Widespread Multidrug Resistance and Virulence Determinants in Escherichia coli Across the Interconnected Farm-to-Food Continuum.

BACKGROUND/

OBJECTIVES

Globally, the management of infections has been complicated greatly by the rapid emergence of antibiotic resistance among bacterial pathogens, particularly Escherichia coli (E. coli). This bacterium is commonly found in a wide range of vertebrate hosts, including livestock, which can serve as important sources of specific pathogenic or multidrug-resistant strains. Cross-contamination can occur from farm to food, posing public health concerns.

METHODS

This cross-sectional study examined the antibiotic resistance and virulence gene profiles of E. coli isolated from farm animals, food processing facilities (including meat and contact surfaces), and the surrounding environment (wastewater).

RESULTS

Out of 383 samples, 230 samples (60.1%) were positive for E. coli (95% CI: 55.1-64.9). The prevalence rates showed significant variation across different sources, with positive rates of 72.3% (180/249) in animal sources, 33.7% (28/83) in food sources, and 43.1% (22/51) in environmental sources. Over 80% of the isolates across all sources carried the sheA virulence gene, which is associated with hemolytic activity in E. coli. Multidrug resistance (MDR) was commonly observed, with rates of 61.1% in animal samples, 57.1% in food sources, and 50.0% in environmental samples. The E. coli isolates exhibited high levels of antibiotic resistance, particularly to streptomycin (64.9%), ampicillin (58.0%), and tetracycline (57.6%). The most common resistance gene pattern was tetA-strA-blaTEM (22.6%).

CONCLUSIONS

These findings indicate widespread occurrence of antibiotic-resistant and virulence gene-carrying E. coli strains across the farm-to-food continuum, underscoring the urgent need for enhanced antimicrobial stewardship and surveillance programs to mitigate transmission from food-producing animals and reduce public health complications.