Transcript Escherichia coli - York College of Pennsylvania

An Investigation of Escherichia coli O157 in Holstein and Simmental Herds in
Central Pennsylvania
Lisa L. Smith
Department of Biological Sciences, York College of Pennsylvania
Methods
Introduction
Escherichia coli O157:H7 is known to cause human food borne
illness. E. coli O157 is a virulent strain of bacteria which produces
verotoxins. Enterohemorrhagic E. coli , which produces verotoxins,
is a major cause of human disease (Naylor et al 2002).Upon
consumption of contaminated food, the verotoxins adhere to the
intestinal tract wherein toxins are produced. The toxins are found to
Results
Test subjects
-10 Holstein
-10 Simmental
All 20 test subjects were found positive for E. coli O157
100% Positive (Figure 1)
Discussion
Prepare Novobiocin
selective
enrichment broth
The purpose of this was to investigate if Escherichia
coli O157 was present in local cattle herds. All
samples collected were found to be positive which
suggests that E. coli O157 infection in local cattle is
cause diarrhea, hemolytic-uremia syndrome, and can in some
instances result in death. The most deaths occurring as a result of
O157:H7 infections are in children, elderly, and immunocompromised individuals. Past research has shown cattle to be
very prevalent. The results however were inconclusive
as to whether there was difference in prevalence
Collect 25g
Fecal Samples
between dairy and beef cattle since all samples were
positive. It is thereby alarming to find that local
carriers of the bacteria. The E. coli O157 is spread through infected
meat, milk, and by causal contact. Over 70,000 cases of E. coli
illness, and about 60 deaths occur annually according to the centers
for disease control. In September 2000, 15 confirmed cases as well
as 36 cases of E. coli O157:H7 infection occurred after the people
had visited a dairy farm. Their illness resulted from casual contact
with the animals. Rarely, cases also stemmed from drinking
unpasteurized milk. The most common source of transmission
however is by consumption of infected meat, usually ground beef.
The purpose of the study was to determine the prevalence of E. coli
Incubate
24 hours 37C
•Investigate whether local dairy and beef cattle are carriers of
Escherichia coli O157.
•Determine the prevalence of infection within the local cattle
population.
•Discern any difference in E. coli O157 prevalence present
among both dairy and beef cattle populations.
invaluable in making the public aware of the risks as
well as informing them to use proper food handling
techniques as well as good hygiene when working
with farm animals. A large scale study in the future
involving a larger sample size, would be helpful in
better determining the prevalence as well as whether
contact with either dairy or beef cattle is a greater
risk.
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Positive E. coli Result
Objectives
enter the food supply via meat, unpasteurized milk,
or by casual contact. The results of this study are
GLISA
E. Coli O157
test kit
O157 in beef and dairy cattle herds, and to determine if there was a
difference in the prevalence between dairy and beef cattle due to
their relative potential impacts on the food supply should they be
found positive.
cattle are carriers of a potentially virulent strain of E.
coli. The potential therefore exists for the bacteria to
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Literature Reviewed
6
Crump, J.A., Sulka, A.C., Langer, A.J., et al. 2002. An outbreak of Escherichia coli
O157:H7 Infections Among Visitors to a Dairy Farm. Journal of the Pennsylvania
Academy of Science 347:8 555-560.
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Montenegro, M.A., Butle, M., Trumpf, T., et al. 1990. Detection and
Characterization of Fecal Verotoxin-Producing Escherichia coli from Healthy
Cattle. Journal of Clinical Microbiology. 28:6 1417-1421.
2
0
Dairy
Beef
Cattle
Figure 1. Displays a positive result
for Escherichia coli O157 in all
samples (n=20)
Naylor, S.W., Low, C., Besser, T.E., et al. 2003 Lymphoid Follicle-Dense Mucosa at
the Terminal Rectum Is the Principal Site of Colonization of Enterohemorrhagic
Escherichia coli O157:H7 in the Bovine Host. Infection and Immunity.71:3 15051512.
Acknowledgements
I wish to thank the following for their continued support and patience:
Carolyn Mathur Ph.D., Karl Kleiner Ph.D., Barbara Taylor M.S., Bradley
Rehnberg Ph.D., and Sally Hoh B.S.