Oxidase Test

Cytochrome oxidase – this test determines the presence of cytochrome oxidase enzymes.

Oxidase reagent

Tetramethyl-P-Phenylenediamine Dihydrochloride 1.0g

d-H₂O 100 mL

The use of an iron-containing metal inoculation loop can lead to a false- positive reaction. Use only plastic or platinum loops for this test.

1. Add an inoculum of pure 18 -24 hour old bacterial culture to the test strip impregnated with reagent.

RESULTS:

Positive: purple color within 5-10 seconds (reactions that occur after 10 seconds are negative).(Pseudomonas, Neisseria, Alcaligens, Aeromonas, Campylobacter, Vibrio, Brucella, Pasteurella, Moraxella, Helicobacter pylori, Legionella pneumophila, etc.)

Negative: no purple color.( Family Enterobacteriaceae )

Quality Control

Positive: Pseudomonas aerugenosa

Negative: Escherichia coli

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