International Journal of Multidisciplinary Health Sciences and Research

Category: Original Article,      DOI: N/A Recived: 03/03/2025, Accepted: 21/03/2025, Published online: 30/03/2025

Prevalence of Extended-Spectrum Beta-Lactamase Producing Gram-Negative Organisms in Clinical Isolates at a Tertiary Care Teaching Hospital: A Prospective Observational Study

Desh Nidhi Singh¹*, Yogendra Singh²

Background and Objectives: Extended-spectrum beta-lactamase (ESBL) producing gram-negative organisms are an escalating clinical challenge in healthcare settings worldwide, rendering most beta-lactam antibiotics ineffective and significantly restricting treatment options. Their rapid dissemination through plasmid-mediated horizontal gene transfer, compounded by high antibiotic consumption and weak stewardship in tertiary care environments across South Asia, makes institutional surveillance an urgent necessity. This study aimed to determine the prevalence of ESBL-producing gram-negative organisms among clinical isolates at a tertiary care teaching hospital, identify the predominant bacterial species, and evaluate their antibiotic susceptibility profiles. Methods: A prospective observational study was conducted over nine months (March 2024 to November 2024) at a tertiary care teaching hospital. A total of 140 non-duplicate gram-negative isolates from clinical specimens, including urine, pus, blood, sputum, and other body fluids, were included. ESBL detection was performed using the combined disc test and modified double disc synergy test (DDST) per CLSI 2024 guidelines. Antibiotic susceptibility testing was performed using the Kirby-Bauer disc diffusion method. Data were analyzed using SPSS version 23.0 with descriptive statistics and chi-square tests. Results: Of 140 gram-negative isolates, 58 (41.4%) were confirmed ESBL producers. Escherichia coli (48.6%) and Klebsiella pneumoniae (25.0%) were the predominant organisms. ESBL positivity was highest in K. pneumoniae at 51.4%, followed by E. coli at 47.1%. Urine specimens constituted the largest proportion of isolates at 46.4%, and the intensive care unit accounted for the highest proportion of ESBL isolates at 31.0%. Carbapenems retained the strongest activity, with imipenem sensitivity at 96.6%. Resistance to cotrimoxazole (72.4%), ciprofloxacin (67.2%), cefotaxime (91.4%), and ceftazidime (87.9%) was markedly high. Conclusions: This study documented a high prevalence of ESBL-producing organisms with significant co-resistance across multiple antibiotic classes. These findings underscore the urgent need for routine ESBL screening, evidence-based antibiotic stewardship, and strengthened infection control measures at the institutional level.