Spiromastigoides asexualis: Phylogenetic Analysis and Evaluation as a Cause of False-Positive Blastomyces DNA Probe Test Results.

This is the first case of Spiromastigoides asexualis human infection, and it notably gave a false-positive Blastomyces DNA probe laboratory result. We further investigated other Spiromastigoides isolates as a cause of false-positive testing results, their phylogenetic relationship, and their susceptibility profiles to clinically available antifungal agents. Other S. asexualis isolates also resulted in positive Blastomyces DNA probe results, while Spiromastigoides species other than S. asexualis did not.