Relationships L1 Flashcards
What is a human microbiome?
A community of microorganisms (such as bacteria, fungi, and vuruses) that inhabit a particular environment
Microbiome vary with…
The type of tissue condition
pH, moisture, type of microbes present
Can microbiome cause diseases?
Can cause disease if reach in abnormal location or if epithelial defense is impaired
Generally non-pathogenic
Why should a microbiome be studied?
- Determine what microorganisms are living in an environment
- Allows comparison of microbiome between healthy and unhealthy people
- Investigate if changing microbiome can make an individual healthy
- determine if microbiome
Explain the contributions of human microbiota to human health
- Production of antimicrobials which controls growth of pathogenic bacteria
- Occupy receptor sites which could be used by potential pathogens
- Digestion
- Vitamin production(vitamin K/B)
- Modulation of the immune system
What are risks associated with the microbiota?
Opportunistic pathogens
- surface breach allows bacterial entry
- immunocompromised hosts
What are the general host defenses?
- Physical barriers
- skin
- keratin
- skin
- chemical barriers to infection
- Acidic pH: stomach, skin, vagina
Give the functions of mucous membranes
In throat, mouth
- trap, destroy pathogens
- Mucous layers sheds off
- Cilia, remove microbe from lungs
Give some examples of sterile sites in the body
The heart
The brain
Erythrocytes/blood
Kidneys
Give factors affecting human microbiome
- diet
- medications
- infections
- genetics
-infant feeding(breast vs formula)
Less bacterial diversity selected bacteria which metabolizes carbohydrates
-method of delivery
How does method of delivery afffect the hospital?
Method of delivery( vaginal vs C-section)
C-section: dominated by Enterococcus and klebsiella, which circulate in hospitals
How do human microbes adjust?
- interact with human immune system
- interact with other bacterial species
- Adjust to environmental factors
- pH
- temperature
- salinity
- oxygen availability
- water availability
-Produceenzymes which increase survival
What is the body’s largest organ?
The skin
The skin is colonized by ….
Diverse microorganisms
What is the function of skin?
- A physical barrier
- protecting our bodies from potential assault by foreign organisms or toxic substances
- difficult to colonize
- Dry, acidic, protective oils
-Disease involvement:
Explain how the skin was involved in diseases?
Propionibacterium acnes
- fatty acid induce inflammation - inflamed sebaceous gland - causes acne
When is the skin sterile?
Skin is sterile in utero, but colonization occurs immediately after birth
What is the colonization of skin driven by?
- Endogenous host factors e.g. sex, age
- Exogenous environmental factors e.g. climate
What are the factors contributing to variation in the skin microbbiome?
- Host physiology - sex, age and site
- Environment- climate, geographical location
- Host genotype- susceptibility genes such as filaggrin
- Lifestyle- occupation, hygiene
- Pathobiology- underlying conditions such as diabetes
What are the requirements of Staphylococcus aureus ( S. Aureus) colonization?
- Attachment
- Secrete bacterial products that kill other microorganisms
- Release of proteins which help evade the immune system
- Adjust to local environmental conditions
- osmolarity
- pH
- salt concentration
- wet and dry conditions
What is the second largest microbial community in humans?
Oral microbiome
What body parts comprise the oral microbiome?
The teeth, tongue, cheeks, gingival sulcus, tonsils, hard palate and soft palate provide a rich environment in which microorganisms can flourish
What factors contribute to microbial life in the oral microbiome?
- The normal temperature of the oral cavity on an average is 37 degrees Celsius without significant changes- provide a stable environment to survive
- Saliva has stable pH of 6.5-7, the favorable pH for most species of bacteria
- it keeps the bacteria hydrated and serves as a medium for the transportation of nutrients to microorganisms
What factors affect oral microbiome composition?
- Diet
- pH
- oxygen
- ligand for bacterial adhesion
- interactions among the bacteria
The human microbiome consists of…
Core microbiome
Variable microbiome
What does the core microbiome consist of?
The core microbiome consists of predominant species that exist at different sites of the body under healthy conditions
What does variable microbiome consist of?
The variable microbiome has evolved in response to lifestyle and genotype of an individual
Explain the development of the oral microbiome
- sterile inoculated with microorganisms from the first feeding onward
- Once tooth eruption begins, more surfaces are established for colonization. Development of gingival crevices occurs for the colonization of periodontal microbes
- Invaded mainly by aerobes by the 1st year and May include streptococcus, lactobacillus, antimyces, neisseria and veillonella
What are the first aerobes to invade the oral microbiome in the 1st year?
-Invaded mainly by aerobes by the 1st year and May include streptococcus, lactobacillus, antimyces, neisseria and veillonella
What are the functions of the oral microbiome?
- protective
- metabolic
- immunogenic
How does the oral microbiome provide protective functions?
- Occupy receptor sites which could be used by harmful bacteria
- Barrier function of skin and mucosa
How does the oral microbiome perform metabolic functions?
- digestion of food and nutrition
- generation of energy
- processing and detoxification of environmental chemicals
How does the oral microbiome perform immunogenicity functions ?
- differentiation and maturation of the host mucosa and its immune system
- maintenance of the immune system and the balance between pro-inflammatory and anti-inflammatory processes
When is dental decay frequently seen?
Dental decay frequently seen in oral cavity
What causes biofilm/plaque formation?
- Caused by plaque forming bacteria
- ferments carbohydrates when fermentable foods are eaten frequently
- the low pH in the plaque is sustained and a net loss of mineral tooth and selects for aciduric organisms
- Store polysaccharide secrete acid long after the food has been swallowed
What is biofilm?
A complex of microorganisms that are embedded in a matrix of extracellular polymeric substances they have produced, and they are attached to either an inert or living surface and formed by one or more species
Why does biofilm formation constitute an effective adaptive strategy?
This is because of behavior offers four major advantages:
- Protection from adverse environmental factors
- Increased availability of nutrients for growth
- Increased binding of water molecules, reducing the possibility of dehydration
- Proximity to progeny and other bacteria, facilitating higher rates of DNA transfer
What type of medical implant is usually infected?
When a medical implant is infected, it is usually biofilm