Difference between revisions of "Escherichia coli enterohemorrhagic (EHEC): Dose Response Models"

From QMRAwiki
Jump to: navigation, search
Line 1: Line 1:
 
{{Buttons - Escherichia coli enterohemorrhagic (EHEC): Dose Response Models}}
 
{{Buttons - Escherichia coli enterohemorrhagic (EHEC): Dose Response Models}}
  
==='''Overview: EHEC and disease caused by it'''===
+
==='''Overview: EHEC and HUS (Hemolytic uremic syndrome)'''===
  
''Escherichia coli'' usually resides as a commensal bacterium in the mammalian large intestine, benefiting itself as well as the host. Enterohemorrhagic ''E. coli'' (EHEC; particularly serotype O157:H7) is a highly pathogenic variant which can cause life-threatening disease and has been the cause of many major outbreaks from fecally contaminated food (e.g., ground beef)<ref name="Strachan et al 2005">Strachan NJC et al. (2005) Dose response modelling of Escherichia coli O157 incorporating data from foodborne and environmental outbreaks. International Journal of Food Microbiology. 103(1), pp.35-47. [http://www.sciencedirect.com/science?_ob=MImg&_imagekey=B6T7K-4FNCW2P-2-7&_cdi=5061&_user=1111158&_pii=S0168160505000693&_origin=gateway&_coverDate=08%2F15%2F2005&_sk=998969998&view=c&wchp=dGLbVzW-zSkzk&md5=bc35dbff2f730b099c8a5dabd9fe1baa&ie=/sdarticle.pdf Full Text]</ref> EHEC may also spread through contaminated drinking water as evidenced by the outbreak in Walkerton, Ontario following heavy rains<ref name="Auld et al. 2004">Auld H, MacIver D & Klaassen J (2004) Heavy rainfall and waterborne disease outbreaks: the Walkerton example. Journal of Toxicology and Environmental Health. Part A. 67(20-22), pp.1879-1887. [http://docserver.ingentaconnect.com/deliver/connect/tandf/15287394/v67n20/s25.pdf?expires=1302533913&id=62221784&titleid=1278&accname=MICHIGAN+STATE+UNIVERSITY&checksum=2B7EDA587378C6DB157082DB0FDF38BC Full Text]</ref>
+
''Escherichia coli'' resides as a commensal gram negative bacterium in the mammalian and bird intestinal tract and is excreted in feces. Enterohemorrhagic ''E. coli'' (EHEC; particularly serotype O157:H7) is a highly pathogenic variant which can cause life-threatening disease and has been the cause of many major outbreaks from fecally contaminated food (e.g., ground beef)<ref name="Strachan et al 2005">Strachan NJC et al. (2005) Dose response modelling of Escherichia coli O157 incorporating data from foodborne and environmental outbreaks. International Journal of Food Microbiology. 103(1), pp.35-47. [http://www.sciencedirect.com/science?_ob=MImg&_imagekey=B6T7K-4FNCW2P-2-7&_cdi=5061&_user=1111158&_pii=S0168160505000693&_origin=gateway&_coverDate=08%2F15%2F2005&_sk=998969998&view=c&wchp=dGLbVzW-zSkzk&md5=bc35dbff2f730b099c8a5dabd9fe1baa&ie=/sdarticle.pdf Full Text]</ref> and drinking water as evidenced by the outbreak in Walkerton, Ontario following heavy rains<ref name="Auld et al. 2004">Auld H, MacIver D & Klaassen J (2004) Heavy rainfall and waterborne disease outbreaks: the Walkerton example. Journal of Toxicology and Environmental Health. Part A. 67(20-22), pp.1879-1887. [http://docserver.ingentaconnect.com/deliver/connect/tandf/15287394/v67n20/s25.pdf?expires=1302533913&id=62221784&titleid=1278&accname=MICHIGAN+STATE+UNIVERSITY&checksum=2B7EDA587378C6DB157082DB0FDF38BC Full Text]</ref>
  
 
EHEC is technically part of the larger group of Shiga toxin producing ''E. coli'' (STEC), many of which cause little or no disease. EHEC attaches to the large intestinal wall and produces ‘attaching and effacing lesions’, which can cause bloody or non-bloody diarrhea, as well hemorrhagic colitis and hemolytic uremic syndrome (HUS). Its principal reservoir is the bovine intestinal tract. It has a lower ID50 than other pathogenic E. coli types <ref name="Kaper 2004">Kaper JB, Nataro JP & Mobley HL (2004) Pathogenic Escherichia coli. Nature Reviews. Microbiology. 2(2), pp.123-140. [http://www.nature.com/nrmicro/journal/v2/n2/full/nrmicro818.html Full Text]</ref><ref name="Nataro 1998">Nataro JP & Kaper JB (1998) Diarrheagenic Escherichia coli. Clinical Microbiology Reviews. 11(1), pp.142-201. [http://cmr.asm.org/cgi/reprint/11/1/142 Full Text]</ref>
 
EHEC is technically part of the larger group of Shiga toxin producing ''E. coli'' (STEC), many of which cause little or no disease. EHEC attaches to the large intestinal wall and produces ‘attaching and effacing lesions’, which can cause bloody or non-bloody diarrhea, as well hemorrhagic colitis and hemolytic uremic syndrome (HUS). Its principal reservoir is the bovine intestinal tract. It has a lower ID50 than other pathogenic E. coli types <ref name="Kaper 2004">Kaper JB, Nataro JP & Mobley HL (2004) Pathogenic Escherichia coli. Nature Reviews. Microbiology. 2(2), pp.123-140. [http://www.nature.com/nrmicro/journal/v2/n2/full/nrmicro818.html Full Text]</ref><ref name="Nataro 1998">Nataro JP & Kaper JB (1998) Diarrheagenic Escherichia coli. Clinical Microbiology Reviews. 11(1), pp.142-201. [http://cmr.asm.org/cgi/reprint/11/1/142 Full Text]</ref>
  
It is unethical to conduct feeding experiments on humans with EHEC due to its virulence. However, feeding experiments on animals have been conducted. Information from EHEC outbreaks in humans has also been used to inform dose response models.
+
It is unethical to conduct feeding experiments on humans with EHEC due to its virulence. However, feeding experiments on animals have been conducted. Information from EHEC outbreaks in humans has also been used to inform dose response models <ref name="Teunis 2004">.
 +
 
 +
http://www.cdc.gov/ecoli/index.html
  
 
===References===
 
===References===

Revision as of 16:08, 26 November 2012

Overview: EHEC and HUS (Hemolytic uremic syndrome)

Escherichia coli resides as a commensal gram negative bacterium in the mammalian and bird intestinal tract and is excreted in feces. Enterohemorrhagic E. coli (EHEC; particularly serotype O157:H7) is a highly pathogenic variant which can cause life-threatening disease and has been the cause of many major outbreaks from fecally contaminated food (e.g., ground beef)[1] and drinking water as evidenced by the outbreak in Walkerton, Ontario following heavy rains[2]

EHEC is technically part of the larger group of Shiga toxin producing E. coli (STEC), many of which cause little or no disease. EHEC attaches to the large intestinal wall and produces ‘attaching and effacing lesions’, which can cause bloody or non-bloody diarrhea, as well hemorrhagic colitis and hemolytic uremic syndrome (HUS). Its principal reservoir is the bovine intestinal tract. It has a lower ID50 than other pathogenic E. coli types [3][4]

It is unethical to conduct feeding experiments on humans with EHEC due to its virulence. However, feeding experiments on animals have been conducted. Information from EHEC outbreaks in humans has also been used to inform dose response models <ref name="Teunis 2004">.

http://www.cdc.gov/ecoli/index.html

References

  1. Strachan NJC et al. (2005) Dose response modelling of Escherichia coli O157 incorporating data from foodborne and environmental outbreaks. International Journal of Food Microbiology. 103(1), pp.35-47. Full Text
  2. Auld H, MacIver D & Klaassen J (2004) Heavy rainfall and waterborne disease outbreaks: the Walkerton example. Journal of Toxicology and Environmental Health. Part A. 67(20-22), pp.1879-1887. Full Text
  3. Kaper JB, Nataro JP & Mobley HL (2004) Pathogenic Escherichia coli. Nature Reviews. Microbiology. 2(2), pp.123-140. Full Text
  4. Nataro JP & Kaper JB (1998) Diarrheagenic Escherichia coli. Clinical Microbiology Reviews. 11(1), pp.142-201. Full Text