Escherichia coli O157:H7, Campylobacter jejuni, and Salmonella Prevalence in Cull Dairy Cows Marketed in Northeastern Ohio

Abstract

Preharvest management factors are predicted to impact the prevalence of foodborne pathogens in cattle sent to slaughter. We simultaneously examined the prevalence and antibiotic resistance patterns of Campylobacter jejuni, Salmonella, and Escherichia coli O157:H7 isolated from cull dairy cattle at two livestock auctions in northeastern Ohio. Between April and September 2002, a total of 1,026 fecal samples were collected. C. jejuni was isolated from 48 of 686 (7%) fecal samples, Salmonella was isolated from 39 of 585 (6.7%) samples, and E. coli O157:H7 was isolated from 21 of 1,026 (2.1%) samples. Of the 585 samples tested for all three pathogens, at least one pathogen was identified in 86 of 585 (15%) samples. One sample was positive for both E. coli O157:H7 and C. jejuni, and five samples yielded both C. jejuni and Salmonella. Size of herd of origin could be traced for 75 to 85% of samples collected. Salmonella was isolated at higher frequencies from herds larger than 60 cattle than from smaller herds (9.0 versus 3.5%, P = 0.02). In contrast, size of herd of origin did not significantly affect the E. coli O157:H7 and C. jejuni prevalence. Approximately 90% of Salmonella and E. coli O157:H7 isolates were pansensitive to a panel of 16 antibiotics. Thirty-six percent of C. jejuni isolates were resistant to tetracycline. In this study, antibiotic resistance among the foodborne pathogens isolated from cull diary cattle was rare. Although size of dairy herd of origin was positively associated with Salmonella prevalence, herd size was not strongly associated with E. coli O157:H7 and C. jejuni prevalence in market dairy cattle. These results can be used to assess the food safety risks associated with the slaughter of cull dairy cattle.