question
What is a selective medium
answer
a medium that allows for the growth of only one type of organism by inhibiting the growth of others
question
What is a saprophyte
answer
a plant, fungus or microorganism that lives on dead or decaying organic matter
question
Yellow coloration of a Snyder's agar tube with saliva indicates what?
answer
the presence of sugar fermenting lactic acid bacteria that can contribute to cavities.
question
What is the microbe associated with dental caries according to the lab manual?
answer
Lactobacillus acidophilus
question
Which medium is selective for fungi?
answer
Sabouraud dextrose agar
question
What is a medium selective for lactobacilli?
answer
Rogosa SL agar
question
T/F - Acetic acid (concentrated vinegar) is present in Rogosa SL in order to make it selective for lactic acid bacteria because they can tolerate the low pH whereas most other bacteria cannot.
answer
True
question
what is the relationship between the number of lactobacilli in the oral flora and the incidence of dental caries?
answer
The higher the incidence of lactobacilli in the mouth, the higher the incidence of dental caries (cavities)
question
how do you adjust lactobacilli counts in bacteria/ml of saliva?
answer
Colonies on plate x dilution factor = bacteria/ml in saliva.
question
what is a Sabouraud dextrose agar?
answer
selective medium for fungi, inhibits most bacteria with low pH
question
the acid produced by the fermentation of sugar by the Lactobacilli breaks down what on the teeth?
answer
dentin
enamel
enamel
question
Certain ____________ are also acid producers
answer
streptococci
question
what are the most important factors associated with dental caries?
answer
oral hygiene
fluoridation
regular dental care
fluoridation
regular dental care
question
What does the yellow color indicate when using the Synder method?
answer
acid
question
what does Rogosa SL agar use to inhibit the growth of other oral flora?
answer
Glacial acetic and other agents
question
on the mold slide why can't it be observed properly?
answer
bc of the Opaqueness of the medium & the destruction of the mold structure in preparing the wet mount.
question
what stain was used on the fungal wet mount
answer
lactophenol cotton blue
question
_______________: is a selective medium that allows for the growth of fungi (molds & yeasts).
This medium inhibits most bacteria due to its acidic pH; its acidic in nature, allowing for slower growing fungi a change to grow.
This medium inhibits most bacteria due to its acidic pH; its acidic in nature, allowing for slower growing fungi a change to grow.
answer
Sabouraud Dextrose Agar
question
Why are there variations of the medium—Sabouraud Dextrose Agar?
answer
Because 'Sabouraud Dextrose Agar' usually has an low pH (or acidic pH), which inhibits most bacteria & fungi.
A variation, would include a pH that is neutral (in nature), in which bacteria would be inhibited by antibiotics in the medium, and not affect fungi growth.
A variation, would include a pH that is neutral (in nature), in which bacteria would be inhibited by antibiotics in the medium, and not affect fungi growth.
question
______________: is a medium that allows for the growth of one type of organism.
What is an example?
What is an example?
answer
Selective Medium
Sabouraud Dextrose Agar
Sabouraud Dextrose Agar
question
_______________: is a plant fungus or microorganism that is living & feeding on dead or decaying organic matter.
answer
Saprophyte
question
Is saprophytic fungi [pathogenic or not pathogenic]?
answer
Some can be pathogenic.
The prognosis of recovery from these infections is not good.
The prognosis of recovery from these infections is not good.
question
What microbe is most commonly associated w/ dental caries?
answer
Lactobacillus acidophilus
question
_____________ is an organism that does fermentation of sugar, producing lactic acid, which breaks down enamel & dentin.
answer
Lactobacillus acidophilus
question
What is the medium selective for the growth of lactobacilli?
answer
Rogosa SL agar
question
________________: is a medium that uses glacial acetic & other agents to inhibit the growth of oral flora, but will not affect the growth of lactobacilli.
answer
Rogosa SL agar
question
What acid is commonly produced by lactobacilli?
answer
Lactic acid.
question
The prime cause of dental caries is ______________.
answer
Lactic acid
question
The [lower or higher] the incidence of Lactobacilli in oral flora, the [lower or higher] the incidence of dental caries.
answer
Higher, higher
question
List 2 types of bacteria that produce acid, which cause tooth decay.
answer
Lactobacilli
Streptococci
Streptococci
question
What are important factors associated w/ dental caries? (List 3)
answer
Oral hygiene
Fluoridation
Regular dental care
Fluoridation
Regular dental care
question
Dental caries susceptibility can be determined by ________________
answer
Incidence of lactobacilli
question
List 2 methods used to study Lactobacilli activity in the mouth.
answer
Standard plate count
ML Snyder
ML Snyder
question
ML Snyder Method uses, what for the medium?
answer
Snyder's test agar (Tube)
question
Which method is simpler, the 'Standard Plate Count' or 'ML Snyder'?
answer
ML Snyder
question
Why is the ML Snyder method simpler than the Standard Plate Count?
answer
The tube of agar is simply read for a color change.
question
In ML Snyder method, what does it mean if the agar stays its original color green?
answer
Susceptibility to caries is low.
question
In ML Snyder method, what does it mean if the agar become more yellow?
answer
Susceptibility to caries increases.
question
In ML Snyder method, the color yellow indicates ____________.
answer
Acid
question
What medium is used for the Standard Plate Count?
answer
Rogosa SL agar (tubes)
question
Rogosa SL agar uses _______________ & other agents to inhibit the growth of ____________.
answer
Glacial Acetic Acid, Oral Flora
question
Rogosa SL agar does not affect the growth of ________________.
answer
Lactobacilli
question
Which agar is very slow to solidify, there for should not be inverted?
answer
Rogosa SL agar
question
Which exercise uses Diluted saliva?
Inoculates into which medium?
Inoculates into which medium?
answer
Standard Plate Count
Rogosa SL agar
Rogosa SL agar
question
Which exercise uses Undiluted saliva?
Inoculates into which medium?
Inoculates into which medium?
answer
ML Snyder method
Synder's Test agar
Synder's Test agar
question
Which medium uses 'Glacial Acetic Acid' to inhibit the growth of Oral Flora?
answer
Rogosa SL agar
question
Which medium does not affect the growth of Lactobacilli?
answer
Rogosa SL agar
question
When liquefied, _______________ agar does not become clear.
answer
Rogosa SL agar
question
What types of dye is used in the experiment "Slide Culture Experiment"?
answer
Lactophenol Cotton Blue
question
Name the medium that is selective for culturing of molds?
answer
Sabouraud Dextrose Agar
question
In the mold culture slide, we are growing the mold on the slide in order to
answer
Better observe the way the mold grows without destroying the structure.
question
We are trying to detect the presence of which organism by using the Rogosa SL agar?
answer
Lactobacilli
question
We use Snyder's test agar to detect the presence of lactobacilli. How is the presence of these organisms detected by the agar?
answer
Initially the agar is green, but will change color towards yellow if lactobacilli are present.
question
Why are we using sterile saline?
answer
To make dilutions of the saliva before plating.
question
What inhibits the growth of bacteria in the Sabouraud dextrose agar?
answer
It has an acidic pH.
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