MYCOLOGICAL LABORATORY COLLECTION
Fungi are ubiquitous organisms that mediate critical biological and ecological processes. They have significant roles as saprotrophs and symbionts in the breakdown and nutrient cycling of plant and animal remains, as parasites and in human, animal and plant diseases.
However, the biodiversity of fungi has been poorly documented. It has been estimated that there could be 1.5 million fungal species on earth based on the ratio of fungi to vascular plants. Only 5% of this estimate have been described. Many species of fungi have yet to be described and at the same time the knowledge of classical features (morphology and physiology of fungi) is declining.
Pathogenic yeasts and filamentous fungi are increasingly implicated as causes of life-threatening diseases in immunocompromised and/or debilitated hosts and are a major cost burden on the health system with 25.000 Euro/year for example in Australia alone. This is based on an average cost for fungal disease treatment of 31.000 Euro/year per patient, based on a conservative estimate of 600-800/patients/year [data obtained from Australian Mycological Interest Group].
Fungi now account for 10% of all hospital-acquired infections and are amongst the commonest AIDS-associated, opportunistic infections. More and more environmental fungi are causing diseases in humans with the increasing number of immunocompromised patients. Many emerging pathogens are inherently resistant to marketed antifungal drugs, and therapeutic responses of the common infections remain sub-optimal. Therefore, it is important to understand mechanisms of pathogenicity, including questions of: the occurrence of mutations during evolution and microevolution and/or lateral gene transfer; and to improve the speed and accuracy of fungal identification.
At present accurate speciation of fungi is the most useful predictor of therapeutic response. Current techniques for fungal identification are insensitive, not always specific, slow, labour-intensive and require skilled personnel to identify the less common pathogens. Molecular methods based on an accurate phylogenetic reference system offer a big advantage over conventional phenotypic methods because they are based on the more stable genotypic characteristics and do not rely on culture and operator interpretation. They are rapid and can be applied directly to tissue and body fluid samples and do not require prior isolation of the pathogen into pure culture.