Donovan bodies in a groin lymph node biopsy indicate infection with a pathogen that...

• A. Urethral swab should be collected
• B. Lymph node aspirate should be collected
• C. Blood culture should be ordered
• D. The causative agent cannot be cultured on routine laboratory media

Answer: (D)

Donovan bodies point to granuloma inguinale (donovanosis), caused by Klebsiella granulomatis. The organism is intracellular within macrophages and is notoriously difficult to culture on standard laboratory media; in fact, it cannot be cultured reliably on routine media. So, seeing Donovan bodies in a groin lymph node biopsy tells you the infecting agent is one that cannot be grown using ordinary culture methods, which is why diagnosis relies on histology or molecular detection rather than routine culture.