Oral ecology of the mouth

Question 1

What is the human microbiome

Answer 1

collectively all the microbes in the human body; a community of microbes
also used to describe the total of the genetic material of the microorganisms in a particular ecosystem

Question 2

what is a biofilm

Answer 2

a community of microbes that live together on a surface

Question 3

what is a microbe

Answer 3

tiny living organism, such as bacterium, fungus, protozoan, or virus

Question 4

Microbes can be native or introduced what does this mean

Answer 4

native - normally found in the body

introduced - suddenly arriving at a new residence in the body

Question 5

How do we acquire our resident flora?

Answer 5

1. From delivery: The gut flora of vaginally-delivered babies differs from babies delivered by C-section
2. From feeding: The nature of the flora colonizing the intestines changes depending on whether the baby is bottle- or breast-fed

The oral cavity, skin, gastrointestinal tract, respiratory, and urogenital system all continue to be colonized as contact with other humans continues)

Question 6

What are the benefits of the normal flora?

Answer 6

1. Synthesize and excrete vitamins
   - Vitamin K and Vitamin B12
2. Prevent colonization by pathogens
   - competing for attachment sites or for essential nutrients
3. May antagonize other bacteria
   - the production of substances which inhibit or kill non-indigenous species (nonspecific fatty acids, peroxides, bacteriocins).
4. Stimulate the development of certain tissues
   - i.e., intestines, certain lymphatic tissues, capillary density
5. Stimulate the production of cross-reactive antibodies.
   - Low levels of antibodies produced against components of the normal flora are known to cross react with certain related pathogens, and thereby prevent infection or invasion.

Question 7

Functions of microbiome

Answer 7

• modulation of bone-mass density
• promotion of fat storage
• promotion of angiogenesis
• development and training of the immune system
• biosynthesis of vitamins and amino acids
• metabolism of therapeutics
• modification of the nervous system
• breaking down food compounds
• resistance to pathogens
• protection against epithelial injury

Question 8

What treatment can treat chronic diarrhea and potentially obesity

Answer 8

fecal transplant

Question 9

In the mouth, what prevents many microbes from surviving

Answer 9

saliva, pH, temperature, immune system

Symbiosis of the oral microbes that are able to survive these conditions form an elaborate scaffold that lives on the tooth enamel and at the interface with the gums. It forms a barrier for incoming bacteria.

Question 10

how can we get rid of biofilms in the mouth

Answer 10

brushing and flossing

oral antibiotics

Question 11

What are the 4 koch’s postulates

Answer 11

The microbe must be present in every case of the disease

The microbe must be isolated from the diseased host and grown in pure culture

The disease must be reproduced when a pure culture is introduced into a susceptible host

The microbe must be recovered from an experimentally infected host

Question 12

What are the factors which may cause dysbiosis of the oral microbiome

Answer 12

Major ecological pressure and altered competitiveness

• genetic differences
• activity of salivary proteins
• salivary flow rates
• innate/adaptive immune factors
• oral hygiene
• diet
• smoking
• antibiotics/antimicrobial agents
• diseases e.g. diabetes

Question 13

What impact do antibiotics have on the gut microbiota

Answer 13

• depletion of bacterial diversity
• altered gene expression, protein activity and overall metabolism
• selection for intrinsically resistant bacteria
• selection for new mutations and gene transfers conferring resistance
• increased susceptibility to infections
• compromised immune homeostasis
• accumulation of antibiotic resistances
• deregulated metabolism