Wk2 Upper GI micro Flashcards
Disease mechanism in dental caries:
microbial proliferation and invasion
Disease mechanism for gingivitis and peridontitis:
host immune response
Factor facilitating dental disease:
plaque biofilm
General definition for plaque biofilm:
Two or more species of bacteria enclosed in a glycocalyx
“Good guys” of oral cavity bacteria:
S. sanguinis
S. mitis
One way good Strep species protect the oral cavity:
hydrogen peroxide production
Typical gram stain for cavity causing bacteria:
gram +
Typical gram stain for bacteria causing disease below the gum line:
gram -
Bad oral Strep?
S. mutans
S. mutans
Shape?
Cocci (beads on a string)
S. mutans
Catalase ?
catalase negative
How do S. mutans feel about oxygen?
facultative anaerobe
S. mutans
? hemolytic
alpha
viridans group
S. mutans
Optochin ?
resistant
S. mutans VF for binding to pellicle?
AgI/II
What is a dental pellicle?
a protein film that forms on the surface enamel by selective binding of glycoproteins from saliva that prevents continuous deposition of salivary calcium phosphate. It forms in seconds after a tooth is cleaned or after chewing. It protects the tooth from the acids produced by oral microorganisms after consuming carbohydrates.
Constituents of the pellicle
synthesize glucans from sucrose
binding site for S. mutans
Gtfs’s
glucosyltransferases
low abundance microbe capable of orchestrating periodontal inflammation by remodeling normal symbiotic microbiota into dysbiotic state:
keystone pathogens
red group
keystone pathogen
spirochete
Treponema denticola
keystone pathogen
gram -
rod
anaerobe
Tannerella forsythia
keystone pathogen
best studied due to culturability
Porphyromonas gingivalis
Gram - rod
SEVERE periodontal disease
Aggregatibacter actinomycetemcomitans
Actinobacillus
Black pigmented colonies on blood auger
P. gingivalis
P. gingivalis
bacitracin ?
resistant
Link between diabetes and periodontal disease:
inflammatory cytokines
Skin infection on floor of mouth
can block airway
Ludwig’s angina
Creamy white lesions
usually tongue or inner cheeks
Candidiasis
Dx for Candidiasis
hyphae on microscopy
Topical Tx’s of candidiasis:
clotrimazole
nystatin
Oral 2nd line for refractory candidiasis
fluconazole
IV tx for BAD candidiasis
amphotericin B
EBV classification:
Herpesviridae
DS DNA
Linear
enveloped
H. pylori gram stain?
G -
H. pylori shape?
flagellated helix shaped rod
H. pylori O2 affinity?
microaerophillic
**requires oxygen to survive, but requires environments containing lower levels of oxygen than are present in the atmosphere
H. pylori
Catalase/Oxidase ?
positive
Characteristic of H. pylori elevating local pH to allow survival?
Urease +++++
Two H. pylori disease causing mechanisms:
- Toxin production
2. Host immune response
How does H. pylori get through low pH lumen quickly?
excellent flagella based motility
H. pylori toxin causing leakage of Ca++ from epithelial cells:
VacA
H. pylori toxin that gets into cytosol and causes problems:
CagA
How does CagA get into epithelial cells?
Type 4 secretion system
Two best characterized VFs of H. pylori?
VacA – pore forming, leaks Ca++
CagA – cystosolic troublemaker
Three steps to forming an ulcer:
- Attract inflammatory cells
- Inflammatory cells can’t kill pathogen
- Host damages self by continual ineffective immune response
Triple therapy for H. pylori
clarithromycin
amoxicillin
PPI
Gold standard Dx for H. pylori:
Endoscopy
Tests good for Dx and confirmation of cure of H. pylori:
- Breath test
senses CO2 from urease rxn
- Stool antigen test
Cancer associated with H. pylori with good prog after abx?
MALT lymphoma
B-cell Tumor of the mucosal associated lymphoid tissue
Cancer of stomach epithilium from H. pylori?
gastric carcinoma