Prevalence of ESBL-Producing Gram-Negative Uropathogens and Their Antimicrobial Susceptibility Patterns in Urinary Tract Infections at a Tertiary Care Hospital in South India

Pavithra D.P, Vijay Kumar Gangannagari, Ravikant
Author(s)
1Associate Professor, Department of Microbiology, Dr. B.R. Ambedkar Medical College, Bangalore, Karnataka, India. 2Assistant Professor, Department of Microbiology, Siddaganga Medical College and Research institute, Tumakuru, Karnataka, India. 3Associate Professor, Department of Microbiology, Maharishi Markandeshwar Institute of Medical Science and Research, Maharishi Markandeshwar (Deemed to be University), Mullana-Ambala, Haryana, India

Abstract

Background: Urinary tract infections caused by extended-spectrum beta-lactamase (ESBL)-producing uropathogens pose a significant therapeutic challenge due to increasing antimicrobial resistance. This study aimed to determine the prevalence of ESBL-producing uropathogens and their antimicrobial susceptibility patterns among UTI patients at a tertiary care hospital in South India. Material and Methods: A prospective cross-sectional study was conducted over one year. Of 420 urine samples collected from clinically suspected UTI patients, 384 were eligible for final analysis after excluding contaminated and duplicate samples. Significant bacteriuria was defined as ≥10⁵ CFU/mL. Uropathogens were identified by standard microbiological methods and antimicrobial susceptibility testing was performed by Kirby-Bauer disk diffusion following CLSI guidelines. ESBL production was confirmed by the Combined Disc Test. Results: Of 384 eligible samples, 168 (43.7%) showed significant bacteriuria. Female patients predominated (68.2%). Escherichia coli was the most common isolate (57.1%), followed by Klebsiella pneumoniae (21.4%). Among 148 Gram-negative isolates, 68 (45.9%) were confirmed ESBL producers. Near-universal resistance to third-generation cephalosporins (94–97%) and high fluoroquinolone resistance (79.4%) was observed among ESBL producers. Amikacin (91.2%) and imipenem (98.5%) retained excellent activity. Prior antibiotic use and previous hospitalization were independent risk factors for ESBL acquisition. Conclusion: A high prevalence of ESBL-producing uropathogens with resistance to commonly used empiric antibiotics was observed. Routine ESBL screening, culture-guided therapy, and antibiotic stewardship programs are strongly recommended to contain antimicrobial resistance in this region.

Keywords: Extended-spectrum beta-lactamase; uropathogens; urinary tract infection; antimicrobial resistance; antibiotic stewardship; South India.

Outline