Assessment of Antibiotic Usage Patterns and Antimicrobial Resistance Profiles in Emergency Department Infections: A Cross-Sectional Study

Abstract

Background: Antimicrobial resistance (AMR) is a critical global concern, with emergency departments (EDs) being high-risk environments for empirical antibiotic overuse. Understanding prescribing trends and their link to resistance is essential for strengthening antimicrobial stewardship practices.

Aim: To assess the antibiotic usage patterns and antimicrobial resistance profiles among patients with infections presenting to the emergency department.

Methods: A hospital-based cross-sectional study was conducted among 200 adult patients with suspected or confirmed infections presenting to the ED over one year. Data on demographics, clinical profile, antibiotic prescriptions, and microbiological findings were collected. Antimicrobial susceptibility testing was performed using standard CLSI protocols. Statistical analysis included descriptive summaries, z-tests for differences in proportions and means, and odds ratio estimation for exposure-resistance associations.

Results: Of 200 patients, 127 (63.5%) were culture-positive. Prior antibiotic exposure within 90 days was significantly associated with culture positivity (29.9% vs. 16.4%; p=0.034). Healthcare-associated isolates exhibited higher resistance rates to piperacillin-tazobactam (39.5% vs. 22.6%; p=0.045) and carbapenems (25.6% vs. 10.7%; p=0.029). Extended-spectrum β-lactamase production among Enterobacterales was significantly higher in healthcare-associated infections (67.7% vs. 45.2%; p=0.040). Guideline-concordant empirical therapy was associated with fewer multidrug-resistant isolates (OR=0.41; 95% CI 0.19-0.91; p=0.028) and lower 7-day revisit rates (8.0% vs. 21.0%; p=0.0089).

Conclusion: The study demonstrates that inappropriate or non-guideline-based antibiotic prescribing, prior exposure, and healthcare-associated settings contribute to higher resistance rates. Strengthening empirical therapy guidelines, timely de-escalation, and regular AMR surveillance in the ED can significantly improve infection outcomes and mitigate resistance trends.