Invasive Trichosporon beigelii infection in immunosuppressed rats.

Fulminant systemic mycoses were seen as complications in rats undergoing drug trials for the treatment of Pneumocystis carinii pneumonia. Rats were immunosuppressed with corticosteroids and by feeding with a low-protein diet. Homogenized pulmonary tissue from a rat with pneumocystosis was inoculated transtracheally. Secondary invasive mycosis was found in 56 of 59 rats examined. Trichosporon beigelii was identified as the causative agent in the majority of cases. After examining possible sources of infection, a Pneumocystis inoculum contaminated with fungi was found to be the obvious source. T. beigelii infections are becoming increasingly significant in immunocompromised human patients. The need for suitable and reproducible animal models is therefore also increasing. Observations described in this paper may help in the further development of such models.