Question

You are given 2 nutrient broth tubes each containing a pure culture of one of two Gram Positive bacteria. Unfortunately, the labels have washed off and you are asked to determine which tube contains Streptobacillus epidermidis and which tube contains Diplococcus anginosus.

a. Name a technique you would use

b. DRAW the expected results used to sort the 2 tubes. Make sure to label your drawings (which is S. epidermidis and which tube contains D. anginosus)

Answer 1

Answer =

You are given 2 nutrient broth tubes each containing a pure culture of one of two Gram Positive bacteria. Unfortunately, the labels have washed off and you are asked to determine which tube contains Streptobacillus epidermidis and which tube contains Diplococcus anginosus.

a. a technique you would use is microbiological test that is catalase test:

Technique of catalase Test = The basis of this test is enzyme catalase mediates the breakdown of hydrogen peroxide into oxygen & water.

in this test add 1-2 ml of H2O2 solution into a test tube.then using wooden stick or glass rod ,add colonies from from test tube .

observe for immediate bubbling.

After performing this we observed that, the test which contains Streptobacillus epidermidis , the bubbles are produced, because these organisms are catalase positive.

the test which contains Diplococcus anginosus. , the bubbles are not produced, because these organisms are catalase negative

in this way we can differentiate these organisms.

b. DRAW the expected results used to sort the 2 tubes. Make sure to label your drawings (which is S. epidermidis and which tube contains D. anginosus)

Catalase Positive Catalase Negative Streptobacillus epidermidis Bubbles are evolved Diplococcus anginosus No bubbles are released