Exam 3 (Oral Bacteria) Flashcards
What is the common target of microbes in molecular classifications?
16s rRNA subunit (GOLD STANDARD)
How do 16s rRNA subunits compare between bacterial species?
conserved regions remain unchanged along the evolutionary tree while variable regions can be used to differentiate bacterial species
What has the higher concentration of bacteria? Skin or dental plaque?
Dental plaque (one of the highest)
What three things make up the acquired pellicle on tooth surfaces?
- molecules in saliva (predominant)
- material shed from bacterial cell surfaces
- polymers from GCF
____________ are usually the first species to adhere to the pellicle. _______________ are both important adhesins that bind salivary glycoproteins, other bacteria, and calcium.
- Streptococcus (goms)
- Antigen I and II
After streptococci populate the pellicle, other species attach via ____________. Important species at this stage are…. (three).
-coaggregation
- Actinomyces naeslundii
- Actinomyces viscosus
- Streptococcus gordonii
After other species begin to coaggregate, the microenvironment supports additional species like…. (two)
- Strep. mutans
- Strep. sobrinus
As the biofilm develops, __________ begin producing _________ which polymerizes the glucose moiety of sucrose into _______. They are branched- polysaccharides with alpha 1->6 and 1->3 linkages.
- Streptococci
- glucosyltransferases
- glucans
In dental plaques, bacteria are bound to each other and do a matrix of _________.
glucans
Late colonizers of dental plaques include obligate anaerobes such as….. (three)
- Prevotella melaninogenicus
- Prevotella oralis
- Veillonella spp.
3 altered properities of bacteria in a biofilm
- Upregulated genes for extracellular polysaccharide synth
- Incr resistance to antimicrobial agents (numbers, enzymes, slow growth, novel phenotypes)
- metabolic interaction between closely spaced bacteria
What causes a dental biofilm to begin creating caries?
-breakdown of homeostasis alters bacterial composition
reduced saliva flow or increase in sucrose
Acids formed by biofilms
lactic acid (as well as acetic and formic acid)
Two reasons dentin is more easily attacked and colonized by bacteria?
- less mineralized
2. protein rich so many different bacteria can colonize
_________ and ________ are the likely pathogens of root caries by __________ species are also involved.
- Strep mutans
- Lactobacilli
- actinomyces
Pathogenic bacteria are able to more rapidly ferment sugars because of their ________ systems
PEP-PTS (group translocation)
Bacterial enzymes have more ______ pH optima. Bacterial cells produce ________________ to protect cell contents in acidic conditions.
- acidic
- acid-stress response proteins
What are the two major substrates for alkali production via the generation of ammonia?
Urea and arginine
What two enzymes help produce alkali in noncariogenic bacteria?
Urease and Arginine Deiminase
Strep. mutans
What does SpaP (antigen B, I, II, P I) do?
adherence to saliva coated tooth surfaces and salivary agglutinin
Strep. mutans
produces alpha 1-3 and 1-6 linked glucose polymers
Glucosyltransferases (GtfB,C,D)
Strep. mutans
What is GbpA, B, C?
Glucan binding proteins
In Strep. mutans, what enzyme produces beta 2-1 and 2-6 linked polymers for extracellular polysaccharide storage?
Fructosyltransferase Ftf
Fructanase and intracellular polysaccharides both……
extend the depth and duration of acidification
Strep mutans
What virulence factor is critical for the cell’s acid tolerance?
ATPase
What plaque hypothesis involves inflammatory disease of the gums?
Nonspecific plaque hypothesis
What plaque hypothesis involves infection of the gums?
Specific plaque hypothesis
The nonspecific plaque hypothesis refers to the ______________ of dental plaque. Molecules such as _______, ________ (like butyrate, propionate), and ________ (like methyl mercaptan). Treatment dictates that ______________________.
- bacterial complexity
- LPS
- volatile fatty acids
- sulfides
- flora be suppressed continuously or periodically
Aggregatibacter actinomycetemcomitans associated with the specific plaque hypothesis produces a leukotoxin that ____________. LJP is a treatable infection with local antimicrobial agents and systemic ___________.
- inhibits neutrophils
- tetracycline
____________ (or ANUG) is caused by what two pathogens and is controlled with antibiotic mouth rinses as well as systemic ___________?
- Acute necrotizing ulcerative gingivitis
- spirochetes and Fusobacterium nucleatum
- metronidazole
The three main pathogens associated with the polymicrobial infection of the specific plaque hypothesis?
- Porphyromonas gingivalis
- Tannerella forsythia
- Treponema denticola (and other spirochetes)
What is the dysbiotic keystone pathogen of the mouth?
Porphyromonas gingivalis
Three virulence factors of Aggregatibacter actinomycetemcomitans?
- Leukotoxin
- Invasins
- Bacteriocin (kills competing bacterial species)
What virulence factor of Aggregatibacter actinomycetemcomitans gives it resistance to phagocytosis and increases bone resorption?
Capsular polysaccharide
What virulence factor Aggregatibacter actinomycetemcomitans causes hydrolization of the host cell membrane?
Phospholipase C
4 virulence factors of Fusobacterium nucleatum?
- Capsule
- Hemolysin
- Leukocidin/leukotoxin
- Superoxide dismutase
3 virulence factors of Prevotella intermdia?
- Dark pigment (protects from toxic oxygen)
- Collagenase, hyaluronidase, protease (degrade tissue)
- Hemolysin (helps acquire iron)
Dentoalveolar infections are _________ infections associated with the teeth and surrounding structures.
pyogenic
Endodontic infections are ________________ infections that are ____________.
- endogenous
- opportunistic
Bacterial cultivation means ____________ with the two most commonly cultivated from root canal infections being…..
- grown in the lab on artificial growth media
- bacteroides and prevotella
What are the three methods of dentoalveolar abscesses?
- spread from carious lesion
- through periodontal membrane and accessory root canals
- anachoresis via pulpal blood supply during bacteremia from extraction of other tooth.
2 facultative anaerobes of dentoalveolar abscesses.
- Streptococci
2. Actinomyces
4 obligate anaerobes of dentoalveolar abscesses.
- Peptostreptococcus spp.
- Porphyromonas gingivalis
- Prevotella
- Fusobacterium nucleatum
What is Ludwig’s Angina?
spreading bilateral infection of sublingual and sub mand spaces (spreading in fascial spaces rather than abscess)
Ludwig’s Angina is a _______ ___________ infection.
-mixed endogenous
What four organism are associated with supportive osteomyelitis of the jaws?
- anaerobic streptococci
- porphyromonas
- prevotella
- fusobacteria
What disease and bacteria is associated with granulomatous infections of the cerficofacial region with sulphur grnaules?
Cervicofacial actinomycosis
4 oral manifestations of syphilis infections? Which two are congenital?
- *Hutchinson’s incisors (notched)
- *mulberry molars
- primary and secondary syphilis lesions
- gummas
Most common pathogen to infect salivary glands?
-staphylococcus
7 diseases associated with oral bacteria
- infective endocarditis
- disseminated intravascular coagulation
- nephritis
- Rheumatoid arthritis
- Behcet’s disease
- atherosclerosis
- Low-birth-weight infants
What protein on the surface of streptococci is responsible for infective endocarditis?
PAAP- platelet aggregation-associated protein
Antibodies to microbial ________ can cross react with human _____. If immune complexes are deposited on the arterial wall as in _________ and on joints as in ______, this mimicry can lead to systemic disease.
- heat shock proteins
- HSP
- atherosclerosis
- arthritis
The PAAP of this microbe has an epitope of Type II collagen which is associated with autoimmune arthritis.
S. sanguinis
Inflammatory reactions in the gingiva can lead to elevated levels of systemic ______ and _____ which can exacerbate existing disease.
TNF-alpha
IL-1beta
Peptidoglycan is recognized by TLR_?_
TLR2
Lipopolysaccharide is recognized by TLR_?_ and TLR_?_ and TLR_?_
TLR4 and TLR6 and TLR10
Lipoteichoic acid is recognized by TLR_?_
TLR4
The main _________ is HBD-1. These are ______ that work by…..
- defensin
- small peptides
- forming pores in bacterial membranes (susceptible due to high phospholipid content)
These form a selectively permeable layer on the mucous membrane. They are made up of ________ and ______.
mucins
- glycoproteins
- carbohydrates
How much saliva is secreted per day?
0.5 - 1.5 liters/day
MG1 and MG2 are ______ that aggregate and clear microbes via ________________.
mucins
-lecithin like interactions
Action of lysozyme in saliva on microbes
degrades peptidoglycan by cutting bond between NAG and NAM (muramidase)
