Prevalence and Antimicrobial Resistance Patterns of Escherichia coli Causing Urinary Tract Infections: A Retrospective Study at a Tertiary Care Hospital in Karachi, Pakistan

Sadia Talib; Syeda Hira  Abid; Umber  Adnan; Shomaila  Malik; Tahera  Kadir; Fatima  Sana

doi:10.37185/

Authors

Sadia Talib Karachi Institute of Medical Sciences (KIMS), Karachi, Pakistan
Syeda Hira Abid Karachi Institute of Medical Sciences (KIMS), Karachi, Pakistan
Umber Adnan Karachi Institute of Medical Sciences (KIMS), Karachi, Pakistan
Shomaila Malik Karachi Institute of Medical Sciences (KIMS), Karachi, Pakistan
Tahera Kadir Karachi Institute of Medical Sciences (KIMS), Karachi, Pakistan
Fatima Sana Karachi Institute of Medical Sciences (KIMS), Karachi, Pakistan

DOI:

https://doi.org/10.37185/

Keywords:

Antimicrobial Resistance, Escherichia coli, Pakistan, Urinary Tract Infections

Abstract

Objective: To determine the prevalence and patterns of antibiotic resistance of Escherichia coli isolated from urinary tract infection patients.
Study Design: Retrospective cross-sectional study.
Place and Duration of Study: This study was conducted at the Department of Microbiology, Combined Military Hospital (CMH), Karachi, Pakistan, from January 2024 to December 2024.
Methods: Urine samples received from hospitalized patients with clinical features of urinary tract infection were processed using standard microbiological techniques. Isolates were identified as Escherichia coli by conventional biochemical methods. The Kirby-Bauer disk diffusion method was used to test for antimicrobial susceptibility in compliance with Clinical and Laboratory Standards Institute (CLSI) M100, 33^rd Edition, 2023 guidelines. The combined disk diffusion method was used to detect the production of extended-spectrum beta-lactamase. Demographic and clinical data were analyzed using statistical software 25, and associations were assessed using appropriate statistical tests.
Results: A total of 453 non-duplicate Escherichia coli isolates were recovered from urine samples. Female patients accounted for 60% of cases, while male patients accounted for 40%. The highest frequency of infection among females was observed in the 20–40-year age group, whereas infections in males were more common in older age groups. Resistance was universal to amoxicillin and markedly high to beta-lactam and beta-lactamase inhibitor combinations, cephalosporins, fluoroquinolones, aminoglycosides, and trimethoprim-sulfamethoxazole. Nitrofurantoin and carbapenems showed comparatively lower rates of resistance. Extended-spectrum beta-lactamase–producing isolates constituted a substantial proportion of cases, indicating limited therapeutic options.
Conclusion: The research shows that urinary Escherichia coli isolates from a tertiary care hospital setting exhibit a high level of antibiotic resistance. The predominance of extended-spectrum beta-lactamase–producing strains highlights the urgent need for rational antibiotic prescribing, routine culture-based therapy, and strengthened antimicrobial stewardship programs.

How to cite this: Talib S, Abid SH, Adnan U, Malik S, Kadir T, Sana F. Prevalence and Antimicrobial Resistance Patterns of Escherichia coli Causing Urinary Tract Infections: A Retrospective Study at a Tertiary Care Hospital in Karachi, Pakistan. Life and Science. 2026; 7(3): 285-290. doi: http://doi.org/10.37185/LnS.1.1.1066