This test is usedto help in the identification of the organisms which produce the enzyme oxidase. Examples: Pseudomonas, Neisseria, Vibrio and Pasteurella species.
v Principle:-
A colony of the test organism is smeared on a filter paper piece, soaked with few drops of oxidase reagent. If the organisms are oxidase producing, the phenylenediamine in the reagent is oxidized to a deep purple color.
Requirements:-
Oxidase reagent: 1.0 g/dl tetramethyl p- phenylenediamine dihydrochoride in distilled water (it should be prepared fresh if it appears blue in color.)
2 filter paper strips
v Procedure:-
1. Place a piece of filter paper a clean petri dish.
2. Add 2 to 3 drop of freshly prepared oxidase reagent.
3. Smear a colony of the organism on the filter paper by using a
glass rod.
v Observation:-
1. Blue purple color : positive test
2. No blue purple color : negative
test
v Quality control:-
Use following microorganisms to confirm the reliability of reagents:
Positive control: Pseudomonas aeruginosa
Negative control: E. coli
