Translations available in Spanish. Catalase Test Resource Type: Visual: Video Publication Date: Prior to 1/1/2002 Figure 1 QT-362Kb Authors Neal Chamberlain Department of Microbiology/Immunology A.T. Still University of Health Sciences/KCOM Kirksville, Missouri 63501 USA Email: nchamberlain@atsu.edu The submission is a 3 s QuickTime movie file of the catalase test. Cultures of Staphylococcus aureus (organism on left) and Streptococcus pyogenes (organism on the right) were grown on blood agar plates for 16 h at 37 degrees Celsius. A colony from each blood agar plate was then placed on a glass slide. A drop of 3% hydrogen peroxide was place on both organisms. The catalase-producing organism will catalyze the breakdown of hydrogen peroxide (H2O2) to oxygen and water. Oxygen is released from the hydrogen peroxide in the form of bubbles. The catalase test is used to differentiate Staphylococcus sp. from Streptococcus sp. Staphylococcus sp. are positive for catalase production. Streptococcus sp. are negative for catalase production. The production of catalase appears to protect the bacteria when hydrogen peroxide is produced during bacterial metabolism and if the bacteria are phagocytized by white blood cells. This video may be used in a discussion of biochemical tests for identifying microorganisms. It can also serve to illustrate how most aerobic microbes neutralize the toxic hydrogen peroxide they produce during metabolism. The catalase reaction of known species of bacteria can be found in Bergey's Manual. Reference: 1. Murray, Patrick R. et al. 1998. Medical microbiology, 3rd ed., p. 180. Mosby, St. Louis, Mo.