Microbiology Flashcards
supragingival plaque is dominated by what type of organisms?
saccharolytic, facultative, and adhesive organisms; G+/-
*saccharolytic = lowers pH of a glc-based growth medium
subgingival plaque is dominated by what type of organisms?
asaccharolytic, anaerobic, weakly adherent, & motile organisms; dominated by G-
what is the predominant of the supra-gingival bacteria? the types of it?
streptococci
4 main groups: mutans salivarius Anginosus (viridans) mitis
S. salivarius?
most areas of mouth; prefers mucosal surfaces, esp tongue
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)
S. gordonii/sanguis?
- member of viridans
- G(+)
- pioneer bacterium
streptococcus intermedius?
- in biofilms
- produces hyaluronidase (breaks down ECM of CT)
- periodontal disease can result
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
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+
eubacterium?
- pleomorphic rods/filaments in caries & periodontal disease
- 50% of anaerobes of periodontal pockets
propionibacterium?
- G+, strict anaerobic bacilli
- rod-shaped or branched (pleomorphic)
- root surf & plaque
where is actinomyces commonly found?
supragingival plaque
A. naeslundii?
- another early recolonizer of clean teeth
- coaggregates w/ streptococci, fusobact, and veillonella
- provides attachment for certain G- anaerobes
A. odontolyticus?
in deep dentinal caries
Most frequent causative agent of Actinomycosis?
A. israelii
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
bacteroides group?
B. fragilis
Porphyromonas
Prevotella
Tanarella
poryphyromonas & prevotella?
- G(-), black (heme accum.) colonies
- unusual endotoxin (LPS)
tanarella forsythia?
- anaerobic, non pigmented
- periodontal disease
- member of RED complex
- secretes trpysin-like proteases
- in progression of bone loss
porphyromonas gingivalis?
- periodontal disease
- member of RED complex
- proteolytic enzymes: gingipains, collagenases, dipeptidyl aminopeptidase IV
prevotella intermedia?
- periodontal disease
- imp in necrotic ulcerative gingivitis
aggregatibacter actinomycetemcomitans (Aa)?
- in dental plaque, periodontal pockets, gingival sulcus
- preadolescents localized juvenile & advanced aggressive periodontal disease
- produces leukotoxin, chemotaxis inhibiting factor, & collagenase
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?
- pellicle formation
- primary colonization
- secondary colonization
- 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?
- Miller’s Chemico - parasitic theory
- Proteolytic theory
- 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?
- can’t predict specific sites of caries
- initiation of smooth surface caries not explained.
- 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
