Clinical associations and prevalence of extended-spectrum beta-lactamase and AmpC-producing Enterobacterale s: A cross-sectional study
Shefali Garg, Anuradha Malhotra, Loveena Oberoi, Sapna Batra, Kamaldeep Singh, Deepshikha MangatObjectives:
The rise of extended-spectrum beta-lactamase (ESBL) and AmpC beta-lactamase enzymes among Enterobacterales significantly limits therapeutic options in healthcare settings. Local surveillance is critical to guide empirical therapy. This study aimed to determine the prevalence, co-production, and clinical risk factors of ESBL and AmpC-producing Enterobacterales in a tertiary care hospital in Amritsar.
Material and Methods:
A prospective, laboratory-based surveillance study was conducted from January 2023 to June 2024. Clinical isolates of Enterobacterales ( n = 200) demonstrating resistance to third-generation cephalosporins (ceftazidime or cefotaxime) during routine antimicrobial susceptibility testing were evaluated. Phenotypic confirmation of ESBL production was performed using the Clinical and Laboratory Standards Institute combination disk method. AmpC enzyme production was determined via the cefoxitin-cloxacillin double-disk synergy test.
Statistical analysis:
Data were analyzed with IBM Statistical Package for the Social Sciences version 20, using frequency tables, Chi-square tests, and descriptive statistics, with significance set at p ≤ 0.05.
Results:
Among the 200 cephalosporin-resistant Enterobacterales strains evaluated, ESBL production was phenotypically confirmed in 160 isolates (80%), AmpC beta-lactamase was detected in 77 isolates (38.5%), while co-production of both was observed in 72 strains. A history of invasive devices or clinical procedures was significantly associated with both ESBL, AmpC, and ESBL-AmpC co-production ( p = 0.013, 0.005, and 0.002, respectively). The remaining 38 screening-positive, unconfirmed strains likely represent alternative, nonenzymatic resistance mechanisms such as outer membrane porin loss or efflux pump upregulation.
Conclusions:
This study demonstrates a high institutional prevalence of ESBL and AmpC co-production among clinical Enterobacterales isolates, strongly associated with invasive procedures. In resource-limited settings lacking molecular diagnostics, routine phenotypic screening using simple, cost-effective methods is essential to optimize clinical treatment and antimicrobial stewardship