Calymmatobacterium granulomatis

Calymmatobacterium granulomatis is a bacterial species that is the causative agent of the sexually transmitted infection known as granuloma inguinale or Donovanosis. This bacterium is a Gram-negative, non-motile, encapsulated rod-shaped organism. It was first identified by Charles Donovan in 1905.

History

Charles Donovan, an Irish physician, first identified Calymmatobacterium granulomatis in 1905. He discovered the bacteria while studying tissue samples from patients suffering from granuloma inguinale. The bacteria was initially named Donovan bodies after him.

Characteristics

Calymmatobacterium granulomatis is a Gram-negative bacterium, meaning it does not retain the violet crystal violet stain used in the Gram stain procedure. Instead, it takes up the red counterstain. The bacterium is rod-shaped and non-motile, and it is encapsulated, which helps it evade the host's immune response.

Pathogenesis

Calymmatobacterium granulomatis causes granuloma inguinale, a sexually transmitted infection that results in ulcerative lesions primarily in the inguinal region. The bacteria are transmitted through direct skin-to-skin contact during sexual activity. Once in the host, the bacteria invade the monocytes and macrophages, where they multiply and spread to other tissues.

Diagnosis and Treatment

Diagnosis of granuloma inguinale is typically made by identifying Donovan bodies in tissue samples. Treatment typically involves antibiotics such as doxycycline, erythromycin, or trimethoprim/sulfamethoxazole.

See Also

• Sexually transmitted infection
• Granuloma inguinale
• Charles Donovan