| Technique | OXIDASE ,(/,)/,( |
| Principle | The enzyme indophenol oxidase which is produced by many microbes will turn phenylenediamine reagent (tetramethyl-para-phenylenediamine) black. When phenylenediamine reagent is poured onto a a plate containing suspected colonies, those colonies that produce oxidase will rapidly turn black. Oxidase test disks are filter disks impregnated with phenylenediamine reagent. . |
| Cautions | Nichrome wire, which is commonly
used for loops and stabs, will catalyze the reaction non
enzymatically and colonies should be picked with a
platinum wire or with a wooden toothpick The reagent can blacken spontaneously within 2-3 minutes. |
| Method | Individual colonies can be picked and smeared onto an oxidase test disk.. |
| Results | A test will be positive is the phenylenediamine reagent turns black within 10 seconds |
| Positive control | Pseudomonas and Neisseria |
| Negative control | |
| Reagents | |
| Reference |