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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Thanks yourThanks your

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