Risk factors forEscherichia coliO157 on beef cattle ranches located near a major produce production region

Abstract

SUMMARYOur goal was to identify climate variables and management practices associated with the presence ofE. coliO157 in rangeland cow-calf operations located in a major leafy green production region in the California Central Coast.E. coliO157 was present in 2·6% (68/2654) of faecal, 1·5% (3/204) of water and 1·1% (1/93) of sediment samples collected on eight ranches over 2.5 years. Five (62·5%) ranches were positive at least once during the study. The odds of detectingE. coliO157 in faecal samples was higher during periods of higher maximum soil temperature, higher maximum relative humidity, and larger herd sizes, but decreased as wind speed increased. Molecular subtyping of isolates from cattle faeces and streams/sediments suggested minimal movement of strains between ranches. The findings suggest thatE. coliO157 prevalence is relatively low on cow-calf ranches in this region, spatially constrained, but may vary by weather conditions and herd size.