What does a positive urease test indicate?

A positive urease test indicates that the bacterium can hydrolyze urea, which leads to the production of ammonia. This reaction increases the pH of the surrounding environment, often resulting in a color change in the test medium, typically from yellow to pink due to the alkaline conditions created by the ammonia. The urease enzyme breaks down urea, and the ability to produce urease is a key characteristic used to differentiate certain species of bacteria, especially in clinical microbiology, such as the identification of Helicobacter pylori and some members of the Enterobacteriaceae family.

The other options do not apply: the ability to hydrolyze urea directly correlates with urease activity, while aerobic characteristics, glucose fermentation, and hydrogen sulfide production pertain to different metabolic pathways and tests, thus not providing information pertinent to the urease test specifically.