Description

INTENDED USE

Catalase Reagent is used to detect the presence of the enzymes, catalase and peroxidase, produced by some bacteria. Catalase Reagents are useful in the presumptive identification and differentiation of many bacteria. Beta-hemolytic organisms, such as Streptococcus species (catalase-negative), Staphylococcus species (catalase-positive), and Listeria species (catalase-positive) can be differentiated by their catalase reaction using 3% hydrogen peroxide. For catalase testing of anaerobic bacteria, 15% hydrogen peroxide appears to be more sensitive than 3% hydrogen peroxide.

SUMMARY AND EXPLANATION

Most cytochrome containing organisms produce a catalase enzyme which breaks down hydrogen peroxide into oxygen and water. When a small amount of a catalase producing organism is introduced into hydrogen peroxide, bubbles of oxygen form as a result of the enzyme’s activity.

PRINCIPLE

In the respiratory chain of all bacteria, reduced flavoproteins and iron-sulfur proteins unite with oxygen and oxidases to form two compounds, hydrogen peroxide and the superoxide radical. These compounds, if allowed to accumulate, are toxic to bacteria and results in their death. Bacterial survival is accomplished by the production of specific enzymes that allow bacteria to neutralize the toxic compound.

Hydrogen peroxide is decomposed by the action of two enzymes: catalase and either a peroxidase, NADH, NADPH, cytochrome c, or glutathione. To observe the action of these enzymes, catalase reagent, a dilute solution of hydrogen peroxide, is added to a pure bacterial culture. Any immediate bubbling is indicative of a positive result since oxygen is a byproduct of hydrogen peroxide decomposition.