Historic, Archive Document Do not assume content reflects current scientific knowledge, policies, or practices. United States Department of — Escherichia coli 0157:H7 inspection Shedding by Feedlot Cattle _ Veterinary National Animal Health Monitoring System™ aes oma a Ve \ Intense interest has focused on Table 1. Percent of samp\es positive for 4 Escherichia coli 0157:H7 since the Escherichicoal i O457:H7. early 1993 outbreak of foodborne Number Number Percents. Percent of infection in several western states. ample PO E Yael Ositive _ Positive A number of governmental Shortest 2,988 90 3.01 47.1 agencies and animal industry groups Longest 2,963 32 1.08 16.8 have expended a great deal of effort Random 5,930 _69 1.16 mo6. | to collect more information about the =y oy) 11,881 191 1.61 100.0 pathogen and it’s ecology. The recently completed Cattle on Feed Evaluation (COFE) confirms findings from other studies which indicate that — longest period of time were least likely to be the organism occurs in animal populations at low positive for E. coli O157:H7 (1.08 percent of frequency but is widely distributed. samples). E. coli 0157:H7-positive feedlots were widely distributed. Overall, the organism was In the fall of 1994, the USDA’s National detected in one or more samples from 63 percent Animal Health Monitoring System (NAHMS) of the feedlots. Feedlots from the more southern collected data on health and management of cattle latitudes were more likely to be positive (71.9 on a broad-based sample of feedlot operations percent) compared to the middle (59.4 percent) from the 13 major cattle feeding states (Figure and northern (58.3 percent) latitudes (Figure 1). 1). In addition, 100 volunteer feedlots were enlisted to provide samples to be tested for E. All E. coli O157:H7 isolates possessed the coli 0157:H7. The 100 feedlots were distributed genetic material to code for the production of one across the 13 states roughly proportional to the number of cattle on feed in those states. Figure 1 In each feedlot, the pen of cattle that had Percent of Feedlots Positive for Escherichia coli 0157:H7 been on feed the shortest amount of time and in Participating States by Region the pen of cattle that had been on feed the longest amount of time were selected for feces collection. In addition, two other pens (if available) were selected at random for sampling. From each pen, 30 swab samples were collected from fresh feces on the pen floor and tested for E. coli O157:H7. Overall, E. coli O157:H7 was recovered Middle: 59.4% from 1.61 percent of the samples collected (Table 1). E. coli O157:H7 was most commonly recovered from the pens of cattle Southern: 71.9% that had been on feed the shortest period of #2886 time (3.01 percent of samples). Samples from pens of cattle that had been on feed the May 1995 AMINO 1022400816 : ; Or DOT OF tne toxms thought to be important in operations.” From these tentative associations, the pathogenesis of human disease (Shiga-like targeted studies will define factors which toxin 1 and Shiga-like toxin 2).! modulate shedding. Such studies may eventually lead to strategies for decreasing the shedding of These data would seem to indicate that the E. the organism. coli 0157:H7 organism is widely distributed in feedlot cattle populations, but the prevalence is very low. These findings are similar to other NAHMS collaborators on the COFE included the cattle populations that have been evaluated, such National Agricultural Statistics Service (USDA); State and as dairy cattle and calves. Federal Veterinary Medical Officers; the National Veterinary Services Laboratories (USDA:APHIS:VS); and the Field Disease Investigation Unit, Washington State The percent of samples positive for E. coli University. 0157:H7 in a pen varied from none to 36.7 percent. On a feedlot basis, the percent of total Other information from the COFE is available on feedlot samples positive for E. coli 0157:H7 varied from quality assurance measures, environmental monitoring, 0.0 to 10.0 percent. The variation in percent of injection practices, and vaccination practices. For more samples positive per feedlot suggests that the information on these topics or the study in general contact: agent may be amenable to reduction through Centers for Epidemiology & Animal Health management changes. The next phase of analysis USDA:APHIS:VS, Attn. NAHMS of these data will focus on associations between 555 South Howes, Suite 200 management practices (general and nutritional) Fort Collins, Colorado 80521 (970) 490-7800 and number of positive samples. An increased or Internet: [email protected] decreased likelihood of shedding of the organism has been tentatively associated with a variety of N182.595 management factors in studies of dairy 1 Three isolates not available to be probed for the genetic coding for toxin production. 2 Reports discussing these findings are available from the address shown above.