Microbial Ecology of the Mouth Flashcards
what is the idea behind the human microbiome
Idea is that on your body there are lots and lots of living organisms everywhere
what is a microbe
a tiny living organism, such as bacterium, fungus, protozoan, or virus
what is a microbiome
collectively all the microbes in the human body; a community of microbes
Changes to the microbiome tend to related to changes from health to disease
what is a biofilm
a community of microbes that live together on a surface
how are microbes ubiquitous
There are millions of microbes per square inch on your body
Thousands of different species on the skin alone
Some thrive on dry patches on the elbow, others thrive in moist environments like the armpit
It is estimated that there are more microbes in your intestine than there are human cells in your body
is there more bacterial cells than body cells in the human body?
Bacterial cells outnumber your body cells 10:1 and comprise up to 4-6 pounds of your body mass
what is included in a microbiome
A microbiome includes all the micro-organisms in a particular ecosystem
what are the different ways in which microbiome can be used
The term is sometimes used to describe the community of micro-organisms in a particular place
Sometimes it is used to describe the total of the genetic material of the microorganisms in a particular ecosystem
where do the microbes come from in the body
Some microbes are native, normally found in the body
Some microbes are introduced, suddenly arriving at a new residence in the body
how do we acquire our resident flora?
- From delivery
- The gut flora of vaginally-delivered babies differs from babies delivered by C-section
- The vaginal microbial community of pregnant women contains bacteria involved in digesting milk (lactobacillus) - From feeding
- The nature of the flora colonising the intestines changes depending on whether the baby is bottle or breast fed
- The oral cavity, skin, GI tract, respiratory, and urogenital system all continue to be colonised as contact with other humans continues)
what are the benefits of normal flora
- Synthesise and excrete vitamins
- Vitamin K
- Vitamin B12 - Prevent colonisation by pathogens
- Competing for attachment sites or for essential nutrients - May antagonise other bacteria
- The production of substances which inhibitor kill non-indigenous species (nonspecific fatty acids, peroxides, bacteriocins - Stimulate the development of certain tissues
- Ie intestines
- certain lymphatic tissues
- Capillary density - Stimulate the product 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
what does a faecal transplant do
Faecal transplant = assisted colonisation
Gut flora similar to donor within 14 days
Big change
Faecal transplants work - completely change the microbiome
what prevents microbes from surviving within the oral cavity
- saliva
- pH
- temperature
- immune system
- brushing and flossing teeth clears some built up biofilm
- oral antibiotics inhibit growth
what does symbiosis of microbes that are able to survive in the conditions of the oral cavity do
form an elaborate scaffold that lives on the tooth enamel and at the interface with the gums.
It forms a barrier for incoming bacteria
what is Koch’s Postulates
The germ theory of disease
• 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
• No absolute way to demonstrate Koch’s Postulates in the oral cavity
