carbapenem resistance, was observed in the ICUs. Colistin remained highly active against the isolates. Strengthening antimicrobial stewardship, infection prevention and control measures, and surveillance is essential to curb the emergence and spread of antimicrobial resistance. Key words: Klebsiella pneumoniae; Intensive Care Unit (ICU); Antimicrobial resistance (AMR); Carbapenemase production; Colistin susceptibility.