Which group of tests best differentiates Helicobacter pylori and C. jejuni?

The differentiation of Helicobacter pylori and Campylobacter jejuni can be effectively achieved through the use of urease, nitrate, and hippurate hydrolysis tests.

Helicobacter pylori is known for its ability to produce urease, an enzyme that hydrolyzes urea to ammonia and carbon dioxide, leading to an increase in pH. The presence of urease is a significant characteristic of H. pylori that aids in its identification.

Nitrate reduction is another distinguishing feature, as H. pylori can reduce nitrate to nitrite, whereas C. jejuni has different metabolic pathways that do not typically include nitrate reduction to the same extent.

Hippurate hydrolysis is particularly useful in differentiating these two organisms. Campylobacter jejuni can hydrolyze hippurate, which is not a characteristic of H. pylori. This test result is instrumental in identifying C. jejuni, making the combination of these tests particularly effective for differentiation.

In contrast, while catalase and oxidase tests can be useful for identifying both organisms, they do not provide the specificity needed to distinguish between them effectively. Additionally, nalidixic acid and cephalothin sensitivity tests are more related to antibiotic sensitivity rather than direct biochemical