Exam 1; Periodontal Microbiology Flashcards

1
Q

What is the great plate anomaly

A

everything you see doesn’t necessarily grow on a plate

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2
Q

How many distinct oral species are there

A

700+ >60% have never been cultured

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3
Q

This is an organized cooperating community of organisms with specific inter-bacterial and host-bacterial interactions

A

biofilm

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4
Q

True or False Just as much (~24%) of bacteria is found in your body as found in your mouth

A

True

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5
Q

This occurs when children are not exposed to a variety of bacteria, they develop autoantibodies to commensal bacteria

A

Atopy atopic dermatitis

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6
Q

What occurs in the attachment phase of biofilm formation

A

planktonic bacteria adhere to acquired pellicle

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7
Q

This type of “attacher” contains specific attachment structures (fimbrae, extracellular polymers, glycocalyx)

A

rapid attachers

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8
Q

This type of “attacher” contains no specific mechanism of attachment

A

slow attachers

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9
Q

How can bacterial characteristics change following attachment

A

synthesis of new outer membrane proteins active cellular growth

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10
Q

This type of growth with biofilm formation is cell-to-cell recognition of genetically distinct cell types

A

co-aggregation

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11
Q

What is co-aggreation mediated by

A

protein or glycoprotein receptors on one cell and carbohydrates on the other

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12
Q

What physical characteristics are there involving co-aggregation

A

all cells are suspended “clumps” form, which then attach to the pellicle

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13
Q

This type of growth with biofilm formation involves interactions between suspended and already adhering micro-organisms

A

co-adhesion

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14
Q

What two things is co-adhesion influenced by

A

temperature (no co-adhesion >37°) lactose (high lactose, no co-adhesion)

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15
Q

What three thins occur upon the maturation of the biofilm

A

increase in diversity replication and matrix formation ecological succession

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16
Q

What are the primary colonizers

A

gram+ and gram- streptococci bind pellicle proteins from saliva (high #s) most are beneficial bacteria

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17
Q

What are the secondary colonizers

A

gram- bridge species which bind other bacteria

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18
Q

What is one of the main secondary colonizers

A

F. nucleatum (prolific coagregator)

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19
Q

What are the tertiary colonizers

A

gram- pathogens like prophyromonas gingivalis

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20
Q

What four things occur upon increasing the thickness of a biofilm

A

difficulty in diffusion in and out of the biofilm

an oxygen gradient develops

completely anaerobic conditions ermege in the deeper layers

reverse gradients of fermentation products develop as a result of bacterial metabolism

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21
Q

What is the nutrient source in supragingival plaque

A

dietary products in saliva

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22
Q

What is the nutrient source in subginival plaque

A

periodontal tissues and bone

bacterial hydrolytic enzymes breakdown host macromolecules into peptides and amino acids

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23
Q

What two things compose a biofilm

A

microcolonies (15-20%)

interbacterial matrix

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24
Q

What are the three sources of the matrix

A

dead bacterial cells

saliva

gingival exudate

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25
Q

This is the backone of the biofilm

A

exopolysaccharides

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26
Q

What four characteristics compose the lower layer of the biofilm

A

dense layer of microbes

polysaccharide matrix

tighly bound together

steep diffusion gradients (stuff cannot penetrate)

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27
Q

What are two characteristics of the loose layer

A

irregular in appearance

extends into surrounding medium

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28
Q

What are three characteristics of the fluid layer

A

stationary sublayer

fluid layer in motion

nourishes the biofilm by molecular diffusion

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29
Q

The shape of micro-colonies depends on what

A

shear force

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30
Q

What shape of microcolonies as a low shear force

A

tower or mushrooms (interdental surface)

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31
Q

What shape of microcolonies has a high shear force

A

elongated colonies capable of oscillation (like kelp)

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32
Q

What three things compose the interbacterial matrix

A

gram positive matrix - very fibrilar

gram negative matrix - very regular

interbacterial carbohydrates

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33
Q

What gives the gram positive matrix its “fibrillarity”

A

dextrans and levans

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34
Q

What are three characteristics of the gram negative matrix

A

tri-laminar vesicles

filled with endotoxins and proteolytic enzymes

probably involved in adherence

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35
Q

What is the energy source of interbacterial carbohydrates

A

dextrans and fructose

36
Q

What forms the primary attachemnt for subgingival plaque

A

cuticle

37
Q

What are two differences between supra and sub gingival plaque

A

no inter-bacterial matrix

more spirochetes and flagellated bacteria

38
Q

Bacterial collaboration is necessary for what

A

succession (of biofilm growth)

39
Q

This species of bacteria is facultative, but uses all the O2 when available

A

Strep. cristatus

40
Q

This bacterial species is a robust anaerobe and binding to strep imporoves survival when O2 is present

A

fusobacterium nucleatum

41
Q

This bacterial species is microaerophilic, obligate anaerobe of which coaggregation is essental to survival when O2 is present

A

prophyromonas gingivalis

42
Q

What were the results of the tissue culture experiment of which involved F. nucleatum and S. cristatus

A

F. N. invaded epithelial cells

S.C. does not invade epithelial cells

after coaggregation, S.C. is carried inside cells via F.N

43
Q

What are the two characteristics of the defense benefit of a biofilm

A

presence of concentrated bacterial enzymes

interbacterial matrix

44
Q

What are the four characteristics of a biofilm regarding protection from external changes

A

diffusion minimal in interior regions

antibiotic and antimicrobial resistance

protection from friction and shearing forces

attachment

45
Q

What are the five characeristsis of a biofilm ragarding transfer of information and genetic material

A

signaling (quorum sensing)

conjugation

transformation

plasmid transfer

transposon transfer

46
Q

This is the regulation of expression of specific genes through accumulation of signaling compounds that mediate intercellular communication

A

quorum sensing

47
Q

Auto-inducer (AI) 1 or 2 turns on when

A

in response to cell density

48
Q

Which bacterial produce AI in high and low levels

A

commensal bacteria = AI in low levls

pathogenic bacteria = AI in high levels

49
Q

AI-2 may determine what

A

the switch from commensal to pathogenic community

50
Q

biofilm bacteria are how many more times antiobiotic resistant than planktonic

A

1000-1500

51
Q

What three things are characteristic of a biofilm growing more slowly

A

antiobiotics depend upon cell turnover for efficacy (targets replication mechanims)

slow-growers express non-specific defnese mechanisms

slow-growers make more exo-polymers

52
Q

These retard diffusion

A

exo-polymers

53
Q

Ion-exchange mechanism prevents what

A

highly charges molecules from reaching deeper zones

54
Q

extracellular enzymes (beta-lactamases, formaldehyde, dehydrogenase, formaldehyde lyase) inactivae what

A

antibiotics

55
Q

Biofilm bacteria express different genes, how?

A

gene transfer

phenotypic expression of biofilm exsistance

56
Q

Why dont oral pathogens not fit the classic concept of a pathogen

A

normally present throughout life

damage requires presence in large numbers

57
Q

What three things are characteristic of the ecological concept of oral pathogens

A

ecological shifts lead to change in proportions

balance shifts in favor of pathogens/disease

periodontal disease is an example of “ecological catastrophe”

58
Q

What three clinical things influence of the structure of the biofilm

A

changed tooth-brushing paradigms

hard to reach interproximal and fissures

non-contact brushing can remove towers and mushrooms by force (power toothbrushes)

59
Q

What are two targets for biofilm therapy

A

AI-2

vaccines that target common resistance genes

60
Q

This can translocate pathogens from pockets to healthy sites

A

periodontal probe

61
Q

These can translocate to neighboring teeth

A

drug-resistant strains

62
Q

Teeth act as reservoirs for the colonization of what

A

implants

63
Q

What are the four steps for a “one-stage, full-mouth disinfection”

A

full mouth scaling and root planing within 25 hours

subgingival irrigation with 1% chlorohexedine

tonge brushing

oral antimicrobial rinse

64
Q

What are two characteristsi of peri-implant plaque

A

plaque can from on implant abutments

implants that fail have a microbial composition similar to periodontal disease

65
Q

What is the non-specific plaque hypothetsis

A

plaque control is important for periodontal treatment

all plaque is considered bad

any accumulation of micro-organiss at or below the gingival margin causes inflammation

66
Q

What is the specific plaque hypothesis

A

specific organisms in dental plaque are the etiological agents

microbial composition of disease sites different from healthy sites

local debridement and systemic antibiotics could control LAP (localized aggressive periodontitis)

67
Q

What are the three prerequisites for disease initiation and progression

A

virulent periodontal pathogen

the local environment

host susceptibility

68
Q

What three properties must the virulent periodontal pathogen have

A

strains (not the species) are imporntant

must express virulence factors

must be in the right location in the site (adjacent to epithelium, in the pocket, etc.)

69
Q

What two properties of colonization by beneficial species influence the local environment

A

dilute levels of pathogens

inhibit pathogens

70
Q

What two properties involving the effect of local “regulon” (subgingival enviroment) influence the local enviroment

A

iron can increase out membrane protein expression in P. gingivalis

S. cristatus can inhibit fimA expression

71
Q

What three things can influence host susceptibility

A

HIV

diabetes

smoking

72
Q

What are the two types of adhesins on bacterial that bind it to host receptors

A

Type I or IV collagen, sialic acid, galactosyl residues

fimbrae outer membrane proteins

73
Q

Veillonella uses this made by streptococci as nutrient utlization of pathogenic mechanisms

A

lactate

74
Q

Campylobacter uses this made by Selenomonas as nutrient utlization of pathogenic mechanisms

A

fomate

75
Q

Porphyromonas uses this from blood in the sulcus as nutrient utlization of pathogenic mechanisms

A

hemin

76
Q

What are the two competitive inhibition pathogenic mechanisms

A

bacteriocins

hydrogen peroxide production (S. sanguis inhibits AA)

77
Q

What are the four colonization pathogenic mechanisms

A

adhesions on bacteria bind to host receptors

coaggregation

nutrient utilization

competitive inhibition

78
Q

What are the three pathogenic mechanisms for overcoming host defenses

A

desquamation of epithelium

antibody prevent binding

phagocytic cells

79
Q

What are two mechanisms behind desquamation of epithelium

A

invade epithelium

bind to underlying cells

80
Q

What are two mechansisms involving antibody prevent binding

A

IgG and IgA proteases (break down of IgG and IgA)

mimic host antigens

81
Q

What are two mechanisms behind phagocytic cell pathogen mechanisms

A

leukotoxin

non-lethal suppression of immune cells

82
Q

What are three characteristics of periodontal pathogens

A

complex microbial profile

sveral uncultivated species

microbial complexes

83
Q

The world workshop in 1996 designated what three pathogens

A

P. gingivalis

A. actinomycetemocomitans

T. forsythia

84
Q

Which three bacteria is there strong evidence they are pathogenic

A

Actinobacillus actinomycetemcomitans (A.A.)

Porphyromonas gingivalis (P. gingivalis)

Bacteriodes forsythus (B. forsythus)

85
Q

Which 7 bacteria is there moderate evidence of pathogenicity

A

C. rectus

E. nodatum

F. nucleatum

P. intermedia/nigrescens

P. micros

S. intermedius-complex

T. denticola

86
Q

Which four bacteria is there initial evidence of pathogenicity

A

E. corrodens

enteric rods

pseudomonas

selenomonas

87
Q

Which bacteria is;

non-motile
gram -
sacchrolytic
capnophilic
round-ended rod
characteristic star-shaped colonies

A

Actinobacillus actinomycetemocomitans

AA