Utility of anti-bacillus Calmette-Guérin antibodies as a screen for organisms in sporotrichoid infections.

Background: Sporotrichoid infections often present a diagnostic challenge for the dermatopathologist. Therefore an affordable, reliable method of easier recognition of organisms is desired. Recently, immunohistochemical staining with antibodies against Mycobacterium bovis (bacillus Calmette-Guérin, BCG) was found to be useful in identifying various fungi and mycobacteria with minimal background staining. Objective: The purpose of this study was to demonstrate the usefulness of anti-BCG antibodies as a screen for organisms in sporotrichoid infections. Methods: Thirteen specimens of suspected sporotrichosis were selected for staining with anti-BCG antibody. Sporotrichoid infection was confirmed by histochemical staining, biopsy, and follow-up results. Results: Twelve of the 13 specimens stained positively using anti-BCG antibody. Of the 5 cultures done, 2 were positive for M marinum, and 1 grew Sporothrix schenckii. Conclusion: Immunohistochemical staining with anti-BCG antibody offers another screening method to identify organisms in sporotrichoid infections because of its ease, cost-effectiveness, and simplicity. (J Am Acad Dermatol 2001;44:261-4.)