Prevalence and Antimicrobial Resistance Pattern of Carbapenem-Resistant Non- Fermenting Gram-Negative Bacilli from Clinical Isolates in a Tertiary Care Hospital in Nepal

Background: Carbapenem-resistant non-fermenting Gram-negative bacilli (NFGNB), particularly Pseudomonas aeruginosa and Acinetobacter baumannii , have emerged as significant pathogens in hospital-acquired infections due to their multidrug-resistant nature. Carbapenems, previously considered last-resort antibiotics, are now increasingly ineffective due to the widespread emergence of carbapenemase-producing strains. This resistance not only limits therapeutic options but also contributes to increased morbidity, mortality, and healthcare costs. This study was conducted to determine the prevalence and resistance patterns of carbapenem-resistant NFGNB in various clinical samples at a tertiary care hospital. Methodology: A hospital-based cross-sectional study was conducted at Dhulikhel Hospital, Kathmandu University Hospital, from March 2024 to April 2025. Clinical specimens including sputum, pus, urine, and other body fluids were collected and processed using standard microbiological techniques. Identification of NFGNB was performed using conventional biochemical tests. Antimicrobial susceptibility testing (AST) was carried out using the Kirby-Bauer disk diffusion method and interpreted according to CLSI guidelines. Results: Out of 6,958 culture-positive samples, 709 (10.1%) were identified as NFGNB. These included Acinetobacter species (n=265; 37.37%), Pseudomonas aeruginosa (n=438; 61.77%), Burkholderia cepacia complex (n=3; 0.42%), and others (n=3; 0.42%). Carbapenem resistance was observed in 34.33% of Acinetobacter spp., 15.06% of Pseudomonas aeruginosa , and 66.66% of Burkholderia cepacia complex isolates. Conclusion: Among NFGNB, carbapenem resistance was most prevalent in Acinetobacter species. The high resistance rate emphasizes the urgent need for antimicrobial stewardship, rigorous infection control practices, and continuous surveillance to prevent further spread of these multidrug-resistant organisms in healthcare settings.