In order to survive, organisms must rely on defense mechanisms that allow them to repair or escape the oxidative damage of hydrogen peroxide (H2O2). Some bacteria produce the enzyme catalase, which facilitates cellular detoxification. Catalase neutralizes the bactericidal effects of hydrogen peroxide and its concentration in bacteria has been correlated with pathogenicity. The catalase test facilitates the detection of this enzyme in bacteria. It is essential for differentiating catalase-positive Micrococcaceae from catalase-negative Streptococcaceae. While it is primarily useful in differentiating between genera, it is also valuable in speciation of certain gram positives.
