Microbiology Bio 127 Microbial Interactions with Humans (normal flora)
Microbial Flora of the Human Body - Karachi King's School ... · Normal Microbial Flora 1. Resident...
Transcript of Microbial Flora of the Human Body - Karachi King's School ... · Normal Microbial Flora 1. Resident...
Ramesh kumar
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Normal Flora Definition
Normal flora is themixture ofmicroorganisms(bacteria and fungi) thatare regularly found atany anatomical site ofhuman body.
DefinitionNormal flora is themixture ofmicroorganisms(bacteria and fungi) thatare regularly found atany anatomical site ofhuman body.
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Symbioticrelationship
Mutualistic Communalistic Opportunistic
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Symbiotic Relationship 1. Mutualistic Both organisms benefit – “mutually beneficial”
2. Commensalistic One organism benefits, the other is neither helped nor
harmed
3. Opportunistic Under normal conditions, microbe does not cause
disease, but if conditions become conducive , it cancause disease
1. Mutualistic Both organisms benefit – “mutually beneficial”
2. Commensalistic One organism benefits, the other is neither helped nor
harmed
3. Opportunistic Under normal conditions, microbe does not cause
disease, but if conditions become conducive , it cancause disease
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Mutualistic Escherichia coli Synthesizes Vitamin K & B complex Vitamins
In return, we provide a warm, moist nutrient richenvironment for E. coli
Escherichia coli Synthesizes Vitamin K & B complex Vitamins
In return, we provide a warm, moist nutrient richenvironment for E. coli
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CommensalisticWe have no Commensalistic relationships with Bacteria
If Bacteria are in or on our body, they are either helpingus (Microbial Antagonism) or harming us.
We have no Commensalistic relationships with Bacteria
If Bacteria are in or on our body, they are either helpingus (Microbial Antagonism) or harming us.
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Opportunistic Escherichia coli - normally in our digestive tract where
it causes no problems, but if it gets into the urinarytract it can become pathogenic.
Staphylococcus aureus – commonly found in the upperrespiratory tract, but if it gets into a wound or a burn itcan become pathogenic
Escherichia coli - normally in our digestive tract whereit causes no problems, but if it gets into the urinarytract it can become pathogenic.
Staphylococcus aureus – commonly found in the upperrespiratory tract, but if it gets into a wound or a burn itcan become pathogenic
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The Three Types of SymbioticRelationships
Table 14.1 9
Types ofnormal flora
ResidentFlora
TransientFlora
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Normal Microbial Flora 1. Resident Flora Microbes that are always present
2. Transient Flora Microbes that live in or on your body for a period of time
(hours, days, weeks, months) then move on or die off
1. Resident Flora Microbes that are always present
2. Transient Flora Microbes that live in or on your body for a period of time
(hours, days, weeks, months) then move on or die off
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Transient Microbiota Remain in the body for only hours to
months before disappearing
Found in the same regions as residentmicrobiota
Cannot persist in the body…because… Competition from other microorganisms Elimination by the body’s defenses cells Chemical or physical changes in the body
Remain in the body for only hours tomonths before disappearing
Found in the same regions as residentmicrobiota
Cannot persist in the body…because… Competition from other microorganisms Elimination by the body’s defenses cells Chemical or physical changes in the body
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Sterile tissuesIn a healthy human, the
internal tissues such as: blood brain muscle cerbrospinal fluid (csf.)
are normally free ofmicroorganisms.
Normal Flora
Sterile tissuesIn a healthy human, the
internal tissues such as: blood brain muscle cerbrospinal fluid (csf.)
are normally free ofmicroorganisms.
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Normal Flora Skin Eyes (i.e.Cunjunctiva) Nose (i.e. Respiratory
tract) Mouth (i.e Human Oral
Cavity) Ears Urogenetal tract Elementry tract
Skin Eyes (i.e.Cunjunctiva) Nose (i.e. Respiratory
tract) Mouth (i.e Human Oral
Cavity) Ears Urogenetal tract Elementry tract
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Normal Flora Resident flora Acquired rapidly during
& after birth
Resident flora Acquired rapidly during
& after birth
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Normal Flora Resident flora
Reflects age of person
Resident flora
Reflects age of person
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Normal FloraResident flora
Changes continuously throughout life
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Normal Flora Resident flora Reflects nutrition of
person
Resident flora Reflects nutrition of
person
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Normal Flora Resident flora Reflects genetics of
person
Resident flora Reflects genetics of
person
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Normal Flora
Resident floraReflects environment ofperson
Resident floraReflects environment ofperson
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Resident flora Reflects sex of
person
Normal Flora
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1. They constitute aprotective hostdefense mechanismby occupyingecological niches.
Importance of TheNormal Flora(Advantages)
1. They constitute aprotective hostdefense mechanismby occupyingecological niches.
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Importance of The Normal Flora(Advantages)
2. They produce vitamin Band vitamin K inintestine.
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Importance of The Normal Flora(Advantages)
3.The oral floracontribute toimmunity by inducinglow levels ofcirculating andsecretory antibodiesthat may cross reactwith pathogens.
3.The oral floracontribute toimmunity by inducinglow levels ofcirculating andsecretory antibodiesthat may cross reactwith pathogens.
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Importance of The Normal Flora(Advantages)
4.The oral bacteria floraexert microbialantagonism againstnonindigenous speciesby production ofinhibitory fatty acids,peroxides, bacteriocins,etc.
4.The oral bacteria floraexert microbialantagonism againstnonindigenous speciesby production ofinhibitory fatty acids,peroxides, bacteriocins,etc.
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Importance of The Normal Flora(Advantages)
5. The normal flora mayantagonize otherbacteria through theproduction ofsubstances which inhibitor kill nonindigenousspecies.
5. The normal flora mayantagonize otherbacteria through theproduction ofsubstances which inhibitor kill nonindigenousspecies.
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Importance of The Normal Flora(Disadvantages)1. They can cause disease in
the following:a) When individualsbecomeimmunocompromised.b) When they change theirusual anatomic location.
1. They can cause disease inthe following:a) When individualsbecomeimmunocompromised.b) When they change theirusual anatomic location.
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