Occurrence of <i>Escherichia coli</i>0157:H7 in Diverse Farm Environments in Five States

In the United States, foodborne outbreaks of Escherichia coli O157:H7 illness have often been linked to the consumption of contaminated, undercooked ground beef. However, the occurrence of E. coli O157:H7 in other animals has also been reported. The objective of this study was to determine the occurrence of E. coli O157:H7 in cattle, swine, poultry, and farm environments. Environmental samples (n=576) and fecal swab samples (n=1686) from sixteen locations in the U.S. were collected over 22 months. Overall, in fecal swabs E. coli O157:H7 was positive (serologically confirmed) in 4.7% of beef cattle (n = 408), 3.9% of dairy cattle (n=408), 8.9% of swine (n=426), 7.5% of turkey (n=120) and <1% of chickens (n= 324).

E. coli O157:H7 was isolated infrequently from environmental samples (<3%), except for swine environmental samples (9%). No trends could be established for poultry. E. coli O157:H7 was isolated from feed samples (up to 3 samples) from the states of Tennessee and Washington. Since E. coli O157:H7 was seldom isolated from feeds or bedding, sampling for E. coli 0157 at the farm should focus on the feces or fecal swabs for optimal recovery. The occurrence of E. coli 0157 in swine and turkey was surprisingly high which indicates that swine and turkey may serve as vectors for food-borne outbreaks of E.coli 0157.