Normal Flora Flashcards
What are normal flora
These are mixture of micro-organisms regularly found at any anatomical site on or within the body of a healthy person.
List the estimation of normal flora in the human body
10^12 on the skin
10^10 on the mouth
10^14 in the gastrointestinal tract
Importance of normal flora
They constitute a protective host defense mechanism by occupying ecological niche
Meaning they occupy specific spaces in the body and if any other bacteria tries to come there they destroy it
Factors affecting normal flora
Genetics
Age
Sex
Stress
Nutrition
Diet
Antibiotics and other drugs
Normal flora can be divided into two namely
Resident flora: microbes always present on or within the body
Transient Flora: Microbes that live in or in the body for a period of time ( hours,days, weeks,months) then move on or die off
What are resident flora
Microbes that are always present on or within body
What are transient flora
Microbes that live in or on the body for a period of time (hours, days, weeks, months) then move on or die off
Where is Corynebacterium diphtheriae found
Throat
Where is neisseria gonorrhoeoe found
Urogenital tract
Where is staphylococcus mutans found
Tooth surfaces
Where is staphylococcus salivarius found
Tongue surface
Where is E. coli found
Small intestine epithelium
Staphylococcus aureus
Nasal membrane
Staphylococcus epidermidis
Skin
Normal flora of the skin list them
Staphylococcus epidermidis
Micrococcus sp
Coryne bacterium sp
Mycobacterium smegmatis
Normal flora of the conjuctiva
1) staphylococcus epidermidis
2) Coryne bacterium sp
3) propionibacterium acnes
4) staphylococcus aureus
5) Viridans streptococci
6) Neisseria app
7) Hemophilus influenzae
Normal flora of the respiratory tract
The nostrils
1) staphylococcus epidermidis
2) Corynebacteria spp
3) staphylococcus aureus
4) Neissera spp
5) hemophilus spp
6) streptococcus pneumonia
Normal flora of the respiratory tract
Upper respiratory tract. (Nasopharynx)
Non hemolytic streptococci
Alpha hemolytic streptococci
Neisseria spp
Streptococcus pneumonia
Streptococcus pyogens
Hemophilus influenzae
Neisseria Meningitidis
Normal flora of the lower respiratory tract include:
Hemophilus influenzae
Streptococcus pneumonia
Normal flora of the human oral cavity
Viridans streptococci
Lactobacilli
Staphylococcus aureus and epidermidis
Corynebacterium sp
Bacteroides sp
Streptococcus sanguis (dental plaque)
Streptococcus mutans ( dental plaque)
Actinomyces sp
Normal flora of the ears
1) staphylococcus epidermidis
2) staphylococcus aureus
3) Corynebacterium sp
Normal flora of the Urogenital tract
Anterior urethra
Staphylococcus epidermidis
Enterococcus faecalis
Alpha hemolytic streptococci
Some enteric bacteria (e.g E. coli, proteus sp)
Corynebacterium sp
Acinetobacter sp
Mycoplasma sp
Candida sp
Mycobacterium smegmatis
Normal flora of the vagina
1) Corynebacterium sp.
2. Staphylococci
3. Non-pyogenic streptococci
4. Escherichia coli
5. Lactobacillus acidophilus*
6. Flavobacterium sp.
7. Clostridium sp.
8. Viridans streptococci
9. Other Enterobacteria
Normal Flora of the Gastrointestinal Tract (GIT):
•In breast-fed infants :
- Bifido bacteria account for more than 90% of the total intestinal bacteria.
- Enterobacteriaceae
- Enterococci
- Bacteroides
- Staphylococci
- Lactobacilli
- Clostridia
Normal Flora of the Gastrointestinal Tract (GIT):
•In bottle-fed infants:
Bifido bacteria is joined by ( although no longer predominant)
Enterics
Bacteroides
Enterococci
Lactobacillus
Clostridium
Normal Flora of the Gastrointestinal Tract (GIT):
In the upper GIT of adult humans
Mainly acid tolerant lactobacilli e.g helicobacter pilori
Normal Flora of the Gastrointestinal Tract (GIT):
Proximal small intestine:
1) Lactobacilli
2. Enterococcus faecalis
3. Coliforms
4. Bacteroides
The flora of the large intestine (colon)
1) Enterococci
2.Clostridia
3.Lactobacilli
4.Bacteroides
5.Bifidobacterium (Bifidobacterium bifidum)
6.Escherichia coli
7.Methanogenic bacteria
8.Viridans streptococci
9.Staphylococcus sp.
10.Proteus sp.
11.Candida albicans (Yeast)
12.Mycoplama sp.
THE ROLE/ BENEFITS OF THE NORMAL FLORA:
1) The normal flora synthesize and excrete vitamins in excess of their own needs, which can be absorbed as nutrients by the host.
2) The normal flora prevent colonization by pathogens by competing for attachment sites or for essential nutrients
3) The normal flora may antagonize other bacteria
4) The normal flora stimulates the development of certain tissues,
5) The normal flora stimulates the production of “cross-reactive antibodies’’.
The caecum of germ-free animals is ___________, ___________, and __________, compared to that organ in conventional animals.
Enlarged
Thin walled and
Fluid filled
What tissues do normal flora stimulate the development of
Caecum in animals
Payers patches in the GI tract
What are sterile tissues
The internal tissues of healthy humans that are normally free of microorganisms
Examples of sterile tissues
Blood
Brain
Muscle
CSF
NATURAL MICROBIAL HABITATS
Soil
Water
Air
Animal and animal products
Define Mutualistic/ mutualism:
Both organisms benefit “beneficial interaction”
Define Commensalistic/ commensalism
One organism benefits the other is neither helped nor harmed
Define Opportunistic
Under normal conditions, microbe does not cause disease, but if conditions become conducive , it can cause disease. (Immuno-compromised or immuno-suppressed conditions)
List and example of a mutualistic bacteria
Escherichia coli :
–Synthesizes Vitamin K & B complex Vitamins
–In return, we provide a warm, moist nutrient rich environment for Escherichia coli
Example of commentialistic bacteria
We have no Commensalistic relationships with Bacteria
•If Bacteria are in or on our body, they are either helping us (Microbial Antagonism) or harming us.
Example of opportunistic bacteria
Escherichia coli - normally in our digestive tract where it causes no problems, but if it gets into the urinary tract it can become pathogenic.
•Staphylococcus aureus – commonly found in the upper respiratory tract, but if it gets into a wound or a burn it can become pathogenic
What are probiotics
-Oral administration of living organisms to promote health
–Species specific: adherence and growth (tropism)
What are prebiotics
Non-digestible food that stimulates growth or activity of GI microbiota, especially bifidobacteria and lactobacillus bacteria
–Typically a carbohydrate: soluble fiber
