Oral Ecology Flashcards
What is the life cycle of pathogens?
– Enter
– Attach
– Colonise
– Evade host immunity
– Produce harmful proteins
– Disseminate
– Release from host
What are koch’s postulates regarding germ diseases?
- 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
What is the holobiont theory?
hosts and microorgaanisms have mutual adaptation and functional integration that allows them to co-evolve
What is the human microbiome?
- The human microbiome refers to all of the microorganisms that live in and on your body, including your mouth, gut and your skin.
- Human cells are outnumbered ten to one by microbes in our bodies.
How do we aquire our resident flora from infancy?
2 ways
- 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 colonizing the intestines changes depending on whether the baby is bottle- or breast-fed
What do families have similar?
microbiomes
What are the benefits of the normal flora?
- Synthesize vitamines (K, and B12)
- Prevent colonization by pathogens
- Antagonize other bacteria
- Stimulate tissue development
- Stimulate antibody production
What did mice raised in a germ-free environment display?
– Decreased nutrient absorption
– Less developed intestines
– Vitamin deficiency
– Underdeveloped immune system
– Heighted sensitivity to pathogens
What are the major barriers for microbes entering the gut?
- Low pH
- Saliva and Bile
- Immune system
- Finding a place to attach to intestinal wall
- Surviving a widely varied diet
What are the microbes that bypass the barriers able to do?
- Gut flora perform regular tasks of digestion, vitamin production, many others
- Gene transfer between the myriad of species in the gut can generate new combinations of drug resistant “superbugs”
What varies in the GI microbiome from person to person?
The number and amount of the many different microbes can vary greatly from person to person.
How is methane gas produced in the GI?
Certain gut bacteria like Bacteroides ferment carbohydrates, releasing hydrogen gas (H2) and carbon dioxide (CO2).
Other archaea like Methanobrevibacter then consume the hydrogen gas and produce methane gas (CH4), which is expelled as flatulence.
What do fecal transplants result in?
assited colonisation = more healthy biome
What does the obese gut microbiome contain more of?
Obese gut microbiome contains more genes predicted to harvest energy from polysaccharides
What common therapeutics influence the microbiome and how?
Antibiotics
Kills infectious bacteria but also disrupts natural flora. Can result in yeast infections, digestive problems, etc.
Chemotherapy drugs
Gut flora has been shown to modify some drugs during metabolism. This causes many side effects, including upset stomach.
