Granuloma inguinale (donovanosis) is caused by which organism?

• A. Klebsiella granulomatis
• B. Haemophilus ducreyi
• C. Chlamydia trachomatis
• D. Treponema pallidum

Answer: (A)

Granuloma inguinale is caused by Klebsiella granulomatis, a gram-negative intracellular bacterium that lives inside macrophages and forms Donovan bodies visible on tissue smear. This infection produces painless, progressive beefy-red ulcers that bleed easily, a hallmark that helps distinguish it from other sexually transmitted ulcers. Haemophilus ducreyi causes chancroid, which presents as painful ulcers with tender inguinal nodes. Chlamydia trachomatis causes lymphogranuloma venereum, characterized by tender lymphadenopathy and systemic features. Treponema pallidum causes syphilis, which begins with a painless chancre and has distinctive serologic findings. The presence of Donovan bodies within macrophages points to Klebsiella granulomatis as the culprit.