Longitudinal Study of Fecal Shedding of Escherichia coli O157:H7 in Feedlot Cattle: Predominance and Persistence of Specific Clonal Types despite Massive Cattle Population Turnover

• DOI: 10.1128/aem.70.1.377-384.2004
• Publication Date: 2004-01-07T21:02:54Z
• Authors: J. T. LeJeune; T. E. Besser; D. H. Rice; J. L. Berg; R. P. Stilborn; D. D. Hancock
• Keywords: 0301 basic medicine; 2. Zero hunger; Cattle Diseases; Fresh Water; Escherichia coli O157; Animal Feed; 6. Clean water; Electrophoresis, Gel, Pulsed-Field; Feces; 03 medical and health sciences; Prevalence; Animals; Cattle; Longitudinal Studies; Escherichia coli Infections

ABSTRACT

Identification of the sources and methods of transmission of Escherichia coli O157:H7 in feedlot cattle may facilitate the development of on-farm control measures for this important food-borne pathogen. The prevalence of E. coli O157:H7 in fecal samples of commercial feedlot cattle in 20 feedlot pens between April and September 2000 was determined throughout the finishing feeding period prior to slaughter. Using immunomagnetic separation, E. coli O157:H7 was isolated from 636 of 4,790 (13%) fecal samples in this study, with highest prevalence earliest in the feeding period. No differences were observed in the fecal or water trough sediment prevalence values of E. coli O157:H7 in 10 pens supplied with chlorinated drinking water supplies compared with nonchlorinated water pens. Pulsed-field gel electrophoresis of Xba I-digested bacterial DNA of the 230 isolates obtained from eight of the pens revealed 56 unique restriction endonuclease digestion patterns (REDPs), although nearly 60% of the isolates belonged to a group of four closely related genetic subtypes that were present in each of the pens and throughout the sampling period. The other REDPs were typically transiently detected, often in single pens and on single sample dates, and in many cases were also closely related to the four predominant REDPs. The persistence and predominance of a few REDPs observed over the entire feeding period on this livestock operation highlight the importance of the farm environment, and not necessarily the incoming cattle, as a potential source or reservoir of E. coli O157:H7 on farms.