Campylobacter jejuni is characterized by which attribute?

• A. Hippurate hydrolysis positive
• B. Nonmotile
• C. Oxidase negative
• D. A straight gram-negative bacillus

Answer: (A)

Hippurate hydrolysis positivity is a distinguishing biochemical trait of Campylobacter jejuni. This organism produces hippuricase, which cleaves hippurate into glycine and benzoic acid; in the laboratory, glycine reacts with a reagent to give a color change, indicating a positive hippurate test. This result helps separate C. jejuni from closely related species such as C. coli, which are hippurate negative. Other statements don’t fit: Campylobacter jejuni is motile with a polar flagellum (not nonmotile), it is oxidase positive (not negative), and it appears as a curved, not straight, gram-negative bacillus. So the positive hippurate hydrolysis result best identifies C. jejuni.