Enteric Rods: Oxidase test
Another major characteristic that helps differentiate the Chart 4
organisms from other Gram-negative rods is the oxidase test. The oxidase test is
a quick and simple 5 minute test done directly from a bacterial colony on a
blood agar plate. Some bacteria possess a cytochrome oxidase system that
facilitates the utilization of oxygen as a final hydrogen acceptor in reducing
molecular oxygen to hydrogen peroxide. The oxidase strips or swabs contain
various reagents which support a series of reactions that lead to a final
oxidase reaction and a purple color. Oxidase negative organisms cause little or
no color change.
The slide above shows an oxidase positive sample on the left and an oxidase
negative sample on the right.
ALL OF THE CHART 4 ENTERIC RODS ARE OXIDASE NEGATIVE.
