Term
| What is a specific example when the timeliness of a specimen collection is important? |
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Definition
| Smears for malaria diagnosis should be collected at different times during the day because parisitemia can be intermittent |
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Term
| When should you NOT collect a microbial specimen from a patient. |
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Definition
| You would not want to collect a sample from the patient AFTER antimicrobial therapy. Please don't make me explain this. |
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Term
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Definition
| A General Purpose agar that can isolate microbes based on if they somewhat break down the agar, completely break it down, or can't break it down at all (alpha, beta, gamma, respectively) |
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Term
| Describe Chocolate Agar and an example of a microbe that loves it |
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Definition
| Chocolate agar is like blood agar but all the RBCs are lysed. Bugs like Haemophilus and Neisseria thrive in this medium. Thayer-Martin = chocolate + antibiotics. It is used to detect N. gonorrhoeae |
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Term
| You are working in a lab and need to use a medium that is selective for S. aureus, what would you choose? |
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Definition
| Mannitol-salt agar has a high [salt] and inhibits most bugs. If S. aureus is present the agar turns from red to yellow. |
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Term
| What organisms is MacConkey agar selective for? What carbs does it have? What microbes does it inhibit? |
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Definition
| Selective for gram negative organisms. It only has Lactose. Inhibits gram (+) and hemophilus and neisseria. Lactose fermentation = red/pink. |
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Term
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Definition
| Eosin Methyylene Blue show lactose fermenters as blue-black, possibly with a metallic sheen. |
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Term
| What is Bile esculin agar selective for? How is it determined visually? |
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Definition
| Bile esculin agar is selective for Group D Strep and Enterococcus. These bugs convert esculin to exculitin which reacts with iron to produce a black precipitate. |
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Term
| You suspect a patient of yours has Salmonella poisoning. What agar would you use? Why? |
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Definition
Hektoen enteric (HE) agar isolates enteric pathogens.
Fermenters = yellow-pink.
Non-fermenters = green or clear.
H2S-producers = black (salmonella) |
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Term
| Your patient comes in complaining of Hot-tub rash and you suspect Pseudomonas aeruginosa. What agar would you place the culture on to confirm? |
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Definition
| Cetramide agar will inhibit most other microbes and shows pseudomonas as blue-green or yellow-green colonies. |
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Term
| Your patient presents with fatigue, mild fever and problems swallowing. You suspect Corynebacterium diphtheriae but you can only choose one agar to grow it on. What would you choose? |
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Definition
| Tellurite agar/Cystine-tellurite agar is selective and differential for C.diphtheriae. The colonies are gray or black with a brown halo. |
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Term
| A salesman comes to your office and he says he's got the "Optimus Prime" of agars. It can colonize different bugs showing up as different colors and can even differentiate MRSA and MSSA. You says, "Homie, that's not new. Its called..." |
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Definition
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Term
| What are two biochemical tests that you can do for bacteria that can be run in minutes? |
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Definition
| Catalase (Hydrogen peroxide to H2O + O2) and Oxidase (presence of Cytochrome C oxidase). Coagulase agglutination test is also rapid |
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Term
| How is Thioglycollate used? How is it read? |
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Definition
| Thioglycollate test allows various amounts of O2 to diffuse to different levels. Obligate aerobes grow at the top. Facultative anerobes grow throughout but more to the top. Aerotolerate anaerobes grow throughout. Strict anaerobes will not grow at the top. |
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Term
| List some ways one can visualize microbes from a smear or sample. |
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Definition
| Wet prep, stained prep, dark field, light field, phase contrast, fluorescence, electron microscopy. |
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Term
| Why is an agglutination test useful? |
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Definition
| It is fast and can be used even if the patient has been treated with antibiotics. |
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Term
| What antibodies can be detected to...detect Hepatitis Virus or dimophic fungi? |
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Definition
| IgG or IgM. These are very sensitive tests but M can only be detected from 7-10 days and G can only be detected 2-4 weeks later. |
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Term
| In immuno assay what technique targets two different epitopes for measure and capture? |
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Definition
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Term
| Which type of test is considered to be objective but is still very useful? |
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Definition
| Indirect Fluroescent antibody |
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Term
| An old, labor-intensive, technically challenging method for detection of antibodies against specific pathogens? |
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Definition
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Term
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Definition
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Term
| What is the difference between Signal Amplification and Nucleic-Acid amplification? |
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Definition
| With signal-amplification a single nucleic acid signal will produce a highly-amplified signal is proportional to the number of copies of the specific nucleic acid. Nucleic-acid amplification is simple PCR...I'm pretty sure. Someone correct me if I'm wrong. |
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Term
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Definition
| Besides the fact that you had to run a million of them in undergrad, they have licensing fees every time you use it. |
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