Groundwater plays a crucial role in agricultural water supply in rural areas, but it is susceptible to contamination due to intensive agricultural activities and inadequate management. This study investigates the contamination status of Escherichia coli in groundwater from an agricultural region and characterizes the phylogroups and virulence factors of the isolated E. coli strains. A total of 140 E. coli strains were isolated from groundwater in the study area. Phylogenetically, Group A was the most abundant (47.9%), followed by Group B1 (25.0%), Group D (22.1%), and Group B2 (5.0%). Among the isolated E. coli strains, the detection frequency of major virulence genes was highest for stx₂(35.0%), followed by ibeA (29.3%) and stx₁ (12.9%). Pathotype analysis revealed that Shiga toxin-producing E. coli (STEC) accounted for 45.7%, and Neonatal Meningitis E. coli / Avian Pathogenic E. coli (NMEC/APEC) was also identified in 20.0%. These results suggest that groundwater in agricultural areas can be contaminated by various pathogenic E. coli strains, particularly STEC, which poses significant implications for groundwater hygiene management and public health. Therefore, continuous monitoring and the establishment of effective management systems for contamination sources are necessary for the safe and sustainable use of groundwater in agricultural areas.

Keywords: Groundwater, Agricultural area, Escherichia coli, Phylogenetic group, Virulence gene