Molecular Identification of Melanised Non-Sporulating Moulds: A Useful Tool for Studying the Epidemiology of Phaeohyphomycosis
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Subcutaneous infections caused by melanised fungi have been increasingly reported among transplant patients, and these infections have the potential for blood and visceral dissemination. Some moulds, such as Mycelia sterilia, cannot grow and sporulate on different media, making their identification impossible by conventional methods. The fast and accurate identification of melanised fungi at the species level is important because species may have tropism to different organs and different susceptibilities to antifungal agents. Molecular tools have been reported to be helpful for the species identification of non-sporulating moulds. Our goal was to identify the species of M. sterilia isolates obtained from clinical samples of transplant patients using sequences of ITS and the D1/D2 regions of rDNA. Clinical samples were obtained from eight kidney transplant recipients who developed subcutaneous fungal infections. The diagnosis was confirmed by histopathology and conventional culture. Histopathology showed septated, melanised hyphae, and the cultures identified non-sporulating fungi. Therefore, the DNA from the M. sterilia isolates was subjected to PCR amplification and sequencing of the ITS and D1/D2 regions. Genus/species identification was obtained by comparison with gene banks. We obtained the following identifications: Alternaria sp. (2), Cochliobolus lunatus/Curvularia lunata (2), Cochliobolus hawaiiensis/Bipolaris hawaiiensis (1), Ochroconis sp. (1), Medicocopsis romeroi/Pyrenochaeta romeroi (1) and Nigrograna mackinnonii/Pyrenochaeta mackinnonii (1).
KeywordsNon-sporulating moulds Melanised fungi Transplant patient Mycelia sterilia
We are in debt with Professor Dr. José Osmar Medina-Pestana, Head of Kidney and Hypertension Hospital (UNIFESP). We are also grateful to the Infectious Diseases and Dermatology teams that are responsible for the clinical support to transplant recipients. This project was approved by the Ethical Committee of the UNIFESP No. 0524/08. The authors report no conflicts of interest and are responsible for the content and writing of this paper.
- 6.Robert T, Talarmin JP, Leterrier M, Cassagnau E, Pape PL, Danner-Boucher I, Malard O, Brocard A, Gay-Andrieu F, Miegeville M, Morio F. Phaeohyphomycosis due to Alternaria infectoria: a single-center experience with utility of PCR for diagnosis and species identification. Med Mycol. 2012;50(6):594–600.PubMedCrossRefGoogle Scholar
- 9.Bagyalakshmi R, Therese KL, Prasanna S, Madhavan HN. Newer emerging pathogens of ocular non-sporulating molds (NSM) identified by polymerase chain reaction (PCR)-based DNA sequencing technique targeting internal transcribed spacer (ITS) region. Curr Eye Res. 2008;33(2):139–47.PubMedCrossRefGoogle Scholar
- 10.Gerrits van den Ende AHG, de Hoog GS. Variability and molecular diagnostics of the neurotropic species Cladophialophora bantiana. Stud Mycol. 1999;43:152–62.Google Scholar
- 13.Samson RA, Hoekstra ES, Frisvad JC. Introduction to food and airborne fungi. 7th ed. Utrecht: Centraalbureau voor Schimmelcultures; 2004.Google Scholar
- 15.White TJ, Bruns T, Lee S, Taylor J. Amplification and direct sequencing of fungal ribosomal RNA genes for phylogenetics. In: Innis A, Gelfand DH, Sninsky JJ, White TJ, editors. PCR protocols: a guide to methods and applications. San Diego, CA: Academic Press; 1990. p. 315–22.Google Scholar
- 25.Dupont C, Duong T, Mallet S, Mamzer-Bruneel M, Thervet E, Bougnoux M, et al. Unusual presentation of chromoblastomycosis due to Cladophialophora carrionii in a renal and pancreas transplant recipient patient successfully treated with posaconazole and surgical excision. Transpl Infect Dis. 2010;12:180–3.PubMedCrossRefGoogle Scholar
- 30.De Gruyter J, Woudenberg JHC, Aveskamp MM, Verkley GJM, Groenewald JZ, Crous PW. Rediposition of Phoma-like anamorphs in Pleosporales. Stud Mycol. 2012;75:1–36.Google Scholar
- 37.Martin-Sanchez PM, Nováková A, Bastian F, Alabouvette C, Saiz-Jimenez C. Two new species of the genus Ochroconis, O. lascauxensis and O. anomala isolated from black stains in Lascaux Cave, France. fungal. Biol. 2012;116(5):574–89.Google Scholar
- 45.Young NA, Kwon-Chung KJ, Greeman J. Subcutaneous abscess caused by Phoma sp. resembling Pyrenochaeta romeroi. Unique fungal infection occurring in immunosuppressed recipient of renal allograft. Amer J Clin Pathol. 1973;59:810–6.Google Scholar