Micro FINAL – Anaerobes – Flashcards
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| Best place to grow strict anaerobes? |
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| 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. |
