Sydney Medical School - Westmead Hospital - University of Sydney
Prof. Dr. rer. nat. Wieland Meyer
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.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.
The Molecular Mycology Research Laboratory at the Centre for Infectious Diseases and Microbiology, Marie Bashir Institute for Emerging Infectious Diseases and Biosecurity, Sydney Medical School - Westmead Hospital, Westmead Millennium Institute for Medical Research at the University of Sydney under the leadership of Professor Wieland Meyer
focuses on three major research fields:
1. Phylogeny, evolution and molecular identification of human and animal pathogenic fungi
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.
Our research is directed towards the selection of short species-specific genetic signatures to serve as DNA barcodes for molecular based fungal identification. As such, we lead a global collaborative effort to establish a quality ITS reference sequence database for human and animal pathogenic fungi, and develop species specific identification methods reaching from RFLP, over PCR-fingerprinting, rolling circle/LOOP PCR to MALDI-TOF.
2. Molecular epidemiology and investigation outbreaks/nosocomial infections due to human and animal pathogenic fungi, especially the members of the
To enable a better and faster response to fungal disease outbreaks or nosocomial infections the understanding of the population genetics and spread of d fungal disease agent is necessary. Our group was the first to develop DNA- and PCR-fingerprinting for fungal strain typing, and wend than on to establish Multilocus Microsatellite Typing and Multilocus Sequence typing for the human pathogenic fungi
, and are now applying whole genome sequencing to fungal epidemiology.
3. Molecular studies underlying the pathogenicity of
Many emerging pathogens are inherently resistant to marketed antifungal drugs, and therapeutic responses of the common infections remain sub-optimal. In addition there are substantial differences in pathogenicity/virulence between different strains within a fungal species. 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. To gain insides into these processes our group is applying comparative whole genome analysis followed by gene knockout and reconstitution experiments in conjunction with a number of animal models (mice and
Wieland Meyer Molecular Mycology Research Laboratory, Centre for Infectious Diseases and Microbiology, Sydney Medical School-Westmead Hospital, Marie Bashir Institute for Infectious Diseases and Biosecurity, University of Sydney, Westmead Millennium Institute, Sydney, Australia