Which Legionella species is positive for hippurate hydrolysis?

Which Legionella species is positive for hippurate hydrolysis?

• A. L. micdadei
• B. L. pneumophila
• C. L. longbeachae
• D. L. gormanii

Answer: (B)

Hippurate hydrolysis tests for the presence of hippuricase, an enzyme that cleaves hippurate into glycine and benzoic acid. The detection reaction typically yields a color change when glycine is produced, so a positive result indicates hippurate breakdown. Among Legionella species, L. pneumophila uniquely shows hippurate hydrolysis under standard testing conditions, so a positive result points to this species. The other Legionella listed—L. micdadei, L. longbeachae, and L. gormanii—are generally hippurate negative, meaning they do not hydrolyze hippurate in the same assay. So, a positive hippurate hydrolysis result helps identify L. pneumophila in this context.

Hippurate hydrolysis tests for the presence of hippuricase, an enzyme that cleaves hippurate into glycine and benzoic acid. The detection reaction typically yields a color change when glycine is produced, so a positive result indicates hippurate breakdown.

Among Legionella species, L. pneumophila uniquely shows hippurate hydrolysis under standard testing conditions, so a positive result points to this species. The other Legionella listed—L. micdadei, L. longbeachae, and L. gormanii—are generally hippurate negative, meaning they do not hydrolyze hippurate in the same assay.

So, a positive hippurate hydrolysis result helps identify L. pneumophila in this context.