AUTHOR=Harun Azian , Kan Alex , Schwabenbauer Katharina , Gilgado Felix , Perdomo Haybrig , Firacative Carolina , Losert Heidemarie , Abdullah Sarimah , Giraud Sandrine , Kaltseis Josef , Fraser Mark , Buzina Walter , Lackner Michaela , Blyth Christopher C. , Arthur Ian , Rainer Johannes , Lira José F. Cano , Artigas Josep Guarro , Tintelnot Kathrin , Slavin Monica A. , Heath Christopher H. , Bouchara Jean-Philippe , Chen Sharon C. A. , Meyer Wieland 

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

JOURNAL=Frontiers in Cellular and Infection Microbiology

VOLUME=11

YEAR=2021

URL=https://www.frontiersin.org/journals/cellular-and-infection-microbiology/articles/10.3389/fcimb.2021.761596

DOI=10.3389/fcimb.2021.761596

ISSN=2235-2988

ABSTRACT=<p><italic>Scedosporium</italic> spp. are the second most prevalent filamentous fungi after <italic>Aspergillus</italic> 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, <italic>Scedosporium aurantiacum</italic> has emerged as an important fungal pathogen in a range of clinical settings. To investigate the population genetic structure of <italic>S. aurantiacum</italic>, 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 <italic>S. aurantiacum</italic> MLST scheme: actin (<italic>ACT</italic>), calmodulin (<italic>CAL</italic>), elongation factor-1α (<italic>EF1</italic>α), RNA polymerase subunit II (<italic>RPB2</italic>), manganese superoxide dismutase (<italic>SOD2</italic>), and β-tubulin (<italic>TUB</italic>). 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 <italic>S. aurantiacum</italic> 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 <uri xlink:href="http://mlst.mycologylab.org" xmlns:xlink="http://www.w3.org/1999/xlink">http://mlst.mycologylab.org</uri>. This is a joined publication of the ISHAM/ECMM working groups on “<italic>Scedosporium/Pseudallescheria</italic> Infections” and “Fungal Respiratory Infections in Cystic Fibrosis”.</p>