Which biochemical feature is indicative of a positive catalase test?

The positive catalase test is indicated by the formation of bubbles upon the application of hydrogen peroxide (H2O2). This reaction occurs because catalase is an enzyme that breaks down hydrogen peroxide into water and oxygen. The visible bubbles are a direct result of the oxygen gas being released during this breakdown.

The presence of catalase is a key characteristic that helps to differentiate between certain groups of bacteria, especially when distinguishing Staphylococci, which are catalase-positive, from Streptococci, which are typically catalase-negative. This test is particularly useful in microbiology for the identification of bacterial species based on their enzymatic activity.