Bacteriological and antimicrobial susceptibility profile of multidrug-resistant gram-negative blood stream infections in a tertiary care hospital, Uttarakhand.

Abstract

Background: Gram-negative bloodstream infections are an important cause of morbidity among hospitalized patients, and multidrug resistance (MDR) can significantly limit treatment options. Local surveillance of causative organisms and antimicrobial susceptibility patterns is essential for appropriate empirical therapy and antimicrobial stewardship. This study evaluated the bacteriological profile and antimicrobial susceptibility patterns of Gram-negative bloodstream isolates, with emphasis on MDR, in a tertiary care hospital in Uttarakhand. Objective: To determine the bacteriological profile and antimicrobial susceptibility patterns of Gram-negative bloodstream isolates, particularly MDR isolates. Methods: A prospective cross-sectional study was conducted in the Department of Microbiology over six months, from December 2025 to May 2026. Blood culture records yielding Gram-negative bacilli were reviewed, and organism-specific antimicrobial susceptibility data were analyzed. Duplicate entries with the same laboratory accession number were removed. MDR was defined as resistance to at least one antimicrobial agent in three or more antimicrobial classes. Results: After data cleaning, 276 Gram-negative bloodstream isolates were identified. Escherichia coli was the most frequently isolated organism (98/276, 35.5%), followed by Klebsiella pneumoniae (58/276, 21.0%), Acinetobacter baumannii complex (34/276, 12.3%), and Pseudomonas aeruginosa (18/276, 6.5%). MDR was observed in 65.3% of E. coli, 72.4% of K. pneumoniae, 82.3% of A. baumannii complex, and 33.3% of P. aeruginosa. Imipenem resistance was highest in A. baumannii complex (82.3%) and K. pneumoniae (69.0%). Meropenem resistance showed a similar pattern. Conclusion: The study demonstrated a considerable burden of MDR among Gram-negative bloodstream isolates, particularly A. baumannii complex and K. pneumoniae. Continued local surveillance and organism-specific susceptibility data are important for guiding empirical antibiotic therapy and antimicrobial stewardship.