Random amplification of polymorphic DNA (RAPD) fingerprinting and species delineation of filamentous fungi

Early diagnosis and identification of specific etiologic agents of invasive fungal infections is important for the appropriate and effective antifungal treatment regimen. Standard culture techniques have a low yield and frequently take long periods of time. In addition, species and strain variations are important for epidemiological studies. We present a method of identifying various species of filamentous fungi using RAPD which provides discrimination between different fungal species. 20 clinical isolates of aspergillus and 8 other fungi were evaluated. DNA was amplified using 6 different 10-mer primers and the products analyzed. We are able to easily differentiate between A. fumigatus (Afu) and A. flavus (Afl), and between the various other fungi. In addition, these primers enable us to delineate strain-to-strain variations within a species. We have also identified PCR products that specifically hybridize to Afu and Afl. These primers were derived from sequences for species-specific identification of these fungi from affected tissues. In conclusion, RAPD identification and fingerprinting of Aspergillus spp. and other medically relevant filamentous fungi is easily reproducible and less labor intensive than other methods. These procedures may eventually be suited for direct analysis of clinical material.