Micro FINAL – Anaerobes – Flashcards

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question
Best place to grow strict anaerobes?
answer
Anaerobic glove box.
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Aerotolerant and moderate anaerobes should be grown in what?
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Anaerobic-gas pack or biobag.
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Microaerophiles should be grown in what?
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CO2 incubator or candle jar.
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What is Eh?
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Redox potential measured in microvolts.
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High Eh means what?
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The substance is oxidized.
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Low Eh means what?
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The substance is very reduced (electron rich).
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What microbes have the highest Eh?
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Obligate aerobes.
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What microbes have the lowest Eh?
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Strict anaerobes.
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What microbes have the second highest Eh?
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Microaerophiles.
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Names of two redox indicators:
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Resazurin.
Methylene Blue.
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Resazurin results:
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Colorless - anaerobic conditions.
Pink - oxygenated conditions.
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Methylene blue results:
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Colorless - anaerobic conditions.
Blue - oxygenated conditions.
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The typical redox indicator in an anaerobe jar?
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Methylene blue.
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Advantages of an anaerobe jar:
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Convenient.
Inexpensive.
Mobile.
Doesn't take up much space.
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Disadvantages of an anaerobe jar:
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Limited space for plates and tubes.
Can't see plates without opening the system.
To work on the microbes they are exposed to oxygen.
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Gas generator of an anaerobe jar contains what substances?
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Sodium borohydrate.
Sodium bicarbonate.
Citric acid.
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Do you add water to the gas generator or an anaerobe jar?
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Yes - H2 and CO2 will be released.
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Redox indicator of a biobag:
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Resazurin.
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Advantages of a biobag:
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Inexpensive.
Mobile.
Doesn't take up much space.
Can see growth without opening system.
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Disadvantages of a biobag:
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Limited space for plates and tubes.
To transfer or stain, microbes are exposed to oxygen.
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Advantages of an anaerobic glove box:
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Lots of room.
Can see the plates.
Can work on microbes without oxygen exposure.
Never gets exposed to oxygen - strict anaerobes can be grown.
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Disadvantages of an anaerobic glove box:
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Expensive to set up and maintain.
Takes up lots of space.
Gets hot.
Hands get sweaty, need your own cotton liners.
Working for long periods of time.
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Where are aerobic habitats?
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Everywhere - especially soil.
Mucus membranes of animals.

Humans:
Oral cavity.
Colon.
Genitourinary tract.
Skin.
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Blood flow in an anaerobic infection is typically ______:
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Poor or absent.
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True or false: Anaerobic infections are typically poly-microbic?
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True. Anaerobic infections typically contain anaerobes, facultative anaerobes and microaerophiles.
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Best specimen acquisition of anaerobes:
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Aspirates and biopsies.
(Try to avoid normal flora)
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Good specimen choices for anaerobe samples:
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Body fluids.
Exudates from deep abscesses.
Transtracheal aspirates.
Direct lung aspirates.
Suprapubic punctures.
Tissue biopsies.
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Least desirable specimen sample for anaerobes:
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Swabs - often rejected.
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Anaerobe specimen transportation should always be in a...?
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Closed system - excluding oxygen and avoiding drying.
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Is a syringe or needle acceptable for anaerobe transportation?
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No. Due to sticks/injuries.
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Clues for anaerobic infections:
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Foul smelling odor*
Purulent appearance - presence of pus.
Necrotic tissue with gas.
Presence of sulfur granules.
Microbe present in primary Gram smear.
Does not grow aerobically.
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Are primary Gram smears required for anaerobes?
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Yes.

Use methanol fixation instead of heat.
Gram's iodine is mixed with Crystal Violet.
Use modified Safranin or extend counterstaining time.
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Anaerobic media:
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Bi-plate: AnaBAP/BBE (Anaerobic Blood Agar Plate Bacteroides Bile Esculin)

Thioglycollate Broth.

KV Agar (Kanamycin-Vancomycin)

Chopped Meat Broth.

Egg Yolk Agar.
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How long should Egg Yolk Agar plates be kept?
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Up to 7 days due to delayed reactions.
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"Oil on water sheen" - What media? Why does it happen?
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Egg Yolk Agar.

Happens due to lipase breaking down fats in egg yolks, causing iridescent sheen.
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Lecithinase production - what media? why does it happen?
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Egg Yolk Agar.

Happens because lecithinase degrades lecithin in egg yolks - produces an insoluble, opaque precipitation in the media surrounding growth.
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