Decline of Mycobacterium leprae in skin during and after treatment

Representative portions of sequential, annual biopsies of skin lesions from one lepromatous patient are shown, starting with the initial, pretreatment biopsy (t = 0). The patient was treated with the National Hansen's Disease Program recommended multidrug treatment (MDT) regimen of daily rifampin, dapsone, and clofazimine. Bacterial morphology had changed at one year; organisms are numerous but show evidence of degeneration. Treatment was discontinued at the time of the biopsy taken at two years. The bacterial load continued to decline slowly after MDT was discontinued, but rare organisms could still be observed after six years. Clinically, the cutaneous lesions resolved and did not relapse. (Fite stains, all at 1000x magnification.)