Coelomycetous Fungi in the Clinical Setting: Morphological Convergence and Cryptic Diversity

Abstract

Human infections by coelomycetous fungi are becoming more frequent and range from superficial to systemic dissemination. Traumatic implantation of contaminated plant material is the most common cause. The typical morphological feature of these fungi is the production of asexual spores (conidia) within fruiting bodies called conidiomata. This study aimed to determine the distribution of the coelomycetes in clinical samples by a phenotypic and molecular study of a large set of isolates received from a U.S. reference mycological institution and by obtaining the in vitro antifungal susceptibility pattern of nine antifungals against a selected group of isolates. A total of 230 isolates were identified by sequencing the D1 and D2 domains of the large subunit (LSU) nuclear ribosomal RNA (nrRNA) gene and by morphological characterization. Eleven orders of the phylum Ascomycota were identified: Pleosporales (the largest group; 66.1%), Botryosphaeriales (19.57%), Glomerellales (4.35%), Diaporthales (3.48%), Xylariales (2.17%), Hysteriales and Valsariales (0.87%), and Capnodiales, Helotiales, Hypocreales and Magnaporthales (0.43% each). The most prevalent species were Neoscytalidium dimidiatum, Paraconiothyrium spp., Phoma herbarum, Didymella heteroderae, and Epicoccum sorghinum. The most common anatomical site of isolation was superficial tissue (66.5%), followed by the respiratory tract (17.4%). Most of the isolates tested were susceptible to the majority of antifungals, and only flucytosine showed poor antifungal activity.

Rapid and Robust Identification of the Agents of Black-Grain Mycetoma by Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry

“…This study utilized a mixture of historical eumycetoma agents and more recent isolates from imported cases of eumycetoma stored in NCPF, and the organisms utilized thus reflect those organisms encountered most frequently in the United Kingdom. While it does not cover the full spectrum of eumycetomal organisms, pleosporalean fungi were predominant among the eumycetomal organisms in our collection, in agreement with the findings of a variety of previous studies (12,13,21,26,33). Moreover, given the high log scores achieved with the organisms included here, coupled with the absence of an obvious overlap between spectral profiles (the next best matches were against unrelated organisms and had only very poor scores), we believe that the retrieval of reliable and unique MSPs should also be possible with mycetoma agents that are underrepresented or absent from the current study.…”

In vitro susceptibilities of Neoscytalidium spp. sequence types to antifungal agents and antimicrobial photodynamic treatment with phenothiazinium photosensitizers

“…[4,7,34]. Thus, results of the in vitro susceptibility testing with these fungi should be interpreted very carefully.…”

“…The taxonomy of the genera is still very problematic and has been constantly revised [2][3][4]. These fungal species are worldwide distributed in tropical and subtropical regions and are principally known as phytopathogens but some species can infect humans via direct contact with colonized plants [1].…”

Phaeohyphomycosis caused by Medicopsis romeroi in solid organ transplant recipients: Report of two cases and comprehensive review of the literature

“…Morphological identification of M romeroi, a coelomycetous fungus uncommonly isolated in Western countries, is difficult and requires mycological expertise. Clinical isolates often fail to produce characteristic structures such as pycnidia in culture media, and molecular techniques available in reference mycology laboratories (ie, sequencing only of specific fungal regions) may be needed to achieve reliable identification . The isolates from our clinical report and those of the literature review were all identified by molecular sequencing, highlighting the importance of these tests for identifying uncommon melanized fungi such as M romeroi .…”