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Studies in Shiga toxin-producing Escherichia coli O157:H7: determination of factors contributing to the dissemination of Escherichia coli O157:H7 among dairy farms

Wetzel, Amy Noel
http://rave.ohiolink.edu/etdc/view?acc_num=osu1133239436

Abstract Details

2005, Doctor of Philosophy, Ohio State University, Veterinary Preventive Medicine.
Shiga toxin-producing Escherichia coli (STEC) O157:H7 is an important foodborne disease worldwide, and cattle play a central role in the epidemiology of human E. coli O157:H7 infection. Cattle feces are considered the primary source from which the food supply and the environment become contaminated with this pathogen. Therefore, reduction in the frequency and magnitude of fecal E. coli O157:H7 excretion by cattle is predicted to decrease the incidence of human infection. Escherichia coli O157:H7 has been sporadically isolated from other animals, and environmental sources. However, the primary routes of dissemination of E. coli O157:H7 within and between farms remains undetermined. The hypothesis that European starlings play a role in the dissemination of E. coli O157:H7 between cattle farms was tested by determining if starlings inhabiting Ohio dairy farms are a source for E. coli O157:H7 and other foodborne pathogens, and evaluating the extent to which indistinguishable isolates of E. coli O157:H7 were shared between dairy farms located in a close geographic proximity. Cultured intestinal contents of starlings captured on Ohio dairy farms showed that starlings seasonally harbor E. coli O157:H7 (late summer 20%, winter 0%) and other STEC (62.5%). Stx-negative O157 isolates could be lysogenized by stx2-converting bacteriophage, indicating that these toxin-negative strains may acquire stx2. Pulsed-field gel electrophoresis analysis of E. coli O157:H7 isolates recovered during a longitudinal study of 20 dairy farms in Ohio showed E. coli O157:H7 subtypes (four indistinguishable subtypes) were disseminated with considerable frequency among farms (7 of 20) in close geographic proximity and non-bovine sources may have contributed to the transmission of this organism between farms. In summary, these data support a role of wild birds in the dissemination of E. coli O157:H7 among dairy farms, but the extent of their role in dissemination of this pathogen is yet to be determined.
Jeffrey LeJeune (Advisor)
Biology, Microbiology
E. coli O157:H7; European starlings; clonal dissemination

Recommended Citations

Citations

  • Wetzel, A. N. (2005). Studies in Shiga toxin-producing Escherichia coli O157:H7: determination of factors contributing to the dissemination of Escherichia coli O157:H7 among dairy farms [Doctoral dissertation, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1133239436

    APA Style (7th edition)

  • Wetzel, Amy. Studies in Shiga toxin-producing Escherichia coli O157:H7: determination of factors contributing to the dissemination of Escherichia coli O157:H7 among dairy farms. 2005. Ohio State University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1133239436.

    MLA Style (8th edition)

  • Wetzel, Amy. "Studies in Shiga toxin-producing Escherichia coli O157:H7: determination of factors contributing to the dissemination of Escherichia coli O157:H7 among dairy farms." Doctoral dissertation, Ohio State University, 2005. http://rave.ohiolink.edu/etdc/view?acc_num=osu1133239436

    Chicago Manual of Style (17th edition)

osu1133239436
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This open access ETD is published by The Ohio State University and OhioLINK.