Species belonging to the filamentous fungal genus Trichoderma are well known as potential candidates for biological control of plant pathogenic fungi and as cellulase producers of biotechnological importance. However, several data were published in the last decade about the clinical importance of this genus indicating, that Trichoderma strains may be potential opportunistic pathogens of immunocompromised patients. Six species of the genus Trichoderma (T. citrinoviride, T. harzianum, T. koningii, T. longibrachiatum, T. pseudokoningii and T. viride) have been identified up to now as etiologic agents of infections in immunocompromised hosts.

The aims of our project are to gain information about both the biochemical and genetical properties of Trichoderma strains isolated either from natural environment or from clinical samples, to detect variability among the strains, and to determine properties helping the differentiation between facultative pathogenic and non-pathogenic strains within certain species aggregates. We are performing experiments to investigate the strains concerning their ecophysiological properties, carbon source utilization capabilities, their susceptibility to antifungal agents and their abilities to produce extracellular enzymes with possible roles in facultative pathogenesis. We plan to examine the size of the mitochondrial genome, the DNA-polymorphism, and the inter- and intraspecific variability of nuclear and mitochondrial DNA in the case of clinical and saprophytic Trichoderma isolates belonging to the same species aggregates. Further examinations will be carried out to look for the presence of extrachromosomal genetic elements among the examined strains.

We will try to find correlation between molecular markers and pathogenicity properties of the strains, which could help the clinical practice in the establishment of strain typing procedures.