Transcript Escherichia Coli

Also known as E. coli
Presentation by:
Katie Langlitz
• In 1885, Dr. Theodor von Escherich, a
german pediatrician and bacteriologist,
first discovered this species in the fecal
matter of healthy individuals. He called it
bacterium coli commune, due to the fact it
is found in the colon. It can also be found
in the healthy human intestinal tract and
comes in multiple forms. One group of E.
coli produces a powerful toxin that
damages the lining of the small intestine.
Early classifications of prokaryotes placed
these in a handful of genera based on their
shape and motility.
• This bacterium was later reclassified as
Bacillus coli in 1895 and then later
reclassified again as Escherichia, named
after its original discoverer Dr Theodor von
Escherich.
• E. coli was thought to have originated in its
first strains/forms about 102 million years
ago (WOW!).
Sandy woke one morning with an upset stomach but thought nothing
of this discomfort and proceeded on with her day. As the day
progressed, she began to experience severe abdominal cramping
followed by a low grade fever, nausea, vomiting, and diarrhea. This
persisted for several hours before she was taken to the emergency
room. Upon arrival, they drew her blood for testing, and collected
and tested a stool sample. Results determined that Sandy had
contracted a strain of E. coli. After recounting the , she pinpointed
the assumed source of the infection; Sandy and her family had gone
out for a quick bite to eat at the local taco bell three nights prior
where she ordered a few soft tacos which she had initially thought
the ground beef to have been slightly rare. The infection lasted about
a week and unfortunately, doctors recommended that she let the
infection run its course. The use of antibiotics may increase the risk of
developing post-diarrheal hemolytic uremic syndrome. The best
recommended action for Sandy was to stay hydrated and full of
nutrients. She was fully recovered two weeks later.
• Pathogen Type: E. coli is a bacterium. • Staining Characteristics: E. coli is a
•Size: E. coli is about one-hundredth
the size of a human cell (about a
micron long and one-tenth of a
micron wide).
•Shape: E. coli has a distinctive,
capsule shape.
•Motility: This bacterium is highly
motile. Some strains have flagella or
pili that allow the bacteria to move
and attach to human cells.
gram negative bacterium meaning it
has a thin wall of peptidoglycan and
an outer membrane containing
lipopolysaccharide appearing pink
under a microscope after the gram
stain process is complete.
•Culture Characteristics: This
bacterium grows as fermenting
colonies; some beta hemolysis upon
initial isolation.
•Growth/Metabolic Characteristics: E.
coli can grow in the presence or
absence of oxygen, meaning it is a
facultative anaerobe.
Virulence Factors
• Flagella or Pilli that help the
bacteria move about the cell and
attach to human cells.
• Has a distinctive capsule shape
that allows for protection and
prevention of phagocytosis.
•These bacteria commonly live in
•Inside the membrane is a cytoplasm, the intestines of people and
animals. They are typically not
made up of millions of enzymes,
harmful to the host unless
sugars, ATP and other molecules
absorbed into the tissues.
floating freely in the liquid.
•E. coli bacteria contain shiga-like
toxins that inactivate ribosomes of
eukaryotes blocking mRNA
translation causing cell death.
•Bacterial adhesion onto
mucosal or urothelial cells is
important in determining
bacterial virulence.
•Two closely spaced membranes
protecting the cell.
The most common symptoms seen in most
strains of E. coli are:
• bloody diarrhea
• stomach cramps
• nausea
• vomiting
However, some strains of E. coli can cause
severe anemia, kidney failure, or urinary
tract infections.
Once a person comes in contact with the
E. coli bacterium, the bacteria rapidly
multiply in the large intestine and bind
tightly to cells in the intestinal lining. Most
common in young children and older adults,
some strains of E. coli can lead to hemolytic
uremic syndrome, a condition affecting the
kidneys leading them to shut down which
can be deadly if not treated immediately.
This snug attachment to cells in
the intestinal lining aids in
facilitating absorption of the
toxic bacteria into the small
capillaries within the bowel
where it attaches to Gb3
receptors. This inflammation
caused by the toxin is believed to
be the cause of hemorrhagic
colitis. This is the first symptom
of E. coli, characterized by the
sudden onset of abdominal pain
and severe cramps followed
within 24 hours by diarrhea. The
first of these symptoms occur
within 2-5 days after ingestion of
E. coli. The incubation period
may be as broad as 1-10 days.
Escherichia coli can be directly transmitted in the following ways:
Contaminated Food; most commonly ground beef, unpasteurized milk, and
fresh produce. Contaminated water, animals, and humans (i.e. personal
contact) are other modes of transmission. E. coli lives naturally in the intestines
of humans and animals and does not cause harm. However, if a person ingests
food contaminated with E. coli, it can cause harm to that person if the bacteria
gets into the tissues. A person can get sick from products contaminated with
E. coli if the food or water comes into contact with the feces from a human or
animal and becomes ingested. It is very important to wash vegetables, fruits,
cooking meats thoroughly, as well as washing your hands after using the
restroom to prevent contamination between yourself and others.
Escherichia coli is usually confirmed by
the detection of the bacteria in a stool
specimen collected from an infected
individual. This bacteria can also be
cultured in a laboratory to confirm the
diagnosis and identify specific toxins
and forms of E. coli.
Most hospital professionals
such as physicians, nurses,
and laboratory technicians
know to test for these
particular bacteria,
especially if the infected
individual has bloody
diarrhea.
In most cases of E. coli, infected individuals will have an infection that
lasts about a week and will then resolve without any long term
problems. Antibiotics typically do not improve the illness, and some
medical researchers believe that these medications can actually
increase the risk of developing post-diarrheal hemolytic uremic
syndrome (HUS) which poses many more symptoms and complications.
Apart from good supportive care as far as paying close attention to
hydration and nutritional needs, there is no specific therapy to treat the
symptoms of E. coli.
Since almost all cases of E. coli come from the direct contamination of
food to people, it is very important to be aware of the foods you eat and
how they are prepared.
The following methods are extremely important methods of
preventing illness and infection.
• Be careful to avoid cross contamination when preparing and
cooking food, especially if beef is being served.
• Wash your hands before and after eating. Before eating at a
restaurant, you may want to check the restaurant report rating for
hygiene to ensure they are rated high among surveyors.
• Make sure meats have a core temperature of at least 160 degrees
Fahrenheit for at least 15 seconds to ensure any contamination of
meat has been killed.
• Do not allow children to share bath water with anyone who has
diarrhea or the stomach flu. Keep any toddlers still in diapers out
of bodies of water such as swimming pools, lakes etc.
• Wear disposable gloves when changing diapers of any children
with diarrhea as children with E. coli may not have bloody diarrhea
but are still very infectious.
In the United States in 2003, contaminated food caused about 48
million illnesses, 128,000 hospitalizations and 3,000 deaths annually.
These are the results of all contaminations combined; luckily E. coli
contaminations have greatly decreased from previous years and have
since decreased significantly.
In the U.S., it is estimated that there are 73,000 cases of E. coli
each year annually, approximately 2,000 are hospitalized, and 60 people
died from infections from E. coli. Complications from this infection
account for less than 1% of all food borne illnesses. The most common
food borne illness is salmonella, followed by E. coli.
In Oregon, the average number of cases of E. coli increased from 83
in 2009 to 118 in 2010.
Food borne illnesses, including E. coli, have been
a major problem in our country for many years.
Although many cases on infected individuals
return to their normal healthy state after the
infection has run its course, there are some
cases in which patients succumb to the illness. It
is very important to continue education and
research on preventing and treating the spread
of E. coli. With the rise in infection over the last
few years, we need to continue efforts to treat
and prevent future encounters with this
particular bacteria. One area to begin in the area
of prevention involves the FDA. If the FDA
continues to take measures to ensure that
restaurants and food providers are taking every
measure possible to avoid contamination, we
will see a great decline in the abundance of
infections.
Marler, Bill. 2010, October 17. E. coli Lawyer and E. coli Attorney-18 years of experience.
http://www.ecoliblog.com/e-coli-legal-cases/
This website has some great references on statistics of E. coli and annual cases of the infection.
Davis, Charles Patrick. E. coli 0157:H7 (Escherichia coli 0157:H7 infection).
http://www.medicinenet.com/e_coli__0157h7/article.htm
This website provided a great description for E.coli bacteria as far as staining techniques, structures,
ability to survive in environments and provided some great pictures used in the slides as well.
Brain, Marshall. How Cells Work. http://science.howstuffworks.com/environmental/life/cellularmicroscopic/cell1.htm
This website had a great article describing the shape, size and structure of E. coli and also provided a
great comparison to human cells.
WebMD. 2010, June 14. E. Coli Infection- Topic Overview.
http://www.webmd.com/a-to-z-guides/e-coli-infection-topic-overview
WebMD has always been a source I use for medical information. This provided a general overview of E.
coli such as symptoms, treatment, prevention, as well as structure, function and pathophysiology.
MarlerClark. E. coli- E. coli bacteria: what are they, where did they come from, and why are some so
dangerous? http://www.about-ecoli.com/
This website providing a lot of information about methods of prevention and treatment of E. coli. It gives
a step by step list of different actions to take in regards to preventing future encounters with this
bacteria.