Bacteriological Spectrum and Antimicrobial Susceptibility Patterns of Uropathogens Isolated from Patients with Urinary Tract Infections in a Tertiary Care Hospital

Background: Urinary tract infections (UTIs) are one of the most frequently occurring bacterial infections in community and hospital environments and are a major cause of morbidity in the world. UTIs are becoming more difficult to treat, as multidrug-resistant organisms have become increasingly common. Bacteriological profile and antimicrobial susceptibility testing has to be done on an ongoing basis to inform empirical treatment and prevent the development of resistant bacteria. Material and Methods: This observational study was conducted in the Microbiology Laboratory of a tertiary care hospital between 2024-2025.A total of 300 urine samples were collected from hospitalized patients with suspected urinary tract infections. Urine samples were processed using standard microbiological techniques, and significant bacteriuria was determined according to the Kass criteria. Identification of isolates was carried out using conventional biochemical methods. Antimicrobial susceptibility testing was performed using the Kirby–Bauer disk diffusion method in accordance with Clinical and Laboratory Standards Institute (CLSI) guidelines. Results: Out of 300 urine samples, 93 (31%) showed significant bacteriuria. The highest number of culture-positive cases was observed in the 20–40 years age group (39.8%). Escherichia coli was the predominant isolate (50.5%), followed by Klebsiella pneumoniae (20.4%), Enterococcus spp. (11.8%), Pseudomonas spp. (8.6%), Acinetobacter spp. (5.4%), and Staphylococcus aureus (3.2%). Among Gram-negative isolates, Colistin and Polymyxin B showed 100% susceptibility, followed by Meropenem and Imipenem, while lower susceptibility was observed with cephalosporins and fluoroquinolones. Gram-positive isolates demonstrated high susceptibility to Vancomycin and Linezolid. Conclusion: Escherichia coli remains the most common uropathogens in urinary tract infections. The study highlights increasing resistance to commonly used antibiotics and emphasizes the need for continuous surveillance of antimicrobial susceptibility patterns and implementation of antimicrobial stewardship programs to ensure effective management of urinary tract infections.

Keywords: Urinary tract infection; Uropathogens; Antimicrobial susceptibility; Escherichia coli; Multidrug resistance; Kirby–Bauer method.