Multilocus Sequence Typing Reveals Extensive Genetic Diversity of the Emerging Fungal Pathogen Scedosporium aurantiacum.

Scedosporium spp. are the second most prevalent filamentous fungi after Aspergillus spp. recovered from cystic fibrosis (CF) patients in various regions of the world. Although invasive infection is uncommon prior to lung transplantation, fungal colonization may be a risk factor for invasive disease with attendant high mortality post-transplantation. Abundant in the environment, Scedosporium aurantiacum has emerged as an important fungal pathogen in a range of clinical settings. To investigate the population genetic structure of S. aurantiacum, a MultiLocus Sequence Typing (MLST) scheme was developed, screening 24 genetic loci for polymorphisms on a tester strain set. The six most polymorphic loci were selected to form the S. aurantiacum MLST scheme: actin (ACT), calmodulin (CAL), elongation factor-1α (EF1α), RNA polymerase subunit II (RPB2), manganese superoxide dismutase (SOD2), and ß-tubulin (TUB). Among 188 global clinical, veterinary, and environmental strains, 5 to 18 variable sites per locus were revealed, resulting in 8 to 23 alleles per locus. MLST analysis observed a markedly high genetic diversity, reflected by 159 unique sequence types. Network analysis revealed a separation between Australian and non-Australian strains. Phylogenetic analysis showed two major clusters, indicating correlation with geographic origin. Linkage disequilibrium analysis revealed evidence of recombination. There was no clustering according to the source of the strains: clinical, veterinary, or environmental. The high diversity, especially amongst the Australian strains, suggests that S. aurantiacum may have originated within the Australian continent and was subsequently dispersed to other regions, as shown by the close phylogenetic relationships between some of the Australian sequence types and those found in other parts of the world. The MLST data are accessible at http://mlst.mycologylab.org. This is a joined publication of the ISHAM/ECMM working groups on "Scedosporium/Pseudallescheria Infections" and "Fungal Respiratory Infections in Cystic Fibrosis".

A point prevalence survey on hand hygiene, with a special focus on Candida species.

BACKGROUND: A 1-day point prevalence study evaluated hand hygiene compliance, yeast colonization, and contamination, focusing on the hands of health care workers (HCWs) and patient-oriented surfaces. METHODS: Hand hygiene compliance was evaluated by applying the direct observation technique and the World Health Organization's compliance program, "My Five Moments for Hand Hygiene." A total of 128 samples from HCWs working in intensive care (n = 11) and intermediate care (n = 2) units and 65 environmental samples from Innsbruck Medical University Hospital were investigated. RESULTS: Hand hygiene compliance was superior for nurses (83.5%) and moderate for medical doctors (45.2%). In general, fungal growth was unique; only 9 of 128 HCW samples and only 4 of 65 environmental samples yielded positive results. The genetic relatedness of yeasts from the same species was investigated by random amplified polymorphic DNA (RAPD) typing. RAPD profiles exhibited the potential for cross-transmission of yeasts. CONCLUSION: In general, the fungal colonization and contamination rate was low, but a high level of hand hygiene compliance was lacking.

Phylogeny and immune evasion: a putative correlation for cerebral Pseudallescheria/Scedosporium infections.

Representatives of the genus Pseudallescheria (anamorph: Scedosporium) are saprobes and the aetiologic agent of invasive mycosis in humans. After dissemination, the central nervous system (CNS) is one of the most affected organs. Prerequisites for the survival of Pseudallescheria/Scedosporium in the host are the ability to acquire nutrients and to evade the immune attack. The cleavage of complement compounds via the secretion of fungal proteases might meet both challenges since proteolytic degradation of proteins can provide nutrients and destroy the complement factors, a fast and effective immune weapon in the CNS. Therefore, we studied the capacity of different Pseudallescheria/Scedosporium species to degrade key elements of the complement cascade in the cerebrospinal fluid and investigated a correlation with the phylogenetic background. The majority of the Pseudallescheria apiosperma isolates tested were demonstrated to efficiently eliminate proteins like complement factors C3 and C1q, thus affecting two main components of a functional complement cascade, presumably by proteolytic degradation, and using them as nutrient source. In contrast, the tested strains of Pseudallescheria boydii have no or only weak capacity to eliminate these complement proteins. We hypothesise that the ability of Pseudallescheria/Scedosporium strains to acquire nutrients and to undermine the complement attack is at least partly phylogenetically determined.

Efficacy of a selective isolation procedure for members of the Pseudallescheria boydii complex.

Members of the P. boydii species complex (Microascaceae) are frequently involved in human opportunistic disease. Studies indicate that the prevalent habitat of P. boydii sensu lato is in agriculturally exploited or otherwise human-impacted soils. Quantitative analysis of fungal indicators in the environment can be exploited for monitoring of general environmental changes, as well as for understanding local population changes and its epidemiological consequences. In this study we present the development and testing of a semi-selective isolation procedure for P. boydii and related species. Three general media, DG18, rose bengal agar and five variations of modified Leonian's agar with and without benomyl were tested. Germination percentages of P. boydii, S. prolificans, Petriella spp. and Aspergillus fumigatus (control) were evaluated. Tests were carried out on the success of P. boydii isolation from inoculum mixed with A. fumigatus. Subsequently the procedure was applied to water, sediment and soil samples. On the newly introduced semi-selective medium (SceSel+), the germination of P. boydii was superior or similar to that seen on the other media tested. P. boydii was isolated from mixed cultures only on SceSel+ but not on SceSel without benomyl. Isolation from environmental sources with SceSel+ was successful, and human impacted soil was confirmed as the predominant habitat of P. boydii.