Diagnosis of invasive mycoses in severely immunosuppressed patients.

In compromised patients, invasive mycoses are being observed at an increasing frequency and with a broadening spectrum of causative fungi. The rapid and definitive diagnosis of such opportunistic mycoses requires the synoptical consideration of predisposing clinical conditions, of culture isolates, and of the results of nonculture techniques. At present, the latter comprise the monitoring of specific antibodies and of fungal antigens, and the microscopical examination of suspected biopsies. The validity of the individual techniques (e.g., the monitoring of antibodies or antigens) varies with individual mycoses. Alternative methods for monitoring fungal metabolites or nucleic acids are still in the developmental stage. Particularly the amplification of DNA by the polymerase chain reaction (PCR) has a high diagnostic potential. However, at present, it is uncertain whether PCR allows the necessary distinction between colonization and truly invasive infection, and whether PCR can be simplified sufficiently to allow the continuous surveillance of high-risk patients.