Identifying the emerging human pathogen Scedosporium prolificans by using a species‐specific monoclonal antibody that binds to the melanin biosynthetic enzyme tetrahydroxynaphthalene reductase. (7th May 2014)

• Record Type: Journal Article
• Authors: Thornton, Christopher R.; Ryder, Lauren S.; Le Cocq, Kate; Soanes, Darren M.
• Is Part Of: Environmental microbiology. Volume 17:Number 4(2015:Apr.)
• Page Start: 1023
• Page End: 1038
• Publication Date: 2014-05-07
• Subjects: Microbial ecology -- Periodicals; Environmental Microbiology -- Periodicals; 579.17
• DOI: 10.1111/1462-2920.12470
• Languages: English
• ISSNs: 1462-2912

Abstract

<abstract abstract-type="main"> <title>Summary</title> <p>The dematiaceous (melanized) fungus <italic>S</italic><italic>cedosporium prolificans</italic> is an emerging and frequently fatal pathogen of immunocompromised humans and which, along with the closely related fungi <italic>P</italic><italic>seudallescheria boydii</italic>, <italic>S</italic><italic>cedosporium apiospermum</italic> and <italic>S</italic><italic>. aurantiacum</italic> in the <italic>P</italic><italic>seudallescheria</italic>–<italic>S</italic><italic>cedosporium</italic> complex, is a contributing aetiology to tsunami lung and central nervous system infections in near‐drowning victims who have aspirated water laden with spores. At present, the natural habitat of the fungus is largely unknown, and accurate detection methods are needed to identify environmental reservoirs of infectious propagules. In this study, we report the development of a monoclonal antibody (mAb) (CA4) specific to <italic>S</italic><italic>. prolificans</italic>, which does not cross‐react with closely related fungi in the <italic>P</italic><italic>seudallescheria</italic>–<italic>S</italic><italic>cedosporium</italic> complex or with a wide range of mould and yeast species pathogenic to humans. Using genome sequencing of a soil isolate and targeted gene disruption of the CA4 antigen‐encoding gene, we show that mAb CA4 binds to the melanin‐biosynthetic enzyme tetrahydroxynaphthalene reductase. Enzyme‐deficient mutants produce orange‐brown or green‐brown spore suspensions compared with the black spore suspension of the wild‐type strain. Using mAb CA4 and a mAb (HG12) specific to the related fungi <italic>P</italic><italic>. boydii</italic>, <italic>P</italic><italic>. apiosperma</italic>, <italic>S</italic><italic>. apiospermum</italic> and <italic>S</italic><italic>. aurantiacum</italic>, we demonstrate how the mAbs can be used in combination with a semiselective isolation procedure to track these opportunistic pathogens in environmental samples containing mixed populations of human pathogenic fungi. Specificity of mAb CA4 was confirmed by sequencing of the internally transcribed spacer 1 (ITS1)‐5.8S‐ITS2 rRNA‐encoding regions of fungi isolated from estuarine muds.</p> </abstract>