- in mucosal surfaces & plaque - opportunistic pathogen (in abscesses) - earliest colonizers of cleanse tooth surf - cause of sub-acute bacterial endocarditis (prophylatic AB required for some pts undergoing oral procedures)

- member of viridans - G(+) - pioneer bacterium

G+, anaerobic streptococci, which can cause carious dentine, in pulp chambers, root canals, and advanced periodontal disease ONLY genus among anaerobic G+ cocci encountered in clinical infections infections - can be in all body sites

- pleomorphic rods/filaments in caries & periodontal disease - 50% of anaerobes of periodontal pockets

- G+, strict anaerobic bacilli - rod-shaped or branched (pleomorphic) - root surf & plaque

- another early recolonizer of clean teeth - coaggregates w/ streptococci, fusobact, and veillonella - provides attachment for certain G- anaerobes

- anaerobic, non pigmented - periodontal disease - member of RED complex - secretes trpysin-like proteases - in progression of bone loss

Microbiology Flashcards by Laura Vo

supragingival plaque is dominated by what type of organisms?

saccharolytic, facultative, and adhesive organisms; G+/-

*saccharolytic = lowers pH of a glc-based growth medium

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subgingival plaque is dominated by what type of organisms?

asaccharolytic, anaerobic, weakly adherent, & motile organisms; dominated by G-

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what is the predominant of the supra-gingival bacteria? the types of it?

streptococci

4 main groups:
mutans
salivarius
Anginosus (viridans)
mitis

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S. salivarius?

most areas of mouth; prefers mucosal surfaces, esp tongue

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S. viridans?

in mucosal surfaces & plaque
opportunistic pathogen (in abscesses)
earliest colonizers of cleanse tooth surf
cause of sub-acute bacterial endocarditis (prophylatic AB required for some pts undergoing oral procedures)

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S. gordonii/sanguis?

member of viridans
G(+)
pioneer bacterium

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streptococcus intermedius?

in biofilms
produces hyaluronidase (breaks down ECM of CT)
periodontal disease can result

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peptostreptococcus?

G+, anaerobic streptococci, which can cause carious dentine, in pulp chambers, root canals, and advanced periodontal disease

ONLY genus among anaerobic G+ cocci encountered in clinical infections
infections - can be in all body sites

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lactobacillus types and etc?

L. casei, L. fermentum, L. acidophilus
inc in advanced caries of enamel & root surf (pit & fissure, dentinal caries)
most aciduric oral species
G+

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eubacterium?

pleomorphic rods/filaments in caries & periodontal disease

- 50% of anaerobes of periodontal pockets

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propionibacterium?

G+, strict anaerobic bacilli
rod-shaped or branched (pleomorphic)
root surf & plaque

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where is actinomyces commonly found?

supragingival plaque

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A. naeslundii?

another early recolonizer of clean teeth
coaggregates w/ streptococci, fusobact, and veillonella
provides attachment for certain G- anaerobes

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A. odontolyticus?

in deep dentinal caries

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Most frequent causative agent of Actinomycosis?

A. israelii

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fusobacterium nucleatum?

associated w/ gum disease
key comp of periodontal plaque & gingivitis
can adhere to wide range of G+/- plaque MOs
crucial! if can block this, then can prevent most other periodontal pathogens

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bacteroides group?

B. fragilis
Porphyromonas
Prevotella
Tanarella

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poryphyromonas & prevotella?

G(-), black (heme accum.) colonies

- unusual endotoxin (LPS)

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tanarella forsythia?

anaerobic, non pigmented
periodontal disease
member of RED complex
secretes trpysin-like proteases
in progression of bone loss

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porphyromonas gingivalis?

periodontal disease
member of RED complex
proteolytic enzymes: gingipains, collagenases, dipeptidyl aminopeptidase IV

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prevotella intermedia?

periodontal disease

- imp in necrotic ulcerative gingivitis

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aggregatibacter actinomycetemcomitans (Aa)?

in dental plaque, periodontal pockets, gingival sulcus
preadolescents localized juvenile & advanced aggressive periodontal disease
produces leukotoxin, chemotaxis inhibiting factor, & collagenase

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Eikenella corrodens?

infrequent human pathogen capable of causing extraoral infections

capnocytophaga?

G(-) facultative anaerobes

- occasional pathogen found in oral diseases & brain abscesses

spirochetes?

- present in advanced periodontitis - genus Treponema - absent from mouth until teeth erupt - greatly inc gingivitis

treponema denticola?

- member of RED complex - spirochete; periodontal disease - adheres to fibroblasts & epithelial cells, ECM - produces methyl mercaptan---contribute to halitosis

sequence of events information of plaque?

1. pellicle formation 2. primary colonization 3. secondary colonization 4. tertiary colonization

diff betw early and late colonizers?

- early = utilize O2 and produce CO2 | - late = produce H2 & reducing agents

oxidation-reduction potential rises w/ plaque age. t/f?

FALSE, it falls w/ plaque age *decreasing Eh correlates w/ increasing anaerobes

3 theories proposed for etiology of caries?

1. Miller's Chemico - parasitic theory 2. Proteolytic theory 3. Proteolysis - chelation theory

what are the 3 factors involved in Miller's chemico-parasitic theory?

carb substrate, acid, oral micro organisms

objections to miller's?

1. can't predict specific sites of caries 2. initiation of smooth surface caries not explained. 3. unable to explain caries-free and caries-prone pop.

polysaccharides are less easily fermented than monosaccharides by the plaque organisms. T/F?

true

S. mutans & Lactobacilli species attack the ____ fissures, while A. naeslundi and A. viscosus prefer ____ surfaces.

pit; root

______ and ________ also show preference to deep dentinal lesions.

Lactobacilli, A. naeslundi

composition of dental plaque?

80% water; 20% solids

proteolytic theory?

caries = essentially a proteolytic process; breakdown of proteins

proteolysis-chelation theory?

caries = result of simultaneous degradation of organic substances (proteolysis) and dissolution of tooth minerals by a process called chelation.

chelation?

process of complexing of a metallic ion to a complex substance

surfaces of teeth in order of likelihood of caries?

occlusal, buccal, mesial, lingual, distal

most susceptible teeth in order?

MD 1st, MX 1st, MD & MX 2nd molars

chlorhexidine?

an effective oral agent; broad spectrum vs yeasts, fungi, G+/- bact

ribosomes for bacteria?

70s ribosomes (16S and 23S subunits)

L-Phase/Forms bacteria?

bacteria w/ cell walls that lack peptidoglycan.

Techoic acids are exclusive to what type of bacteria?

Gram +

Lysozyme is a glycosidase that hydrolyses ..?

MurNac - GlcNac bond and disrupts peptidoglycan structure.

What activates the alternate complement pathway?

techoic acid

Certain pili (______) has a retraction mechanism.

Type IV

Certain pili (sex pili) are involved in ______.

bacterial conjugation

H antigen?

flagella

K antigen?

Capsule

what recognizes PAMPs?

TLRs

CCW rotation of flagella results in what type of movement? CW rotation?

CCW - fwd movt, run | CW - reorientation, tumble

what type of penicllin would you give to a pt w/ stomach probs?

penicillin V

following respiration, what is the major end product of glc catabolism

co2 & h2o

what layer is the endotoxin found in?

endotoxin in the outer leaf of the lipid bilayer