Biochemical catalase test principle and interpretations (All catalase positive organism)

Catalase Test Staph Strep

The Catalase biochemical test is used to differentiate those bacteria that are able to produce the enzyme catalase from non catalase producing bacteria.This test is mostly used for the differentiation of Catalase postive staphylococci from catalase negative streptococci 

Principle of Catalase test

There are two methods involved in carrying out catalase test :

The Tube and Slide method.

  • The enzyme catalase produced by catalase positive bacteria acts as  a catalyst in the breakdown of Hydrogen peroxide to Oxygen and water.The bacteria that contain this enzyme are usually aerobes or facultative anaerobes
catalase reaction
catalase reaction
  • Bubbles of oxygen are released when a catalase positive bacteria is present

Noting that the isolated culture should not be more than 24 hours old

Materials required for Catalase test

  • 3 % Hydrogen peroxide
  • Sterile applicator stick or glass rod (Don’t use a Nichrome wire loop)
  • Inoculum or culture plate
  • Slide if using the slide method
  • Test tube if using the Tube method

Procedure of Catalase test (Slide Method)

  • On a clean slide add 1-2 drops normal saline
  • Using a sterile wooden stick or glass rod,remove several colonies of the suspected organism and mix with the normal saline on the slide
  • Add a 2 – 3 drops of 3% Hydrogen peroxide
  • Observe for immediate bubbling
Catalase slide test (Positive with active bubling )
Catalase slide test (Positive with active bubling )


  • When performing the slide method;Hydrogen peroxide should be added to the organism suspension not the organism added to hydrogen peroxide to avoid risk of possible  from active bubbling contamination.
  • Care must also be taking when testing an organism cultured on blood agar or Tryptone soya agar with blood supplement because the enzyme catalase is present in red blood cells which may result to false positive results.
Also read  Laboratory Diagnostic of Naegleria fowleri and Treatment

Procedure of Catalase test (Tube Method)

  • In a sterile test tube,add about 1-2 ml of 3% Hydrogen peroxide
  • Using a sterile wooden stick or glass rod,remove several colonies of the suspected organism and immerse in the hydrogen peroxide solution in the tube
  • Observe for immediate bubbling
Catalase tube test
Catalase tube test

Interpretation of Catalase test observation

Active BubblingCatalase Positive organisms
No BubblesCatalase Negative Organism

Catalase positive and Negative Organism

Catalase positiveCatalase Negative
Staphylococci species Streptococcus species
Micrococci species Enterococcus species
Listeria species
Corynebacterium diphtheriae
Burkholderia cepacia
Nocardia species
Citrobacter species
Escherichia coli
Klebsiella species
Shigella species
Yersinia species
Proteus species
Salmonella species
Serratia species
Pseudomonas species
Mycobacterium tuberculosis
Aspergillus species
Cryptococcus species
Rhodococcus equi
Enterobacter species

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About the Author: Arthur Westmann

DEFFE ARTHUR (AMOEBAMANN) is the founder and author of MLTGEEKS and MLTEXPO.He’s from Cameroon and is currently a Final year State Medical Laboratory Technician (MLT MA). Beyond lab works, he’s a passionate internet user with a keen interest in web design and blogging. Furthermore He likes traveling, hanging around with friends and social networking to do in his spare time.

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