Exercise 8: Vancomycin Sensitivity and Potassium Hydroxide

Question 1

What does KOH stand for?

Answer 1

potassium hydroxide

Question 2

How does the KOH test work?

Answer 2

it causes lysis of the Gram- NEGATIVE organisms, resulting in the release of their DNA. this leads to stringing which is apparent right after mixing the 3%KOH solution

Question 3

What is vancomycin?

Answer 3

an antibiotic

Question 4

Which gram (-/+) are susceptible or resistant to the vancomycin?

Answer 4

• gram positive are susceptible

- gram negative are resistant

Question 5

What is the advantage of doing all three tests together?

Answer 5

• getting more accurate results

Question 6

Susceptible Def:

Answer 6

an organism is sufficiently killed/inhibited by an antibiotic

Question 7

After the vancomycin test what will appear with the gram + discs?

Answer 7

• a ZONE OF INHIBITION

Question 8

Does the KOH or the Vancomycin test provide the quickest results?

Answer 8

• the KOH test provides the fastest
• the Gram-positive is #2
• the Gram negative is #3