Pseudallescheria boydii infection of the bloodstream system: First reported case from China

Pseudallescheria boydii (P. boydii) is widely found in soil, sewage, decaying organic matter, and feces. Although it is associated with various clinical infections, no bloodstream infection has been reported. A 61-year-old male patient diagnosed with squamous cell carcinoma who is currently undergoing chemotherapy. The patient underwent blood culture sampling due to fever. Microscopic examination, SDA plate morphology, and mass spectrometry analysis confirmed the pathogen as P. boydii, which was further confirmed by internal transcribed spacer DNA sequencing. During treatment, empirical treatment voriconazole was significantly more effective than micafungin in treating P. boydii infection. In vitro antifungal susceptibility testing of the fungal isolates showed a very low MIC for voriconazole. In conclusion, bloodstream infections of P. boydii can occur in immunocompromised patients, and routine mass spectrometry techniques can assist in its rapid and accurate diagnosis. Additionally, empirical antifungal therapy with voriconazole remains effective in treating bloodstream infections caused by P. boydii.