Term
| What two methods are used to rapidly predict the Gram staining reaction of a bacterial isolate? |
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Definition
| Ryu/KOH technique, Vanc Sensitivity test |
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Term
| What are the advantages of the Ryu/KOH Technique and the Vanc Sensitity Test in rapidly predicting the Gram staining reaction of a bacterial isolate? |
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Definition
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Term
| What are the disadvantages of the Ryu/KOH technique and the Vanc Sensitivity Test? |
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Definition
| morphology (rod, cocci, etc) cannot be predicted; mutant and/or atypical strains of bacteria could give a misleading result; they require pure cultures |
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Term
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Definition
| A method in which a sterile loop is used to transfer part of a bacterial colony to a glass slide. A much larger cell mass than with staining is used. The sample is not spread into a smear as with staining. A drop of KOH is added and mixed with the sample using the loop. The two are mixed and stirred together for approximately 30 seconds. The test is focused on whether the growth is now "stringy." The alkaline solution dissolves the gram negative outer envelope, causing the bacteria to become sticky and tacky, thus generating a slimy emulsion. A positive KOH test is stringy bacteria, predicting a gram negative stain result. This test is only valid if significant stringiness is observed within one minute of mixing. |
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Term
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Definition
| An antibiotic that blocks peptidoglycan cross-linking. |
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Term
| How do gram positive organisms react to vancomycin? Gram negative? |
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Definition
| Gram positive tend to be sensitive, Gram negative tend to be resistant. |
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Term
| What method can be used to determine sensitivity to Vancomycin? |
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Definition
| Vancomycin Susceptibility Test |
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Term
| Any size zone of inhibition using a 5 microgram vancomycin disk is considered "_____," while lack of inhibition is considered "_____." |
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Definition
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Term
| What is a powerful and commonly used straining technique aside from Ryu/KOH technique and vycomycin susceptility test? |
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Definition
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Term
| Who developed the Acid-Fast stain technique and when? |
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Definition
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Term
| Why is heat applied to the preparation to speed up and intensify the staning of the bacterial cells? |
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Definition
| Because of the rather impermeable and lipid-rich nature of the cell walls of mycobacteria to the stain. |
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Term
| Acid-fast stain is an important staining procedure for the detection and identification of bacteria that belong to the genus _____. |
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Definition
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Term
| Acid-fast stain is useful for staining pure cultures of Mycobacterium, but is also applicable for staining bacteria found in the _____, _____, and _____, of infected individuals. |
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Definition
| saliva, tissues, and blood |
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Term
| The Gram Stain is unreliable with Mycobacteria, thus they are termed _____. |
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Definition
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Term
| Explain the Acid-Fast stain procedure. |
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Definition
Prepare thin smears of bacteria to be stained.
2. Air dry and heat fix the smears.
3. Place the fixed smear in the slide holder.
4. Place a piece of biulous paper over the smear.
5. Flood the preparation with carbol-fuchsin staining solution and allow to remain at room temp. for one minute.
6. Heat the preparation by passing the slide repeatedly through the flam of a Bunsen burner until slight steaming is observed.
7. Maintain steaming temperature without boiling for five minutes by passing preparation through flame as needed. Add more staining solution as needed to prevent drying out.
8. Allow to cool. Remove bibulous paper by lifting straight up without dragging. Rinse with water.
9. Decolorize with 3% Hcl in ethanol.
10. Rinse with tap water.
11.Cover smear with methylene blue counterstain solution for one minute.
12. Rinse with tap water, blot dry, and examine with oil immersion objective.
13. Remove oil, label and store as suggested for gram stained preparations. |
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Term
| Bacteria that are acid-fast retain the carbol fuchsin dye and appear as _____ rods while bacteria that do not retain the primary stain appear as _____ rods, the color of the secondary stain. |
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Definition
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