Aerobes, facultative anaerobes, and microaerophiles may produce hydrogen peroxide and/or superoxide as a result of aerobic respiration (oxygen is final electron acceptor). These organisms must be able to break down hydrogen peroxide (and/or superoxide) via production of: catalase enzyme degrades hydrogen peroxide into water and free oxygen gas; superoxide dismutase enzyme degrades superoxide into hydrogen peroxide.
A trypticase soy agar (TSA) broth/slant/dish is inoculated and incubated. Add 3-4 drops of hydrogen peroxide and observe for bubble formation (positive test result for catalase).
Clinical significance. The catalase test helps to differentiate between Staphylococci (catalase positive), Streptococci (catalase negative), and members of Enterobacteriaceae.
Reference
Cappuccino, J. G., & Welsh, C. (2018). Microbiology: A laboratory manual.
