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ARS Home » Plains Area » Clay Center, Nebraska » U.S. Meat Animal Research Center » Meat Safety and Quality » Research » Publications at this Location » Publication #235624
Title: Longitudinal Study of Escherichia coli O157:H7 in a Beef Cattle Feedlot and Role of High-Level Shedders in Hide Contamination

Author
item Arthur, Terrance
item KEEN, JAMES - FORMER ARS EMPLOYEE
item Bosilevac, Joseph - Mick
item Harhay, Dayna
item Kalchayanand, Norasak - Nor
item Shackelford, Steven
item Wheeler, Tommy
item Nou, Xiangwu
item KOOHMARAIE, MOHAMMAD - FORMER ARS EMPLOYEE

Submitted to: Applied and Environmental Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/8/2009
Publication Date: 10/15/2009
Citation: Arthur, T.M., Keen, J.E., Bosilevac, J.M., Brichta-Harhay, D.M., Kalchayanand, N., Shackelford, S.D., Wheeler, T.L., Nou, X., Koohmaraie, M. 2009. Longitudinal Study of Escherichia coli O157:H7 in a Beef Cattle Feedlot and Role of High-Level Shedders in Hide Contamination. Applied and Environmental Microbiology. 75(20):6515-6523.

Interpretive Summary: The objective of the study was two-fold: 1) to determine how animals shedding Escherichia coli O157:H7 at high levels (greater than or equal to 200 CFU/g) affect the prevalence and levels of E. coli O157:H7 on the hides of other animals within the same pen; 2) to investigate the dynamics of E. coli O157:H7 fecal and hide prevalence over a 9-month period. Cattle were distributed across ten adjacent pens and fecal and hide levels of E. coli O157:H7 were monitored. The occurrence of one or more high E. coli O157:H7 shedding cattle in a pen was strongly associated with increased pen hide prevalence, increased pen fecal prevalence, and increased numbers of cattle with high hide levels of E. coli O157:H7 (greater than or equal to 40 CFU/100 cm2) in the pen. The occurrence of one or more high fecal E. coli O157:H7 shedding cattle in a pen was strongly associated with the outcome of one or more cattle in a pen with high hide levels of E. coli O157:H7. The results of this study support the hypothesis that high level fecal E. coli O157:H7 shedding prevalence (termed “super-shedders”) is associated with hide and high level hide contamination of cattle. In addition, large and unpredictable fluctuations within and between pens in both fecal and hide prevalence of E. coli O157:H7 were detected and should be used as a guide when designing pre-harvest studies.

Technical Abstract: The objective of the study described here was two-fold: 1) to determine how animals shedding Escherichia coli O157:H7 at high levels (greater than or equal to 200 CFU/g) affect the prevalence and levels of E. coli O157:H7 on the hides of other animals within the same pen; 2) to investigate the dynamics of E. coli O157:H7 fecal and hide prevalence over a 9-month period. Cattle (n=319) were distributed across ten adjacent pens and fecal and hide levels of E. coli O157:H7 were monitored. The occurrence of one or more high E. coli O157:H7 shedding cattle in a pen was strongly associated with increased pen hide prevalence, the odds ratio (OR) was 14.4 (95% CI: 6.5-31.8), increased pen fecal prevalence (OR = 8.8; 95% CI: 4.9-15.8) and increased numbers of cattle with high hide levels of E. coli O157:H7 (greater than or equal to 40 CFU/100 cm2) in the pen (OR = 17.7; 95% CI: 6.5-47.8). The occurrence of one or more high fecal E. coli O157:H7 shedding cattle in a pen was strongly associated with the outcome of one or more cattle in a pen with high hide levels of E. coli O157:H7 (OR = 72.9; 95% CI: 18.7-284). Logistic regression models support the hypothesis that high level fecal E. coli O157:H7 shedding prevalence (termed “super-shedders”) is associated with hide and high level hide contamination of cattle. Large and unpredictable fluctuations within and between pens in both fecal and hide prevalence of E. coli O157:H7 were detected and should be used as a guide when designing pre-harvest studies.