catalase test presented by dr mohan singh dhakad

catalase test principle , methods and interpretation

1. Catalase test Presented by Dr mohan singh dhakad Pg resident

2. Catalase Test Overview Catalase is an enzyme that catalyzes the breakdown of detrimental hydrogen peroxide (H 2 O 2 ) into oxygen and water. H 2 O 2 is a toxic byproduct produced by metabolic reactions occurring in the presence of water and oxygen and is toxic to cells Thus enzymes, such as catalase, are necessary to break down H 2 O 2 in microorganisms that live in environments where oxygen is abundant

3. The catalase test is used to detect the presence of catalase in certain bacteria, such as staphylococci. The presences of catalase is indicated by oxygen bubbles that are produced upon the addition of hydrogen peroxide, yielding a positive result. If no bubbles are present, it is presumed that catalase is not present (or is not functional). Examples of bacteria that do not produce catalase are streptococci.

4. Catalase Test Protocol Interpretation: Bubbles will form around the organism on the loop if catalase is produced Procedure: 1. Start with a clean microscope slide and place a drop of hydrogen peroxide on it . 2 . Using an inoculating loop, remove some of your assigned organism and put the loop with the organism on it into the drop of hydrogen peroxide. Do not stir. 3. Observe the drop of hydrogen peroxide. Fig. 1 Catalase test on Staphylococcus aureus. In this image, H 2 O 2 is applied directly to bacterial colonies. The bottom image represents a positive result for catalase.

5. Tube catalase test

6. Positive Catalase Reaction Produced by Staphylococcus aureus
A positive catalase reaction produced by Staphylococcus aureus. Using a wooden applicator stick, a small amount of organism from a well-isolated 24-hour colony was collected and placed into the test tube containing hydrogen peroxide. A positive result is indicated by bubbling.  American Society For Microbiology ©

7. Summary The catalase test is used to detect the presence of catalase in certain bacteria, The presences of catalase is indicated by oxygen bubbles that are produced upon the addition of hydrogen peroxide, yielding a positive result. https://microbenotes.com/catalase-test-principle-procedure-and-result-interpretation/

8. Other Example of catalase positive Enterobacteriaceae Vibrionacae pseudomonadacae