Prevalence and Antimicrobial Resistance of Escherichia coli Isolated from Selected Farms (Lettuce, Soil and Irrigation Water) Surrounding the Benue River in Garoua, North-Cameroon

Abstract

The contamination of fresh vegetables with antimicrobial-resistant bacteria is a threat to food safety, especially in regions with poor agricultural hygienic practices. To investigate the prevalence and antimicrobial resistant (AMR) Escherichia coli in selected farms around the Benue River, we conducted a cross-sectional study from April 01st to 31st May 2025. A total of 170 samples including lettuce, soil, and irrigation water were collected from five small farms. Standard microbiological techniques were used for isolation and identification of E. coli, while antibiotic susceptibility testing was performed on confirmed isolates using the Kirby-Bauer disk diffusion method. Out of the 170 collected samples (lettuce:85, soil:75, and water:10), 79 (46.47%) were tested positive for E. coli. The highest contamination rate was found in lettuce (55.3%), followed by irrigation water (50%) and soil (36%). The resistance profile revealed a high prevalence of multidrug resistant (≥ 3 antibiotic classes) strains across all matrices. Lettuce isolates exhibited the highest resistance to Amoxicillin-clavulanate (87.23%), Ceftazidime (82.98%), and Ciprofloxacin (87.23%). Irrigation water isolates showed 100% resistance to almost all tested betalactam antibiotics (except for meropenem 100% sensitive). Soil isolates presented a resistance rate of (59.26%) to cefotaxime and Fosfomycin. ESBL phenotypes were also present in each sample type with 16.47% in lettuce, 6.66% in soil and 30% in irrigation water. These results reveal the prevalence of E. coli exhibiting MDR in farms surrounding the Benue River, with lettuce potentially acting as a key transmission vector of resistant strains to consumers. These findings underscore the urgent need for integrated One Health interventions, including farmer training, water treatment, and AMR awareness programs to safeguard food safety and public health.