Background: Diagnosis of Blastomyces dermatitidis (Bd) infection is often via culture or histology. Urine Bd antigen detection is limited by cross-reaction with other fungi. Detection of Bd antibodies has not been clinically useful in humans. Methods: Blood and urine were collected from 9 adult subjects previously diagnosed with Bd infection. Diagnosis had been confirmed by culture and histological examination. Bd antibodies were measured via enzyme immunoassay with immunodiffusion Bd and Histoplasma capsulatum (Hc) antigens as well as Bd and Hc culture supernatants. An antigen detection kit (MiraVista Diagnostics) was used to detect serum and urine Bd antigen. Urine samples were also analyzed after 10x concentration. Results: All had multilobar pneumonia (1) or extrapulmonary disease (8). 6 had completed therapy. 3 were still on therapy. All had clinical improvement. Bd antibodies were negative or indeterminate in all 9. 3 had detectable Hc antibodies. Antigen results considered positive if >1.0. Previously treated subjects. Discussion: Persistent Bd antigenuria is found in some subjects on antifungal therapy despite clinical improvement. The significance of this or of voriconazole use is unclear, but the role of immune suppression in Bd relapse, especially in renal transplantion, has been noted in Bd. In immunocompetent subjects, antigenuria resolves after adequate therapy. Serum antibodies to Bd were not detected in those infected in the past or in those more recently infected.
Full conference title:
Infectious Diseases Society of America, 44th Annual Meeting
- IDSA 44th