12.6.4: Oxidase Test

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Note

Videos review: Performing an Oxidase Test: Gibson Oxidase Swab Method

In this lab a Gibson Oxidase Swab is used to perform the oxidase test. The oxidase test is based on the bacterial production of an oxidase enzyme. Cytochrome oxidase, in the presence of oxygen, oxidizes the N-N-N-tetra-methyl-p-phenylenediamine oxidase test reagent in a Gibson oxidase swab.

To perform the oxidase test, touch the oxidase test swab to a colony on a culture medium. An oxidase-positive reaction will appear purple to black within 10 seconds (see Fig. \(\PageIndex{1A\)) . An oxidase-negative test will result in no color change (see Fig. \(\PageIndex{1B\)). Ignore any color development occurring after 60 seconds.

Fig. \(\PageIndex{1A)\): A Positive Oxidase Test	Fig. \(\PageIndex{1B)\): A Negative Oxidase Test

Touch the Gibson Oxidase Test swab to a colony. An oxidase-positive reactions will appear purple to black within 10 seconds as shown in the above image. Disregard any color development that appears after 60 seconds.	Touch the Gibson Oxidase Test swab to a colony. An oxidase-positive reactions will appear purple to black within 10 seconds as shown in the above image. No change in color is negative. Disregard any color development that appears after 60 seconds.
Copyright; Gary E. Kaiser, Ph.D. The Community College of Baltimore County, Catonsville Campus CC-BY-3.0

Pseudomonas aeruginosa and most other glucose non-fermenting, Gram-negative bacilli are oxidase-positive. Except for the genus Plesiomonas, the glucose fermenting Enterobacteriaceae are oxidase-negative.

Contributors and Attributions

Dr. Gary Kaiser (COMMUNITY COLLEGE OF BALTIMORE COUNTY, CATONSVILLE CAMPUS)