Escherichia coli O157:H7

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Escherichia coli O157H7

• Javier Chavez
• Cathy Miller
• Meridith Phillips
• Patty Roth

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Introduction

• What is E. coli?
• Vocabulary
• How is it spread?
• What are the symptoms?
• Who does it affect?
• What is the treatment?

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What is E. coli?

• Esherichia coli O157H7 is one of hundreds of
  strains of the bacterium Eshcherichia coli.
• Most strains live in the intestines of healthy
  humans and animals, this strain produces a
  powerful toxin, veritoxin, which can cause severe
  illness and death.
• O represents the surface somatic polysaccharide
  antigen used for typing
• H refers to the flagella atogen
• 157H7 is singled out as the most likely to cause
  HUS and death

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Vocabulary

• Infectious dose- how many bacteria are necessary
  to infect and organism
• Attack rate- the number of individuals exposed to
  and infectious dose who contract the disease
• Sequelae- the outcome of the infection
• Transmissible- food born diseases are
  transmissible by the fecal-oral route.
• Variability- there is variability in the organism
  and the host.
• Food matrix- the human intestinal system lives in
  permanent association with many types of
  microorganisms. The diet of the host,
  physiological state and genetics of the host
  affects the microorganisms

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Background

• First identified in 1982
• 1992-1993 Jack in the Box food chain outbreak had
  500 laboratory-confirmed infections or deaths
• 1996 Odwalla juice outbreak illness affected 45
  people
• 1996, 3000 cases linked to radish sprouts in
  school lunch program
• 2000, 2300 became ill, 7 deaths from water
  contaminated with E. coli from flooding

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5 Year Trends in Colorado

• www.cdphe.state.co.us/dc/EIP/eco.asp
• Escherichia coli O157H7 is a Shiga toxin
  producing bacterium that can cause illness
  ranging from mild intestinal illness to severe
  kidney complications. Other Shiga toxin
  producing serotypes (e.g. O111 and O26) are also
  in the family of enterohemorrhagic E. coli and
  can cause similar disease.

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How is it spread?

• The organism can be found in the intestines of
  healthy cattle. The meat can be contaminated
  during slaughter.
• Can be mixed into beef when it its ground into
  hamburger.
• Bacteria on cows udders or on equipment can get
  into raw milk
• It can contaminate fruits and vegetables from
  contact with manure used as fertilizer
• Drinking water contaminated with sewage can carry
  the bacteria
• The infectious dose is usually under 100
  organisms
• Can be spread by person to person contact

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Who does it affect?

• E. coli O157H7 generally affects the young
  (including teens) and the elderly

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What are the symptoms?

• Diarrhea and malaise
• Hemorrhagic colitis(HC) or bloody diarrhea and
  abdominal cramps
• Lasts for 5-10 days usually
• Infection may proceed to Hemolytic Uremic
  Syndrome (HUS), a severe cytopathic attack on the
  kidneys requiring intensive care and dialysis.
  Red blood cells are destroyed requiring blood
  tranfusion

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Treatment

• Most persons recover without antibiotics or
  specific treatment in 5-10 days.
• Some antibiotic treatments cause kidney
  complications
• Antidiarrheal agents should be avoided

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Prevention

• Cook all beef thoroughly (with no pink in center)
• Avoid eating undercooked meat at restaurants
  (send it back)
• Keep cooking area clean, wash your hands with hot
  soapy water
• Keep raw meat away from read-to eat foods
• Drink pasteurized milk and juices
• Wash fruits and vegetables
• Avoid swallowing lake or swimming pools water

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References

• Center for Disease Control, June 2001
• http//www.cdc.gov/ncidod/dbmd/diseaseinfo/escheri
  chiacoli_g.htm (Search under What is Escherichia
  coli O157H7)