2. Overview of Topics
Definition Diagnosis
Description Treatment
Background Complications and Risk Factors
Microbial physiology Transmission
Group A Streptococci Prevention
Biochemistry Prognosis
Mode of Infection Living with the Disease
Symptoms Research
3. Definition
Flesh-eating disease is more properly called
Necrotizing fasciitis, a rare condition in
which bacteria destroy tissues underlying
the skin. This tissue death, called necrosis
or gangrene, spreads rapidly. This disease
can be fatal. The disease may also be called
synergistic gangrene, among other terms.
Definition from medical encyclopedia
4. Description
Although the term is technically incorrect,
flesh-eating disease is an appropriate
descriptor: the infection appears to devour
body tissue. The arms and legs are most
often affected, but the infection may appear
anywhere. For example, Fournier's
gangrene is a flesh-eating disease in which
the infection encompasses the external
genitalia.
5. Background
The disease was first discovered in 1783, in
France. Doctors noted that it occurred
sporadically throughout the 19th and 20th
centuries. The disease was usually restricted
to military hospitals, especially in war times.
However, there have been some outbreaks in
civilian populations. The disease appeared to
markedly decrease in frequency after WWII,
and reemerged worldwide in the 1980s.
6. Microbial Physiology
Flesh-eating disease is divided into two types.
Type I is caused by anaerobic species in
combination with facultative anaerobic
organisms such as streptococci (non-group A),
enterococci, and Gram-negative rods. Type II,
is called hemolytic streptococcal gangrene,
and is caused by group A streptococci; other
bacteria may or may not be present.
7. Microbial Physiology
Although Type I is far more common than
Type II, It isn’t nearly as dangerous. Most
deaths and serious infections that are
irreversible are caused by Type II infection.
8. Microbial Physiology
Necrotizing fasciitis can also be caused by
marine vibros(gram negative bacteria.) This
is usually an option only when a person has
been bit by a fish or shellfish. Necrotizing
fasciitis infections can also be caused by
fungus. These are rare and usually occur in
patients with weakened immune systems.
An example of a fungal infectant is
Mucormycosis.
9. Group A Streptococci
( Streptococcus pyogenes) viewed directly by Electron micrograph of
transmission electron microscopy (TEM). Chains of Streptococcus pyogens (96,000X)
streptococci are clearly evident. To remove cell
surface proteins, cells were treated with trypsin prior
to preparation and mounting. Strain: D471; M-type 6.
(6,500X)
Pictures Courtesy of “The Center of Disease Control”
10. Group A Streptococci
Group A streptococcus is a bacterium often
found in the throat and on the skin, people
may carry Group A streptococci(GAS) in
their throat or on their skin and have no
symptoms of illness at all. Most GAS
infections are relatively mild illnesses such
as "strep throat," or impetigo. On rare
occasions, these bacteria can cause other
severe and even life-threatening diseases.
Description of Group A Streptococci is from medical encyclopedia
11. Group A Streptococci
A picture of Streptococcus
pyogenes, part of the Group
A Streptococci family.
A micrograph with computer aided coloring
of Streptococcus pyogenes (25,000X)
Pictures Courtesy of “The Center of Disease Control”
12. Group A Streptococci
Severe, sometimes even life-threatening, GAS
disease occurs when bacteria get into parts of
the body where they usually are not found,
such as the muscle, lungs or the blood.
Invasive GAS infections occur when the
defenses of the person fail to keep the bacteria
out of the body.
13. Group A Streptococci cont…
This may occur when a person has sores, cuts
or other breaks in the skin that allow the
bacteria to get into the tissue, or when the
person’s ability to fight off the infection is
decreased because of chronic illness or an
illness that affects the immune system. This is
not the only factor, some virulent strains of
GAS are more likely to cause severe disease
than others.
14. The Biochemistry of the Disease
Usually the bacteria that cause Necrotizing
fasciitis releases enzymes and toxins that
spread rapidly through the body. Almost
every type of bacteria produce different
enzymes for example, Streptococci and
staphylococci produce hyaluronidase, which
destroys hyaluronic acid which is an essential
part of connective tissue.
15. The Biochemistry of the Disease
Multi-organ failure is also
caused by Necrotizing
fasciitis by the secretion
of a super antigen by a
certain strain of
streptococci causing
clones of T4 lymphocytes
which activate cytokines,
resulting in the production
of oxygen free radicals
and nitrous oxides.
Pictures courtesy of adam.com
16. Mode of Infection
In nearly every case, a
skin injury precedes the
disease. As bacteria grow
beneath the skin's
surface, they produce
toxins that degrade the
tissue. Almost any
puncture of the skin has
the potential of becoming
an infection.
Pictures courtesy of adam.com
18. Symptoms
• Swelling of the
infected area
• Black patches that are
filled with pus
Pictures courtesy of MD Challenger
19. Symptoms
• Discoloration in the
area of the infection
• It may appear
reddened, bronzed,
bruised, or purple
(purpuric)
• It progresses to
dusky, dark color
Pictures courtesy of adam.com
20. Symptoms
• There is visible dead
tissue
• The skin breaks and
open wounds form
• Fever
• The combination of
the symptoms results
in organ failure
Pictures courtesy of adam.com
21. Symptoms
Normal skin is held
tightly by proteins that
make up the connective
tissue that keep the
dermis, epidermis and
the muscle tightly
connected.
Pictures courtesy of adam.com
22. Symptoms
But when bacteria
invades the skin
through open wounds
and punctures of the
skin, they cause
devastating results by
“eating” the protein
and the connective
tissue.
Pictures courtesy of adam.com
23. Symptoms
If left untreated the Bacteria
will continue eating and
destroying the skin and
tissue beneath it until the
muscle is infected, when this
happens there is no hope of
saving the person unless the
infected area is surgically
removed to keep the bacteria
from spreading.
Pictures courtesy of adam.com
24. Symptoms
Comparing the uninfected skin to the early and advanced
forms of the disease:
Normal skin Early stage Advanced stage
Pictures courtesy of adam.com
25. Diagnosis
The appearance of the skin, paired with pain and
fever raises the possibility of flesh-eating disease.
An x ray, magnetic resonance imaging (MRI), or
computed tomography scans (CT scans) are very
helpful in diagnosing flesh eating bacteria.
Necrosis is evident during exploratory surgery,
during which samples are collected for bacterial
identification.
CT scan (computed tomography scan): Cross-sectional x-
rays of the body are compiled to create a three-dimensional
image of the body's internal structures.
26. Diagnosis
A picture of a slide
that was taken from an
infected site of a
patient, the
streptococci cells are
clearly seen. The
bacteria have been
stained with a Gram Streptococcus pyogens viewed under a light microscope (1000X)
Stain.
Pictures courtesy of the CDC
27. Diagnosis
• The best diagnosis is visual (i.e. symptoms)
• X-ray
• Magnetic resonance imaging
• Computed tomography (CT scans)
• Exploratory surgery
• Swab streaking of the infected area and
viewing microbes under microscope is
helpful in bacterial identification.
28. Diagnosis
X-ray, magnetic resonance imaging (MRI)
and computed tomography scans reveal
what is underlying the skin and are used to
show the feathery patterns in the tissue that
are caused by the accumulation of gas in
dying skin.
29. Diagnosis
Computed tomography
demonstrates soft tissue
gas collection from an
invasive Group A
Streptococci Bacteria.
Gas
Gas
vesicles
vesicles
Pictures courtesy of CDC
30. Treatment
Although a neutrophil can kill this bead-like string of Streptococcus pyogenes, this particular strain of
bacteria expresses streptolysin-s on its surface which causes the white cell to self-destruct. The white
cell's lytic granules, which are supposed to fire their antibacterial contents onto the bacteria, are
emptied into the white cell's cytoplasm instead, leading eventually to cell membrane lysis.
Treatment of the disease begins when the first bacterium
enter your body through a wound, but when dangerous
and rare strains of the disease enter your body, the
body’s defenses(macrophages) cannot fight off the
infection and antibiotics are needed.
Picture and description courtesy of www.cellsalive.com
31. Treatment
Rapid, aggressive medical treatment, specifically,
antibiotic therapy and surgical debridement, is
imperative. Antibiotics may be applied and
include penicillin, an aminoglycoside or third-
generation cephalosporin. Analgesics are
employed for pain control during surgical
debridement, in which dead tissue is stripped
away. After surgery, patients are rigorously
monitored for continued infection, shock, or other
complications. If available, hyperbaric oxygen
therapy can also be used.
32. Risk factors and Complications
Few people who ever come in contact with
GAS will develop invasive GAS disease.
Most people will have a throat or skin
infection, and some may have no symptoms
at all. Although healthy people can get
invasive GAS disease, people with chronic
illnesses like cancer, diabetes, and kidney
dialysis, and those who use medications
such as steroids are at a higher risk.
33. Transmission
While group A streptococcus is passed from
person to person in the air or through casual
contact as in strep throat, Necrotizing
fasciitis doesn’t transmit as easily. In order
to contract the disease from another person,
there has to be a cut or opening in the skin
and the opening coming in contact with the
open wound of the infected person.
34. Prevention
The spread of all types of GAS infection
can be reduced by good hand washing,
especially after coughing and sneezing and
before preparing foods or eating. Persons
with sore throats should be seen by a doctor
who can perform tests to find out whether
the illness is strep throat.
35. Prevention
All wounds should be kept clean and
watched for possible signs of infection such
as redness, swelling, drainage, and pain at
the wound site. A person with signs of an
infected wound, especially if fever occurs,
should seek medical care.
36. Prevention
It is not necessary for all persons exposed to
someone with an invasive Group A Strep
infection (i.e. Necrotizing fasciitis or strep
toxic shock syndrome) to receive antibiotic
therapy to prevent infection. However, in
certain circumstances, antibiotic therapy
may be appropriate. That decision should be
made after consulting with your doctor.
37. Prognosis
Flesh-eating disease has a fatality rate of about
30%. Diabetes, arteriosclerosis,
immunosuppressant, kidney disease, malnutrition,
and obesity are connected with a poor prognosis.
Older individuals and intravenous drug users may
also be at higher risk. The infection site also has a
role at how serious the infection is. Survivors may
require plastic surgery and may have to contend
with permanent physical disability and
psychological adjustment.
38. Living with the Disease
Most people who survived the horrible
ordeal with the flesh eating bacteria have
missing limbs and body parts. Often people
choose to cut extra skin from such places as
their thighs to cover the missing patches of
skin cut off to limit the infection site. Some
people had plastic surgery to repair their
skin in instances where the infection
occurred on their faces.
40. Living with the Disease
A patient out of the surgery room
after a flesh eating bacteria disease
infected his leg.
An arm infection.
Pictures courtesy of e-medicine
41. Research
Researchers do not know why the normally mild
Group A Streptococcus bacteria sometimes
becomes a more serious threat. They are unsure
exactly why Group A Streptococcus may cause
minor infections, such as strep throat, in some
people, and very serious infections, such as toxic
shock syndrome or necrotizing fasciitis, in others.
Bacteria have many different characteristics that
can change over generations, keeping in mind that
a generation for bacteria can be as short as 20
minutes.
42. Research
Many scientists believe the bacteria makes
proteins that cause the body's immune system to
destroy both the bacteria and body, in addition to
proteins that destroy tissue directly. There is no
vaccine available to prevent group A streptococcal
infections. Since there are many types of group A
streptococci, one of the biggest problems facing
researchers has been how to make one vaccine
against all the different types of bacteria.
43. Thank you for listening to our presentation.
For more information about Group A
Streptococci and the diseases it causes visit:
www.emedicine.com or call the the Center for
Disease and Control at 1-800-311-3435.
Pictures and statistical information were used from:
www.adam.com www.CDC.gov
www.nnff.org www.emedicine.com
www.emergency.com/strep-a.html-6k
