Antibiotic Susceptibility Profiling of Escherichia Coli Isolated from Clinical Urinary Samples at Lancet Laboratories in Bulawayo

Abstract

Background and Problem Statement: Antibiotic resistance in uropathogenic Escherichia coli (UPEC) is an escalating public health threat in Zimbabwe. Limited local surveillance data on E. coli susceptibility patterns in Bulawayo hamper evidence-based antibiotic prescribing, leading to inappropriate empirical therapy and contributing to the spread of resistant strains. This study was therefore conducted to address this critical knowledge gap. Methodology: This retrospective cross-sectional study determined antibiotic susceptibility patterns of Escherichia coli isolated from urine samples at Lancet Laboratories Bulawayo between August 2024 and July 2025. Census sampling was employed, and antibiotic susceptibility testing was performed using the disk diffusion method according to Clinical and Laboratory Standards Institute guidelines. Of 2,847 urine samples with significant bacterial growth, E. coli was isolated from 1,523 (53.5%), confirming its predominance as a uropathogen. After applying exclusion criteria, 1,456 isolates were analysed. The study population comprised 78.4% females with a mean age of 42.6 years. High resistance rates were observed for ampicillin (72.6%), trimethoprim-sulfamethoxazole (52.0%), amoxicillin-clavulanate (36.6%), and ciprofloxacin (36.0%). Preserved susceptibility was noted for carbapenems (imipenem 99.0%, meropenem 99.5%), nitrofurantoin (89.1%), and gentamicin (77.2%). Extended-spectrum beta-lactamase production was identified in 26.7% of isolates, and 52.8% demonstrated multidrug resistance. Significant associations were found between antibiotic resistance and advancing age, hospital acquisition, and ESBL production. Temporal analysis revealed increasing ESBL prevalence from 24.7% to 27.8% across study quarters. These findings underscore the urgent need for revised treatment guidelines, comprehensive antimicrobial stewardship programs, and enhanced surveillance systems to address the escalating antibiotic resistance crisis in Bulawayo, Zimbabwe.