BACILLUS-PILIFORMIS INFECTION (TYZZERS DISEASE) IN A PATIENT INFECTEDWITH HIV-1 - CONFIRMATION WITH 16S RIBOSOMAL-RNA SEQUENCE-ANALYSIS

Bacillus piliformis is a long, rod-shaped bacterium that has never bee n grown in cell-free medium and whose taxonomic classification is unce rtain. B. piliformis is the causative agent of Tyzzer's disease, which is frequently reported in laboratory, wild, and domesticated animals. The spectrum and severity of this disease is wide in animals. Althoug h many infections are rapidly fatal, subclinical infections are also c ommon. To date, there have been no reports of B. piliformis infection in human beings, although elevated antibody levels have been reported in pregnant women. We describe the first case of human B. piliformis i nfection, in a man with HTV-1 infection and chronic, localized, cruste d verrucous lesions. The diagnosis was confirmed by ribosomal RNA sequ encing. The spectrum of organisms leading to infection and the spectru m of diseases caused by these organisms continue to expand, as new inf ections are identified and as patients with HTV-1 live longer with mor e severe immune suppression. The extreme difficulty in culturing B. pi liformis and the lack of clinical and histopathologic experience with this organism in human beings mean that B. piliformis is potentially a nother infectious agent to be considered in human beings. Also, when a n infectious organism is a strong clinical consideration, silver stain s may be of use when results of routine bacterial staining are negativ e.