What biochemical test is primarily used to determine the urease production of bacteria?

The biochemical test used to determine urease production in bacteria is the urease test. This test specifically measures the ability of an organism to produce the enzyme urease, which hydrolyzes urea into ammonia and carbon dioxide. The production of ammonia increases the pH of the environment, leading to a color change in the test medium, typically from yellow to pink due to pH indicator phenol red in the medium.

This characteristic is significant in identifying particular species of bacteria, especially urease-positive organisms such as Helicobacter pylori and certain species of Proteus. The other tests mentioned do not specifically assess urease production:

• The Simmon's Citrate test evaluates the ability of an organism to utilize citrate as its sole carbon source.
• The methyl red test assesses the production of stable acids from glucose fermentation, reflecting the metabolic pathway used by the organism.
• The oxidase test detects the presence of cytochrome c oxidase enzyme involved in electron transport in aerobic respiration.

Thus, the urease test is distinct in its purpose and results related to urease enzyme activity.