Relationships L1 Flashcards
1
Q
What is a human microbiome?
A
A community of microorganisms (such as bacteria, fungi, and vuruses) that inhabit a particular environment
2
Q
Microbiome vary with…
A
The type of tissue condition
pH, moisture, type of microbes present
3
Q
Can microbiome cause diseases?
A
Can cause disease if reach in abnormal location or if epithelial defense is impaired
Generally non-pathogenic
4
Q
Why should a microbiome be studied?
A
- 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
5
Q
Explain the contributions of human microbiota to human health
A
- 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
6
Q
What are risks associated with the microbiota?
A
Opportunistic pathogens
- surface breach allows bacterial entry
- immunocompromised hosts
7
Q
What are the general host defenses?
A
- Physical barriers
- skin
- keratin
- skin
- chemical barriers to infection
- Acidic pH: stomach, skin, vagina
8
Q
Give the functions of mucous membranes
A
In throat, mouth
- trap, destroy pathogens
- Mucous layers sheds off
- Cilia, remove microbe from lungs
9
Q
Give some examples of sterile sites in the body
A
The heart
The brain
Erythrocytes/blood
Kidneys
10
Q
Give factors affecting human microbiome
A
- diet
- medications
- infections
- genetics
-infant feeding(breast vs formula)
Less bacterial diversity selected bacteria which metabolizes carbohydrates
-method of delivery
11
Q
How does method of delivery afffect the hospital?
A
Method of delivery( vaginal vs C-section)
C-section: dominated by Enterococcus and klebsiella, which circulate in hospitals
12
Q
How do human microbes adjust?
A
- 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
13
Q
What is the body’s largest organ?
A
The skin
14
Q
The skin is colonized by ….
A
Diverse microorganisms
15
Q
What is the function of skin?
A
- A physical barrier
- protecting our bodies from potential assault by foreign organisms or toxic substances
- difficult to colonize
- Dry, acidic, protective oils
-Disease involvement:
16
Q
Explain how the skin was involved in diseases?
A
Propionibacterium acnes
- fatty acid induce inflammation - inflamed sebaceous gland - causes acne
17
Q
When is the skin sterile?
A
Skin is sterile in utero, but colonization occurs immediately after birth
18
Q
What is the colonization of skin driven by?
A
- Endogenous host factors e.g. sex, age
- Exogenous environmental factors e.g. climate
19
Q
What are the factors contributing to variation in the skin microbbiome?
A
- 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
20
Q
What are the requirements of Staphylococcus aureus ( S. Aureus) colonization?
A
- 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
21
Q
What is the second largest microbial community in humans?
A
Oral microbiome
22
Q
What body parts comprise the oral microbiome?
A
The teeth, tongue, cheeks, gingival sulcus, tonsils, hard palate and soft palate provide a rich environment in which microorganisms can flourish
23
Q
What factors contribute to microbial life in the oral microbiome?
A
- 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
24
Q
What factors affect oral microbiome composition?
A
- Diet
- pH
- oxygen
- ligand for bacterial adhesion
- interactions among the bacteria
25
The human microbiome consists of...
Core microbiome
Variable microbiome
26
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
27
What does variable microbiome consist of?
The variable microbiome has evolved in response to lifestyle and genotype of an individual
28
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
29
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
30
What are the functions of the oral microbiome?
- protective
- metabolic
- immunogenic
31
How does the oral microbiome provide protective functions?
- Occupy receptor sites which could be used by harmful bacteria
- Barrier function of skin and mucosa
32
How does the oral microbiome perform metabolic functions?
- digestion of food and nutrition
- generation of energy
- processing and detoxification of environmental chemicals
33
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
34
When is dental decay frequently seen?
Dental decay frequently seen in oral cavity
35
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
36
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
37
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
38
What type of medical implant is usually infected?
When a medical implant is infected, it is usually biofilm
39
What type of infection is the most difficult to treat? What does this cause?
Biofilm infection is more difficult to treat than other non-biofilm infections resulting from the same microbes not in a biofilm
40
How are many nosocomial infections acquired?
A large proportion of nosocomial infections are associated with the implantation of a biomedical device
41
How much biomedical devices are used per annum?
Estimated 5 million medical devices or implants are used per annum in the US alone
42
On which devices have biofilm been observed?
Microbial infections have been observed on most, if not all, such devices, including:
-prosthetic heart valves, orthopedic implants, intra vascular catheters, artificial hearts, left ventricular assist devices, cardiac pacemakers, vascular prostheses, urinary catheters
43
What are the 3 defenses of the upper respiratory tract?
- Cough (voluntary / involuntary)
- cucocillary apparatus
- Antimicrobial compounds: lysozyme, lactoferrin, secretory IgA
44
How does cucocilary apparatus defend the upper respiratory tract?
- ciliated cells lining the airways
- secretory cells
- Mucous
- keep the epithelium moist
- traps particles from inspired air
45
What are the requirements for microbes to successfully colonize the upper respiratory tract?
- Attach to the epithelial lining
- Grow on mucosal surface
- Interact with host immune system
- Replicate
- Penetrate the mucous barrier(lower)
46
How long does it take for the up respiratory tract acquire flora?
Usually sterile at birth, but takes 2-3 days to acquire flora
47
What are the Big four bacteria that colonize the nasopharynx?
1. Streptococcus pneumoniae
2. staphylococcus aureus
3. Moraxella catarrhalis
4. Hemophilus influenza
48
What are the other bacteria that occupy the nasopharynx(aside from the big four)?
- Staphylococcus epidermis
- Streptococcus pyogenes
- Propionibacterium
- Neisseria spp.
- Mycoplasma
- Corynebacterium diphtheridae
49
What are the environmental factors that affect nasal flora/ colonies in nasopharynx ?
- temperature
- humidity
- pollution
- cigarette smoke
- antibiotics
50
Why are there many nose and throat infections?
-Natural habitat of common pathogenic bacteria causing infection of the nose, throat and lungs
51
What happens first URT(upper respiratory tract ) infection of viruses or bacteria?
URT viral infection has been found to precede URT bacterial outgrowth
52
Why is knowledge of the microbiome of the URT important?
- considered sterile
- studies from the last decade reveal: it consists of 9 core genera:
Prevotella. Staphylococcus
Sphingomonas. Streptococcus
Psyedomonas
Acinetobacter
Fusobacterium
Megasphaera
Veillonella
53
What are the most significant of the nine genera and why?
They are known to cause respiratory disorders
- Moraxella catarrhalis
- Haemophilus influenzae
- Streptococcus pneumoniae
54
What are the defenses of the Lower Respiratory Tract?
- moist mucous covered surfaces: trap particle and organisms
- cell surface IgA, lysozymes
- ciliated epithelium
- cough reflex and epiglottis
- pulmonary macrophages
55
How do ciliated epithelium defend the lower respiratory tract?
Clears trapped particles and organism from airway
56
How do cough reflex and epiglottis defend the LRT?
Prevents aspiration of particles and irritants into lower airway
57
How do pulmonary macrophages defend the LRT?
Phagocytize foreign particles and organisms in alveolar spaces
58
What 3 biological factors determine the lung microbiome?
1. Microbial immigration into the airways
2. Elimination of microbes from thee airways
3. The relative reproduction rates of its community members, as determined by regional growth conditions
59
What is health?
The balance of immigration and elimination
60
How does health have an impact on lung microbiome?
In health, the 3 factors of the lung microbiome make conditions inhospitable for bacterial growth, resulting in relatively little bacterial reproduction
61
What is the effect of the disease state of on the lung microbiome?
In disease state, the regional growth conditions of the lungs change dramatically, creating permissive niches for selective bacterial reproduction
62
Give examples of microbial immigration
- Microaspiration
- inhalation of bacteria
- direct mucosal dispersion
63
Give examples of microbial elimination
- cough
- Mucociliary clearance.
- Innate and adaptive host defenses
64
Give examples of regional growth conditions
- nutrient availability
- oxygen tension
- temperature
- pH
- Concentration of inflammatory
- Activation of inflammatory cells
- local microbial competition
- host epithelial cell interactions
65
What is cystic fibrosis?
Disease and persistent inflammation in the lungs can change and modify the composition of the microbiome
66
What causes Cystic fibrosis?
- Manifested by a decrease in the diversity of the original microbiome
- In patients with CF, different bacteria inhabit different parts of the lung at various stages of the infection
67
What pathogens are common early in life in patients with cystic fibrosis?
Methicillin-sensitive Staphylococcus aureus (MSSA) and Hemophilus influenzae are common pathogens early in life of such patients
As the disease progresses, more virulent pathogens— such and Pseudomonas aeruginosa and methicillin-resistant S. aureus (MRSA) - invade the lung and cause pulmonary damage
68
Recent research suggests....
That the lung microbiome plays a significant role in asthma severity and response to treatment
69
What is seen in patients with less severe asthma ?
Patients with less severe asthma showed decreased T helper cytokines and increased enterococcus bacteria, but normal pulmonary function tests
70
What is seen in patients with more severe asthma?
Patients with more severe asthma was associated with increased pro-inflammatory cytokine, increased strep pneumonia bacteria, and decreased pulmonary function tests
71
What effect does respiratory viral infection have?
Viral infection predispose patients to secondary bacterial infections, which often have a more severe clinical course
72
What causes respiratory viral infections?
Attributed to:
- Direct mucosal/ epithelial damage
- increased bacterial colonization of the ( URT and LRT, respectively)
- Dysfuction of immune responses
73
Why was the gastric microbiome thought to be sterile?
Due to acid production, thought to be sterile but has its core microbiome
74
What are the five major families of the stomach?
1. Firmicutes
2. Bacteroidites
3. Actinobacteria
4. Fusobacteria
5. Proteobacteria
75
What bacteria DOMINATE the stomach, at a general level?
At the genera level, the healthy human stomach is dominated by Prevotella, Streptococcus, Veillonella, Rothia and Haemophilus
76
What molecular factors play a role in colonization?
Cytoplasmic urease
Urel
77
How does urel play a role in colonization?
Allows passage of urea into the cytoplasm of the bacteria
78
How does Cytoplasmic urease play a role in colonization?
Converts urea to carbon dioxide and ammonia
79
What is the largest microbiome in humans?
Gut microbiome-includes 1000 different species of known bacteria
Gut microbiome is constantly evolving
80
How similar is everyone’s gut microbiome to everyone else?
One third of our gut microbiota is common to most people, while two thirds are specific to each one of us
Synonymous to identity card
81
How are newborns colony made unique to them?
- Rapidly colonized with micro-organisms from the mother and the surrounding environment
- Influenced by breastfeeding vs formula fed babies
82
What are the functions of the gut microbiome?
- metabolic functions
- Protect against foreign pathogens
-immune system education
(Complex and bidirectional)
83
What are the metabolic functions of the gut microbiome?
- aid in host digestion and nutrition
- generate nutrients from substrates that are otherwise indigestible by the host
- liberate short chain fatty acids (SCFA) from indigestible dietary fibers. SCFA are an important energy source for intestinal mucousa and critical for control immune responses
84
Give examples of Gut microbiome diseases
- Ulcerative colitis
- Irritable bowel syndrome
- Type 2 diabetes
85
What is ulcerative colitis?
A bowel disease that is characterized by inflammation with ulcer formation in the lining of colon(large intestine)
86
What irritable bowel syndrome?
A disorder of the intestines commonly marked by abdominal pain, bloating, and changes in a person’s bowel habits. This may include diarrhea or constitution, or both, with one occurring after the other
87
What is type 2 diabetes?
A condition in which cells cannot use blood sugar(glucose) efficiently for energy. This happens when the cells become insensitive to insulin and the blood sugar gradually gets too high
88
How many bacterial species are in the vaginal microbiome?
Over 250 species of bacteria detected using genomic sequencing
89
What is the primary colonizing bacteria of a healthy individual?
The genus: lactobacillus ex: L. crispatus
90
What is the benefit of lactic acid pathogenically?
Protection against infections
Lactobacilli Inhibits growth of pathogenic microorganisms, e.g. Bacteroides fragility, E. coli, Gardnerella vaginalis, mobiluncus spp., Neisseria gonorrhea, Peptostreptococcus anaerobius, P. Bivia and staphylococcus aureus
91
What happens when women lack a dominant lactobacilllus in their microbiome?
This causes a higher risk of acquiring STIs and other conditions including bacterial vaginiosis
92
What are some other benefits aside from prevention of pathogenic reasons?
- competition for adherence
- hydrogen peroxide production ( a broad-spectrum antimicrobial)
- Bacteriocinsh(target-specific antimicrobials)
93
What gram negative bacteria are frequently found in the vagina?
Gram negative enteric organisms such as E. Coli
94
What gram positive bacteria are frequently found in the gagina?
Atophobium vaginae, peptostreptococcus spp., staphylococcus spp., Streptococcus spp., and bacteroides spp., fusobacterium spp., gardnerella vaginalis, mobiluncus, prevotella spp.
95
Mycoplasma and ureaplasma are often found ...
In the vagina
