Bacterial Toxins endotoxin exotoxinO- antigen , core polysaccharide and lipid A. Properties of bacterial endotoxin Properties of bacterial exotoxin Toxoid Types of exotoxins A-B toxin Super-antigen Membrain disrupting How Our Body Eliminates Toxins

1. SUBMITTED BY-
DEBIPRASAD KANTAL
FS-10/14
B.F.SC-3RD YEAR -2ND SEM
SUBMITTED TO –
PROF. T.J.ABRAHAM
DEPT OF AAH

2. Toxins
• Are virulence factor of most of bacteria and one of the major
cause of tissue damage.
• Poisonous substances produced by microorganism
• It may be protein lipid or any tissue
Bacterial
Toxins
endotoxin exotoxin

3. Endotoxin
• LPS of Gram negative cell has three
parts:- O- antigen , core polysaccharide
and lipid A.
• Released usually when the cell is lysed
but can also be released during
vegetative growth.
• Has same chemical composition in
almost all bacteria and has same toxic
effect ( no matter which bacteria
produce it).
• Encoded by chromosomal gene.

4. Properties of bacterial endotoxin
1. Integral part of the cell wall of Gram-negative bacteria. Released on
bacterial death and in part during growth. Release is not required for
biologic activity.
2. Formed only by Gram-negative bacteria
3. Lipopolysaccharides. Lipid A portion is responsible for toxicity.
4. No specific receptor.
5. Moderately toxic. Fatal to animals in large doses.
6. Relatively heat stable. Toxicity is not destroyed above 60°C for hours.
7. Weakly antigenic. Antibodies are protective.
8. Not converted to toxoid.
9. Synthesis directed by chromosomal genes.
10. Usually produce fever in the host by release of interleukin-1 and other
mediators..

6. Exotoxin
• Are most powerful and active in small quantities.
• Either secreted by organism or leak into the surrounding fluid after
lysis of bacterial cell.
• Gene for exotoxin may be present on chromosome or plasmid or
bacteriophage DNA.

7. Properties of bacterial exotoxin
1.Excreted by living cells
2. Produced by Gram-positive and Gram-negative bacteria
3. Polypeptides
4. Usually bind to specific receptors on cells
5. Highly toxic. Fatal to animals in very small doses
6. Relatively heat labile. Toxicity destroyed over 60°C
7. Highly antigenic. Stimulate formation of antitoxin. Antitoxin neutralizes
the toxin
8. Converted to toxoid by formalin. Toxoid is nontoxic but antigenic. Toxoids
are used to immunize, e.g. tetanus toxoid
9. Usually controlled by extra-chromosomal genes, e.g. plasmids, phage
gene
10. Usually do not produce fever in the host.

8. Toxoid
• Toxoid is modified exotoxin. An exotoxin has
two main properties :
(1) toxicity, and
(2) antigenicity.
• In toxoid, the toxicity of the toxin is destroyed
but its antigenicity is preserved. As such
toxoids e.g. diphtheria toxoid, tetanus toxoid
can be safely used for vaccines. Toxins can be
converted to toxoid by different methods e.g.
formalin treatment.

9. Types of exotoxins
1. A-B toxin
2. Super-antigen
3. Membrain disrupting

10. A-B toxin
10
• Have two
components
(A and B)
• B components
binds to
specific cell
receptor and
facilitate the
internalization
of A.
• Component A
is active (toxic)
component.

12. Super-antigen
Some bacteria directly inject exotoxin
into target cell via needle like
projections called injectosome.
Also called type III secretory system.
Bacteria having type III secretory
system are more virulent.

14. Membrane-disrupting toxins
• Membrane-disrupting toxins lyse host cells by disrupting plasma
membranes
• Leukocidins—kill phagocytic leukocytes
• Hemolysins—kill erythrocytes by forming protein channels
• Streptolysins—hemolysins produced by streptococci

16. How Our Body Eliminates Toxins
1. Liver :
The liver has a critical role in the processing of toxins, including some medications
(such as acetaminophen) and alcohol.
The liver contains many enzymes, which are special proteins that can enable
chemical reactions to take place in the body.
 Some of the enzymes in the liver are used for toxin processing. Blood from the
body flows through the liver where toxins in the blood can be processed.
Some of the enzymes work to inactivate toxins to keep them from damaging the
body.
Enzymes can also break down compounds in the blood or modify them so that
they stay dissolved and can then be excreted, via the kidneys or other methods.

17. How Our Body Eliminates Toxins
1. Liver :
2. Kidneys :
• The kidneys are one of the primary ways in which the body is able to eliminate
toxins and waste products from the blood.
• The kidney contains many small structures called glomeruli, which essentially
work to filter substances (such as toxins and waste products) out of the blood,
where they are concentrated into the urine, which is then excreted from the body
via the bladder and the urethra.
• Some toxins don't get filtered out by the glomeruli and are instead actively
secreted by the kidneys into the urine. Regardless, the kidneys ability to secrete
waste products and toxins into the urine is one of the primary ways in which
toxins are eliminated from the body

18. How Our Body Eliminates Toxins
1. Liver :
2. Kidneys :
3. Sweat :
• Another way in which toxins can be eliminated from the body is via sweat.
• Some toxins and waste products in the blood are able to diffuse into the sweat
glands.
• As a result, when the body excretes sweat (in order to cool down), some toxins
are excreted as well.
• Sweating is normally not able to process nearly as many toxins as urine
production by the kidneys, but it provides an auxiliary method of toxin
elimination.

19. How Our Body Eliminates Toxins
1. Liver :
2. Kidneys :
3. Sweat :
4. Gut:
• We all know that we get rid of most of our waste through our bowels.
If digestive system is not working properly, it can’t get rid of
unwanted waste and toxins properly.
• Our body empties many toxins into our excrement, but if it is sitting
in the bowel too long (i.E. You are constipated) — it can get
reabsorbed and go through our detox systems again — increasing
their workload and making them less effective.

20. Bacteria
Responsible
Description Types of Foods Symptoms Cause
Temperture
Sensitivity
Staphylococcus
aureus
Produces a
heat-stable
toxin
Meat and
seafood salads,
sandwich
spreads and
high salt foods.
Nausea, vomiting and
diarrhea within 4 to 6
hours. No fever.
Poor personal
hygiene and
subsequent
temperature abuse.
No growth below 40°
F. Bacteria are
destroyed by normal
cooking but toxin is
heat-stable.
Salmonella
Produces an
intestinal
infection
High protein
foods – meat,
poultry, fish
and eggs.
Diarrhea nausea,
chills, vomiting and
fever within 12 to 24
hours.
Contamination of
ready-to-eat foods,
insufficient cooking
and recontamination
of cooked foods.
No growth below 40°
F. Bacteria are
destroyed by normal
cooking.
Clostridium
perfringens
Produces a
spore and
prefers low
oxygen
atmosphere.
Live cells must
be ingested.
Meat and
poultry dishes,
sauces and
gravies.
Cramps and diarrhea
within 12 to 24 hours.
No vomiting or fever.
Improper
temperature control
of hot foods, and
recontamination.
No growth below 40
degrees F. Bacteria
are killed by normal
cooking but a heat-
stable spore can
survive.

21. Bacteria
Responsible
Description
Types of
Foods
Symptoms Cause Temperture Sensitivity
Clostridium
botulinum
Produces a spore
and requires a low
oxygen
atmosphere.
Produces a heat-
sensitive toxin
Home-
canned
foods.
Blurred vision,
respiratory
distress and
possible DEATH.
Improper
methods of
home-processing
foods.
Type E and Type B can grow
at 38° F. Bacteria destroyed by
cooking and the toxin is
destroyed by boiling for 5 to 10
minutes. Heat-resistant spore
can survive.
Vibrio
parahaemolyticus
Requires salt for
growth.
Raw and
cooked
seafood.
Diarrhea, cramps,
vomiting,
headache and
fever within 12 to
24 hours.
Recontamination
of cooked foods
or eating raw
seafood.
No growth below 40° F.
Bacteria killed by normal
cooking.
Bacillus cereus
Produces a spore
and grows in
normal oxygen
atmosphere.
Starchy
food.
Mild case of
diarrhea and
some nausea
within 12 to 24
hours.
Improper holding
and storage
temperatures
after cooking.
No growth below 40° F.
Bacteria killed by normal
cooking, but heat-resistant
spore can survive.
E. coli
Can produce
toxins that are
heat stable
Meat
and
cheeses.
Diarrhea,
abdominal
cramps, no fever.
Inadequate
cooking.
Recontamination
of product.
Organisms can be controlled by
heating. Can grow at refrigeration
temperatures.

22. Prevention
• Normally a large number of food-poisoning bacteria must be present
to cause illness. Poor personal hygiene, improper cleaning of storage
and preparation areas and unclean utensils cause contamination of
raw and cooked foods. Mishandling of raw and cooked foods allows
bacteria to grow Therefore, illness can be prevented by
1. controlling the initial number of bacteria present,
2. preventing the small number from growing
3. destroying the bacteria by proper cooking and
4. avoiding re-contamination.

23. • Food borne illness is an ever-present threat that can be prevented with proper care and handling of
food products.
• Chemicals, heavy metals, parasites, fungi, viruses and bacteria can cause food borne illness.
Bacteria related food poisoning is the most common, but fewer than 20 of the many thousands of
different bacteria actually are the culprits. More than 90 percent of the cases of food poisoning each
year are caused by Staphylococcus aureus, Salmonella, Clostridium perfringens, Campylobacter,
Listeria monocytogenes, Vibrio parahaemolyticus, Bacillus cereus, and Entero-
pathogenic Escherichia coli. These bacteria are commonly found on many raw foods.
• The temperature range in which most bacteria grow is between 40˚F (5˚C) and 140˚F (60˚C). Raw
and cooked foods should not be kept in this danger zone any longer than absolutely necessary.
Undercooking or improper processing of home-canned foods can cause very serious food poisoning

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