Term
| Give three examples of normal residents in the mouth. |
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Definition
| Anaerobic spirochetes and vibrios, and staphylococci. |
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Term
| Give three examples of normal residents in the eye conjunctiva. |
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Definition
| Staphylococci,streptococci, and neisseriae. |
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Term
| Give three examples of normal residents in the skin. |
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Definition
Staphylococci (mainly S. epidermidis), streptococci (α-hemolytic, nonhemolytic), enterococci, yeasts, and fungi. |
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Term
| Give three examples of normal residents in the intestinal tract (upper tract). |
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Definition
| lactobacilli and enterococci |
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Term
| Give three examples of normal residents in the lower intestinal tract. |
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Definition
96-99% anaerobes: genera Lactobacillus, Clostridium, Streptococcus. 1-4% aerobes: enterococci, and small numbers of Proteus & Pseudomonas. |
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Term
| Give three examples of normal residents in the genitourinary tract. |
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Definition
Staphylococci, streptococci, lactobacilli, gram negative enteric bacilli, clostridia, etc. |
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Term
| List one disease associated with Staphylococcus aureus. |
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Definition
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Term
| List one disease associated with Staphylococcus epidermidis. |
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Definition
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Term
| List one disease associated with Staphylococcus saprophyticus. |
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Definition
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Term
What do each of these results tell you about the organism: 1) No growth on a mannitol salt (MSA) plate 2) Organisms grew on a mannitol plate; plate became yellow: 3) A rose halo appeared around the colony on a DNAse test plate: |
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Definition
1) no growth on an MSA plate = not a salt-tolerant organism 2) growth on an MSA plate that turned plate yellow = salt tolerant organism can ferment mannitol 3) rose halo on DNAse plate = positive for DNA hydrolysis. |
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Term
| Is the test used in lab a direct or an indirect ELISA test? How did you know? |
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Definition
| Indirect because we were looking to detect the presence of HIV antibodies. |
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Term
| In the indirect test what body fluid would you obtain from the patient in order to perform the test? |
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Definition
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Term
| In the direct test what would you obtain from the patient to perform the test? |
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Definition
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Term
| What is the role/purpose of HIV antigen in the ELISA assay? |
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Definition
| It is there so that antibodies (if present) can interact with the antigens, allowing us to test for the presence of the antibodies. |
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Term
| What is the role/purpose of IgG antibody in the ELISA assay? |
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Definition
| IgG antibody is there to act as a positive control. |
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Term
| What is the role/purpose of Anti-IgG antibody in the ELISA assay? |
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Definition
| This is used to detect the presence of the IgG antibody in Donors 1 and 2, as well as in the positive control. |
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Term
| What is the role/purpose of horseradish peroxidase in the ELISA assay? |
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Definition
This was used as an enzyme that is linked to the anti-IgG antibodies. The enzyme would bind to a substrate, and if the anti-IgG antibody was present, you'd see a brown precipitate. If no anti-IgG antibody is present, then the substrate would have nothing to bind to, and you'd get no color.
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Term
| What is the role/purpose of PBS buffer in the ELISA assay? |
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Definition
| The PBS buffer was used to wash excess antigen and antibodies from wells, and as a negative control. |
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Term
| What is the role/purpose of substrate reagent in the ELISA assay? |
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Definition
| The substrate reagent contains H2O2 and aminosalicylate. The horseradish peroxidase in the secondary antibody would react with this and indicate the oxidation of salicylate. If it salicylate is oxidized, you'd see brown, which also indicates positive for antibody. |
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Term
| Why is the ELISA test so sensitive? |
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Definition
| ELISAs are very sensitive due to highly specific antibody – antigen interaction. |
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Term
| What do the circular precipitin rings represent? |
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Definition
| The rings represent the reaction of soluble antigen with the antibodies as the antigen diffuses away from the well into the agarose. |
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Term
| Why do the ring sizes change until equilibrium is reached? |
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Definition
| The antigen diffuses out of the well until it there is a zone of equivalence between antigens and antibodies. This is where the antigen and antibody ratio is roughly equal in concentration. |
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Term
| Predict the results if a very low concentration of antigen were loaded in a well. What would happen if not enough antibody was incorporated? |
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Definition
If there was a low concentration of antigen loaded in a well, and not enough antibody was incorporated into the agarose, you would see no pricipitin ring (if [antigen] is greater than [antibody]). Or, a ring of very small diameter may be seen if there is enough antibody to equate to the low concentration of antigen (zone of equivalence is met). |
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Term
| Compare and contrast RID and Ouchterlony. |
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Definition
RID and Oucherlony are similar because they both use zones of equivalence and the use of precipitants. RID uses a plate of agarose + antibodies with the use of wells, and the diffusion of antigen. The precipitin rings show zone of equivalence. RID is a quantitative method that can be used to determine unknown antibody or antigen concentrations. Ouchterlony uses test tubes where visible zone of equivalence is seen as precipitate in solution. It is a qualitative method to indicate presence of antigen or antibody.
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Term
| Distinguish antibiotics from synthetic drugs. |
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Definition
Antibiotics = Synthesized and secreted by some true bacteria, actinomycetes, and fungi. • Some now made in labs; origins in living cells. Synthetic drugs = All synthesized in a lab. |
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Term
| Name one example of antibiotics. |
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Definition
| Streptomycin = interferes with protein synthesis. |
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Term
| Give one example of synthetic drugs. |
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Definition
| Sulfadiazine (sulfonamide) = Bacteriostatic |
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Term
| When using the Kirby-Bauer test why are the areas of clearing around the disks different diameters even though both might be considered sensitive for that organism? |
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Definition
The diameters may be different because the rate of diffusion of the disks into the media may differ, and/or the degree of the microbe's sensitivity to the antibiotics may vary. Both however, may be still be considered effective against the microbe (based on charts of previous tests). |
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