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Microbiology PMY 3 > Relationships L1 > Flashcards

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

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2
Q

Microbiome vary with…

A

The type of tissue condition

pH, moisture, type of microbes present

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3
Q

Can microbiome cause diseases?

A

Can cause disease if reach in abnormal location or if epithelial defense is impaired

Generally non-pathogenic

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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
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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
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6
Q

What are risks associated with the microbiota?

A

Opportunistic pathogens

  • surface breach allows bacterial entry
  • immunocompromised hosts
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7
Q

What are the general host defenses?

A
  • Physical barriers
    • skin
      • keratin
      -Mucous membranes(e.g. throat, mouth)
  • chemical barriers to infection
    • Acidic pH: stomach, skin, vagina
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8
Q

Give the functions of mucous membranes

A

In throat, mouth

  • trap, destroy pathogens
  • Mucous layers sheds off
  • Cilia, remove microbe from lungs
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9
Q

Give some examples of sterile sites in the body

A

The heart

The brain

Erythrocytes/blood

Kidneys

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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

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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

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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

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13
Q

What is the body’s largest organ?

A

The skin

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14
Q

The skin is colonized by ….

A

Diverse microorganisms

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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:

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16
Q

Explain how the skin was involved in diseases?

A

Propionibacterium acnes

- fatty acid induce inflammation 
- inflamed sebaceous gland
- causes acne
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17
Q

When is the skin sterile?

A

Skin is sterile in utero, but colonization occurs immediately after birth

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18
Q

What is the colonization of skin driven by?

A
  • Endogenous host factors e.g. sex, age

- Exogenous environmental factors e.g. climate

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19
Q

What are the factors contributing to variation in the skin microbbiome?

A
  1. Host physiology - sex, age and site
  2. Environment- climate, geographical location
  3. Host genotype- susceptibility genes such as filaggrin
  4. Lifestyle- occupation, hygiene
  5. Pathobiology- underlying conditions such as diabetes
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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
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21
Q

What is the second largest microbial community in humans?

A

Oral microbiome

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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

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23
Q

What factors contribute to microbial life in the oral microbiome?

A
  1. The normal temperature of the oral cavity on an average is 37 degrees Celsius without significant changes- provide a stable environment to survive
  2. 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
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24
Q

What factors affect oral microbiome composition?

A
  • Diet
  • pH
  • oxygen
  • ligand for bacterial adhesion
  • interactions among the bacteria
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25
Q

The human microbiome consists of…

A

Core microbiome

Variable microbiome

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26
Q

What does the core microbiome consist of?

A

The core microbiome consists of predominant species that exist at different sites of the body under healthy conditions

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27
Q

What does variable microbiome consist of?

A

The variable microbiome has evolved in response to lifestyle and genotype of an individual

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28
Q

Explain the development of the oral microbiome

A
  • 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
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29
Q

What are the first aerobes to invade the oral microbiome in the 1st year?

A

-Invaded mainly by aerobes by the 1st year and May include streptococcus, lactobacillus, antimyces, neisseria and veillonella

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30
Q

What are the functions of the oral microbiome?

A
  • protective
  • metabolic
  • immunogenic
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31
Q

How does the oral microbiome provide protective functions?

A
  • Occupy receptor sites which could be used by harmful bacteria
  • Barrier function of skin and mucosa
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32
Q

How does the oral microbiome perform metabolic functions?

A
  • digestion of food and nutrition
  • generation of energy
  • processing and detoxification of environmental chemicals
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33
Q

How does the oral microbiome perform immunogenicity functions ?

A
  • 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
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34
Q

When is dental decay frequently seen?

A

Dental decay frequently seen in oral cavity

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35
Q

What causes biofilm/plaque formation?

A
  • 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
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36
Q

What is biofilm?

A

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

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37
Q

Why does biofilm formation constitute an effective adaptive strategy?

A

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
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38
Q

What type of medical implant is usually infected?

A

When a medical implant is infected, it is usually biofilm

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39
Q

What type of infection is the most difficult to treat? What does this cause?

A

Biofilm infection is more difficult to treat than other non-biofilm infections resulting from the same microbes not in a biofilm

40
Q

How are many nosocomial infections acquired?

A

A large proportion of nosocomial infections are associated with the implantation of a biomedical device

41
Q

How much biomedical devices are used per annum?

A

Estimated 5 million medical devices or implants are used per annum in the US alone

42
Q

On which devices have biofilm been observed?

A

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
Q

What are the 3 defenses of the upper respiratory tract?

A
  • Cough (voluntary / involuntary)
  • cucocillary apparatus
  • Antimicrobial compounds: lysozyme, lactoferrin, secretory IgA
44
Q

How does cucocilary apparatus defend the upper respiratory tract?

A
  • ciliated cells lining the airways
  • secretory cells
  • Mucous
    • keep the epithelium moist
    • traps particles from inspired air
45
Q

What are the requirements for microbes to successfully colonize the upper respiratory tract?

A
  • Attach to the epithelial lining
  • Grow on mucosal surface
  • Interact with host immune system
  • Replicate
  • Penetrate the mucous barrier(lower)
46
Q

How long does it take for the up respiratory tract acquire flora?

A

Usually sterile at birth, but takes 2-3 days to acquire flora

47
Q

What are the Big four bacteria that colonize the nasopharynx?

A
  1. Streptococcus pneumoniae
  2. staphylococcus aureus
  3. Moraxella catarrhalis
  4. Hemophilus influenza
48
Q

What are the other bacteria that occupy the nasopharynx(aside from the big four)?

A
  • Staphylococcus epidermis
  • Streptococcus pyogenes
  • Propionibacterium
  • Neisseria spp.
  • Mycoplasma
  • Corynebacterium diphtheridae
49
Q

What are the environmental factors that affect nasal flora/ colonies in nasopharynx ?

A
  • temperature
  • humidity
  • pollution
  • cigarette smoke
  • antibiotics
50
Q

Why are there many nose and throat infections?

A

-Natural habitat of common pathogenic bacteria causing infection of the nose, throat and lungs

51
Q

What happens first URT(upper respiratory tract ) infection of viruses or bacteria?

A

URT viral infection has been found to precede URT bacterial outgrowth

52
Q

Why is knowledge of the microbiome of the URT important?

A
  • considered sterile
  • studies from the last decade reveal: it consists of 9 core genera:

Prevotella. Staphylococcus

Sphingomonas. Streptococcus

Psyedomonas

Acinetobacter

Fusobacterium

Megasphaera

Veillonella

53
Q

What are the most significant of the nine genera and why?

A

They are known to cause respiratory disorders

  • Moraxella catarrhalis
  • Haemophilus influenzae
  • Streptococcus pneumoniae
54
Q

What are the defenses of the Lower Respiratory Tract?

A
  • moist mucous covered surfaces: trap particle and organisms
  • cell surface IgA, lysozymes
  • ciliated epithelium
  • cough reflex and epiglottis
  • pulmonary macrophages
55
Q

How do ciliated epithelium defend the lower respiratory tract?

A

Clears trapped particles and organism from airway

56
Q

How do cough reflex and epiglottis defend the LRT?

A

Prevents aspiration of particles and irritants into lower airway

57
Q

How do pulmonary macrophages defend the LRT?

A

Phagocytize foreign particles and organisms in alveolar spaces

58
Q

What 3 biological factors determine the lung microbiome?

A
  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
Q

What is health?

A

The balance of immigration and elimination

60
Q

How does health have an impact on lung microbiome?

A

In health, the 3 factors of the lung microbiome make conditions inhospitable for bacterial growth, resulting in relatively little bacterial reproduction

61
Q

What is the effect of the disease state of on the lung microbiome?

A

In disease state, the regional growth conditions of the lungs change dramatically, creating permissive niches for selective bacterial reproduction

62
Q

Give examples of microbial immigration

A
  • Microaspiration
  • inhalation of bacteria
  • direct mucosal dispersion
63
Q

Give examples of microbial elimination

A
  • cough
  • Mucociliary clearance.
  • Innate and adaptive host defenses
64
Q

Give examples of regional growth conditions

A
  • nutrient availability
  • oxygen tension
  • temperature
  • pH
  • Concentration of inflammatory
  • Activation of inflammatory cells
  • local microbial competition
  • host epithelial cell interactions
65
Q

What is cystic fibrosis?

A

Disease and persistent inflammation in the lungs can change and modify the composition of the microbiome

66
Q

What causes Cystic fibrosis?

A
  • 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
Q

What pathogens are common early in life in patients with cystic fibrosis?

A

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
Q

Recent research suggests….

A

That the lung microbiome plays a significant role in asthma severity and response to treatment

69
Q

What is seen in patients with less severe asthma ?

A

Patients with less severe asthma showed decreased T helper cytokines and increased enterococcus bacteria, but normal pulmonary function tests

70
Q

What is seen in patients with more severe asthma?

A

Patients with more severe asthma was associated with increased pro-inflammatory cytokine, increased strep pneumonia bacteria, and decreased pulmonary function tests

71
Q

What effect does respiratory viral infection have?

A

Viral infection predispose patients to secondary bacterial infections, which often have a more severe clinical course

72
Q

What causes respiratory viral infections?

A

Attributed to:

  • Direct mucosal/ epithelial damage
  • increased bacterial colonization of the ( URT and LRT, respectively)
  • Dysfuction of immune responses
73
Q

Why was the gastric microbiome thought to be sterile?

A

Due to acid production, thought to be sterile but has its core microbiome

74
Q

What are the five major families of the stomach?

A
  1. Firmicutes
  2. Bacteroidites
  3. Actinobacteria
  4. Fusobacteria
  5. Proteobacteria
75
Q

What bacteria DOMINATE the stomach, at a general level?

A

At the genera level, the healthy human stomach is dominated by Prevotella, Streptococcus, Veillonella, Rothia and Haemophilus

76
Q

What molecular factors play a role in colonization?

A

Cytoplasmic urease

Urel

77
Q

How does urel play a role in colonization?

A

Allows passage of urea into the cytoplasm of the bacteria

78
Q

How does Cytoplasmic urease play a role in colonization?

A

Converts urea to carbon dioxide and ammonia

79
Q

What is the largest microbiome in humans?

A

Gut microbiome-includes 1000 different species of known bacteria

Gut microbiome is constantly evolving

80
Q

How similar is everyone’s gut microbiome to everyone else?

A

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
Q

How are newborns colony made unique to them?

A
  • Rapidly colonized with micro-organisms from the mother and the surrounding environment
  • Influenced by breastfeeding vs formula fed babies
82
Q

What are the functions of the gut microbiome?

A
  • metabolic functions
  • Protect against foreign pathogens

-immune system education
(Complex and bidirectional)

83
Q

What are the metabolic functions of the gut microbiome?

A
  • 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
Q

Give examples of Gut microbiome diseases

A
  • Ulcerative colitis
  • Irritable bowel syndrome
  • Type 2 diabetes
85
Q

What is ulcerative colitis?

A

A bowel disease that is characterized by inflammation with ulcer formation in the lining of colon(large intestine)

86
Q

What irritable bowel syndrome?

A

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
Q

What is type 2 diabetes?

A

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
Q

How many bacterial species are in the vaginal microbiome?

A

Over 250 species of bacteria detected using genomic sequencing

89
Q

What is the primary colonizing bacteria of a healthy individual?

A

The genus: lactobacillus ex: L. crispatus

90
Q

What is the benefit of lactic acid pathogenically?

A

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
Q

What happens when women lack a dominant lactobacilllus in their microbiome?

A

This causes a higher risk of acquiring STIs and other conditions including bacterial vaginiosis

92
Q

What are some other benefits aside from prevention of pathogenic reasons?

A
  • competition for adherence
  • hydrogen peroxide production ( a broad-spectrum antimicrobial)
  • Bacteriocinsh(target-specific antimicrobials)
93
Q

What gram negative bacteria are frequently found in the vagina?

A

Gram negative enteric organisms such as E. Coli

94
Q

What gram positive bacteria are frequently found in the gagina?

A

Atophobium vaginae, peptostreptococcus spp., staphylococcus spp., Streptococcus spp., and bacteroides spp., fusobacterium spp., gardnerella vaginalis, mobiluncus, prevotella spp.

95
Q

Mycoplasma and ureaplasma are often found …

A

In the vagina

Microbiology PMY 3 (24 decks)

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