Isolation of shiga-toxigenic Escherichia coli O157 from hide surfaces and the oral cavity of finished beef feedlot cattle

Abstract

Objective - To determine whether viable shiga-toxigenic Escherichia coli (STEC) O157 could be isolated from hide surface locations and the oral cavity of finished beef feedlot cattle. Design - Within-animal prevalence distribution survey. Animals - 139 finished cattle in 4 pens in a feedlot in Nebraska; prevalence of fecal STEC O157 shedding ranged from 20 to > 90%. Procedure - Samples were collected from 7 sites from each animal: feces, oral cavity, and 5 hide surface locations (lumbar region, ventral aspect of the neck, ventral abdominal midline [ventrum], dorsal thoracic midline [back], and distal aspect of the left hind limb [hock]). Results - Viable STEC O157 were isolated from the oral cavity or 1 or more hide surfaces of 130 cattle, including 50 fecal isolation-negative cattle. Site-specific prevalence of STEC O157 was 74.8% for oral cavity samples, 73.4% for back samples, 62.6% for neck samples, 60.4% for fecal samples, 54.0% for flank samples, 51.1% for ventrum samples, and 41.0% for hock samples. Only 5 cattle tested negative for STEC O157 at all 7 sites. Multiple correspondence and cluster analyses demonstrated that bacterial culture of feces, oral cavity samples, and back samples detected most cattle with STEC O157. Conclusions and Clinical Relevance - Results suggest that viable STEC O157 may be isolated from the oral cavity, multiple hide surfaces, and feces of a high percentage of fed beef cattle and that bacterial culture of feces alone generally underestimates the percentage of fed beef cattle from which STEC O157 can be isolated.