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Pedo Final > Lecture 1 - Oral Ecology and microbial diversity > Flashcards

Lecture 1 - Oral Ecology and microbial diversity Flashcards

1
Q

how do we detect bacterial species?

A

traditional methods include MICROSCOPY, CULTIVATION while new methods include 16S sequencing

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2
Q

do we have more bacterial cells or human cells?

A

bacterial cells

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3
Q

Bray-Curtis beta diversity chart

A

defines that each body site harbors a distinct microbial community

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4
Q

ecology

A

study of interrelationships of organisms and their environment

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5
Q

niche

A

specific combination necessary for survival of an organism

parameters may be PHYSICAL, CHEMICAL and biological

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6
Q

the hard surfaces of teeth are unique because?

A

they are non-shedding. Microorganisms can form stable, thick biofilms (“dental plaque”)

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7
Q

can microorganisms invade soft tissues?

A

yes. in periapical and odontogenic infections

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8
Q

what are some soft oral surfaces bacteria can adhere to?

A

sulcus
tongue
mucosa
gingiva

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9
Q

hard oral surfaces are either ___________ or _________

A

subgingival or supragingival

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10
Q

planktonic

A

floating in water

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11
Q

sessile

A

attached to a surface in biofilms

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12
Q

example of biofilms

A

plaque on teeth
gunk in drains
rings in toilets
slippery coating on rocks in streams

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13
Q

biofilms are made up of ______________ and ____________ in an ________ environment

A

adherent microorganisms
extracellular matrix
aqueous

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14
Q

the sticky material that holds biofilm together is

A

extracellular matrix

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15
Q

what are the 3 stages of biofilm life cycle?

A

attachment
growth
detachment

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16
Q

T/F biofilm can be formed by single bacterial species
T/F biofilms often include many species of bacteria
T/F biofilms also include other micro-organisms like fungi, algae, protozoa

A

T
T
T

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17
Q

What turns on biofilm-adaptive genes?

A

when bacteria detects surfaces
when bacteria detects each other (quorum sensing)
when signals pass between bacteria

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18
Q

____________: stable, slow-growing communities that are highly resistant to antibiotics, host defenses and mechanical disruptions (antiseptics and disinfectants)

A

biofilms

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19
Q

what are the 3 primary mechanism for biofilm antimicrobial resistance?

A
  1. slowing of diffusion
  2. “persister cells”: alive but metabolically inactive survive and repopulate biofilm
  3. exchange of resistance genes
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20
Q

T/F most bacteria in the mouth is free-floating

A

F

They need to attach or they’d be lost

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21
Q

biofilms can cause what 4 things?

A

caries
periodontitis
osteromyelitis
osteonecrosis secondary to bisphosphonate therapy

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22
Q

T/F to prevent oral biofilms we might need to prevent invasive diseases like cellulitis as well

A

T

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23
Q

what are the 3 surface sites for adherence?

A 
host surfaces (receptor molecules)
direct bacterial interactions
extracellular matrix
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24
Q

promotes by providing binding sites or inhibits by agglutinating and clearing

A

salivary binding

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25
Q

salivary binding is done by what 4 methods?

A

antibodies
salivary agglutinins
proline-rich glycoproteins
alpha amylase

26
Q

what common measures are used to disrupt bacterial adherence in the mouth?

A

toothbrush and floss

27
Q

T/F the percentage of oxygen is greater in a closed mouth than in the air

A

F 12-14% oxygen in mouth. 21% in air

28
Q

Positive oxidation-reduction potential means LOW oxygen (T/F)

A

F
+ = aerobe = high oxygen
- = anaerobe = low oxygen

29
Q

what requires oxygen at atmospheric levels for growth?

A

obligate aerobes

30
Q

can switch between aerobic and anaerobic metabolism

A

facultative anaerobes or facultative aerobes

31
Q

requiring low levels of oxygen

A

microaerophilic

32
Q

anaerobic metabolism but tolerates the presence of oxygen

A

aerotolerant anaerobes

33
Q

do not use oxygen as nutrient. Oxygen is toxic, killing or inhibiting growth

A

obligate anaerobes or aerophobes

34
Q

sensitivity of anaerobes to oxygen is due to the genetic inability to make enzymes like:__________, ____ and _________

A

superoxide dismutase
catalase
peroxidase

35
Q

T/F In the absence of enzymes like catalase and peroxidase, oxygen products with superoxide and peroxide cannot cause damage to cellular components

A

F

they can cause damage

36
Q 
Which enzyme(s) detoxify oxygen radicals that are generated by living systems in presence of oxygen?
The distribution of Which enzymes(s) determines their ability to exist in the presence of oxygen?
A

superoxide dismutase
catalase
peroxidase

37
Q

T/F Older plaque gets thick and becomes sheltered from oxygen
Older plaque has higher oxidation-reduction potential and corresponding shift in microflora

A

T

F - lower Eh

38
Q

T/F aerobic species are found primarily in oxygen-protected sites like the sulcus or mature coronal plaque

A

F - anaerobic

39
Q

which species are found in supragingival plaque?

A

facultative and microaerophilic

40
Q

what common therapy is designed to exploit oxygen sensitivity of oral bacteria?

A

3% peroxide

41
Q

T/F bacterial fermentation of sugars to lactate is an example of directly affecting pH

A

F - indirect

Direct method example - drinking soft drink

42
Q

pH normally ranges from __-____

A

5-7.5

43
Q

low pH inhibits most species except:

A

acid tolerant (aciduric) strep and lactobacilli

44
Q

what are the two major physical nutrient niches in oral cavity?

A

supragingival - saliva and ingested food

subgingival - crevicular food and cells

45
Q 
saliva contains:
1
2
3
4
5
A 
1 glycoproteins
2 inorganic salts
3 amino acids
4 glucose
5 vitamins
46
Q

T/F endogenous nutrients are not sufficient for plaque.

endogenous nutrients are not sufficient for caries.

A

F (they are sufficient)

T - they need exogenous carbs

47
Q

which secretory immunoglobulin in saliva prevents adhesion?

A

IgA

48
Q

which immunoglobulin in crevicular fluid is directed against periodontally important organisms both systemically and locally produced?

A

IgG

49
Q

what is the main defense of innate immunity?

A

epithelial barrier and desqaumation

50
Q

what are the major salivary proteins?

A

alpha-amylase: digests starches and binds bacteria

mucins: lubricants

51
Q

which salivary defense generates superoxide radicals which inactivate bacterial enzymes leading to bacterial death?

A

sialoperoxidase system

52
Q

which salivary defense binds iron so that it is not bioavailable to bacteria?

A

salivary lactoferrin and serum transferrin

53
Q

which salivary defense digest peptidoglycan in bacterial cell wall leading to osmotic disruption and cell death?

A

salivary lysozyme

54
Q

which salivary defense modulates salivary calcium and phosphate chemistry?

A

acidic proline rich proteins and statherin

55
Q

which bacterium converts lactate to propionate?

A

veillonella

56
Q

T/F veillonella lowers pH for acid-sensitive strep

A

F - raises pH

57
Q

Which vitamin is synthesized by veillonella parvula?

A

vitamin K3

58
Q

vitamin K3 is used by which two bacteria?

A

p. gingivalis

P. intermedia

59
Q

Vitamin K3 synthesis and use is an example of what?

A

chain interdependency

60
Q

Which strep bacterium produces enocin to inhibit s. pyogenes?

A

s. salivarius

61
Q

organisms occupy niche, preventing establishment of new strains is:

A

colonization resistance

62
Q

name 6 ecologic determinants

A 
1 surface receptors for adherence
2 oxygen tension (Eh)
3 pH
4 nutrients
5 host inhibitory factors
6 bacterial community interactions

Pedo Final (11 decks)

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