Fusospirochetal superinfection of pre-existing oral lesion in patients with acquired immunodeficiency syndrome.

Three patients with AIDS presented with nonbleeding, painful, fetid, oral ulcers overlaid with a grayish-black semiadherent membrane at the sites of a pre-existing lesion. These lesions persisted despite treatment directed toward the primary etiology (cytomegalovirus, Kaposi's sarcoma). Gram- and Giemsa-stained smears of teased membrane fragments revealed an impressive bacterial flora with fusiforms and Borrelia-type spirochetes. Prompt treatment with penicillin brought amelioration of symptoms and sloughing of the overlaying membrane.