Patterns of antibiotic resistance in community-acquired infections: a study from a tertiary care hospital

Abstract

Background: Antibiotic resistance in community-acquired infections (CAIs) has emerged as a growing global concern with serious clinical and public health implications. Rising resistance to first-line therapies is reducing treatment effectiveness, increasing healthcare costs, and contributing to higher morbidity and mortality. Objective: The objective is to evaluate the patterns of antibiotic resistance among bacterial isolates from CAIs in patients presenting to a tertiary care hospital and to assess their associated clinical outcomes to inform empirical therapy and support antimicrobial stewardship initiatives. Methodology: A descriptive observational study was conducted at the Microbiology Department of Gujranwala Medical College, Gujranwala, Pakistan, from February 11, 2024, to February 11, 2025. The study included 560 individuals with suspected CAIs who tested positive for bacterial infection. Antimicrobial susceptibility testing was performed using the Kirby-Bauer disc diffusion method in accordance with Clinical and Laboratory Standards Institute guidelines. Data analysis was conducted using Statistical Package for the Social Sciences version 26 (IBM Corp., Armonk, NY). Results: Of the 560 patients, 314 (56.07%) were men and 246 (43.93%) were women; 188 patients (33.57%) were aged 18-40 years. The most common specimen was urine (n = 234, 41.79%), followed by blood (n = 112, 20.00%). The predominant pathogens were Escherichia coli (n = 216, 38.57%) and Staphylococcus aureus (n = 104, 18.57%). Among E. coli isolates, 169 (78.24%) showed resistance to ciprofloxacin and 153 (70.83%) to ceftriaxone. Methicillin-resistant S. aureus (MRSA) was identified in 67 of 104 isolates (64.42%). Multidrug-resistant (MDR) organisms were detected in 188 patients (33.57%) and were significantly associated with treatment failure (38.30%), prolonged hospital stay (53.72%), antibiotic escalation (68.62%), and inhospital mortality (11.17%). Carbapenem-resistant infections were found in 32 patients (5.71%), with a mortality rate of 28.13% (n = 9). Conclusion: This study demonstrates a high burden of MDR organisms in CAIs, with poor clinical outcomes, particularly in carbapenem-resistant and MRSA infections. These findings emphasize the urgent need for strengthened antimicrobial stewardship, continuous surveillance of resistance trends, and locally tailored empirical treatment guidelines in community healthcare settings.