Ultrastructure of Calymmatobacterium granulomatis in Lesions of granuloma inguinale.

Biopsy specimens from the lesions of 14 patients with granuloma inguinale were examined by electron microscopy. Calymmatobacterium granulomatis, the presumed causative agent, was observed within the phagosomes of many macrophages, but only rarely in polymorphonuclear leukocytes. The morphology of the organisms was that of a gram-negative bacteria having a large capsule and no flagella. These morphologic observations are consistent with published findings suggesting that this organism is related antigenically to organisms of the genus Klebsiella.