Research

Our research in fungal systematics has been funded through the Natural Sciences and Engineering Research Council of Canada and the University of Alberta Small Faculties Fund Support for the Advancement Scholarship. More details

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New cases of fungi affecting humans and animals (2011)

Geosmithia argillacea in patients was reported from seven cases of invasive infection in patients with chronic granulomatous disease. The patients responded poorly to treatment and three died. This fungus has been confused previously with Paecilomyces variotii. In these cases, both cultural morphology and molecular data were used to identify the fungal isolates.  

Myceliophthora thermophila is a thermophilic mold commonly found in silage, wood chips or soil. There are rare reports of infection. A case of invasive infection mimicking aspergillosis was diagnosed in an immunocompromised patient in France. Repeated samples were positive in the galactomannan (GM) assay, a test useful in the diagnosis of Aspergillus infections. M. thermophila was isolated from the patient and shown to also produce a positive result in the GM assay. This cases demonstrates the importance of culture for correct diagnosis of infection.

Metarhizium anisopliae is a cosmopolitan insect pathogen rarely associated with human or animal disease. We described a case of severe pneumonia in an American alligator. M. anisopliae was isolated in culture and identified by ITS sequencing. An unusual presentation was the heavy sporulation of the fungus in lung tissue that allowed for presumptive identification of the fungus as Metarhizium. A second unusual finding was the production of calcium oxalate crystals in the lung. The crystals were also produced in culture by the fungus.

 
Image (L) showing alligator lung tissue stained with PAS showing conidia and hyphae (courtesy Dr. K.W. Conley); (R) showing Metarhizium anisopliae UAMH 11138 isolated from alligator lung.

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A new pathogen associated with dogs

Phialosimplex caninus, a new genus and species, was described for several isolates of fungi associated with infections in canines.  Sagenomella chlamydospora, previously reported as the cause of disseminated infection in a dog, was shown to be a related species. The genus Phialosimplex is another member of the ascomycete family Trichocomaceae which includes many opportunistic pathogens belonging to the genera Aspergillus, Penicillium and Paecilomyces.

 

 

 

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A new fungus causing fatal infection in chameleons

A fungus causing an outbreak of systemic infection in a group of veiled chameleons (Chamaeleo calyptratus) was described as a new genus Chamaeleomyces granulomatis using morphological and molecular data. The affected chameleons were housed in a zoo collection in Denmark. The disease was notable for the development of large granulomas in multiple organs and the presence of large yellowish while nodules that were grossly visible in the liver and other organs. Fungal isolates from the various tissues were initially suspected to represent Paecilomyces viridis, a species previously identified as the cause of a single outbreak of fatal mycosis in carpet chameleons. However, molecular ata revealed that the Danish isolates represented a new but related species and that both species were members of a new genus within the ascomycete family Clavicipitaceae, that includes many insect pathogens. It is likely that the chameleons acquired the infection by ingesting infected insects. Many entomopathogenic fungi infect insects by penetration through the cuticle, followed by growth within the hemolymph in the form of yeast-like cells. Similarly, members of the genus Chamaeleomyces grow in the infected tissues of chameleons in the form of yeast-like cells and fungal filaments. 

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Description of the yellow rot pathogen of the medicinal mushroom Ganoderma lucidum

With colleagues in Korea, we identified a pathogen of cultivated Ganoderma lucidum. Ganoderma lucidum is a mushroom widely known for its medicinal properties and it is consumed as health food in Asia where it is known as Yeongii in Korea, Lingzhi in China, and Reishi in Japan. The mushroom is widely cultivated on oak logs in greenhouses. In Korea a fungal disease called yellow rot resulted in destructive lesions on the mushrooms and the causal agent became known as the yellow rot pathogen (YRP), but the identity of the fungus was uncertain. By means of morphological features, pathogenicity tests and phylogenetic analyses of DNA sequences, we found that the YRP isolates grouped with an ascomycete Xylogone sphaerospora and with a hyphomycete, Arthrographis cuboidea, but was distinct from either species. Scytalidium lignicola, the type species of Scytalidium, was also related but more distantly. We described the YRP pathogen as the new species Xylogone ganodermophthora and showed by pathogenicity tests that only this species was capable of causing symptoms in Ganoderma lucidum. Read more about G. lucidum

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Plant pathogens causing human infection

Macrophomina phaseolina, a plant pathogen, was reported for the first time as the cause of disseminated infection in a Canadian man, originally from Sri Lanka, who received a renal transplant in India. The patient subsequently succumbed to invasive infection with a different but related fungus, Neoscytalidium dimidiatum (formerly Scytalidium dimidiatum). Molecular data confirmed the identification of both fungi and revealed that they are related species within the ascomycete family Botryosphaeriaceae.

Mycoleptodiscus indicus, a fungus found in tropical or sub-tropical regions, caused septic arthritis of the knee in an otherwise healthy Canadian male. The fungal infection was diagnosed in Canada but thought to have been contracted while the patient vacationed in Costa Rica, probably through direct inoculation through injured skin. The fungus was isolated from synovial fluid and identification was confirmed by DNA sequencing.  

Another case of Mycoleptodiscus to be published in 2012 involves an immunocompromised patient who experienced necrotizing cellulitis and mycositis in the leg.

 

 

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A soil fungus causing fungemia in an immunocompromised host

 

Graphium basitruncatum, a fungus known previously from soil in Solomon Is. and Japan, was reported as the cause of fungemia in an immunocompromised patient from Canada. The fungus was isolated repeatedly from blood cultures and it spread to the skin, resulting in necrotic skin ulcers.

UAMH 10611 = GenBank EF165016

 

 

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Human nail pathogens in the genus Arachnomyces (Onychocola)

The nail pathogen, Arachnomyces kanei, was described for isolates obtained from abnormal nails of patients in a large Canadian study. Molecular analysis reveals that nail-associated fungi placed in the genus Arachnomyces belong to a new lineage of the ascomycetes (Arachnomycetaceae, Arachnomycetales). Onychocola canadensis, first described by us in 1990, is now recorded worldwide as an uncommon cause of nail disease. The infection occurs primarily in older individuals and often affects the big toenail. Infections are not easily cured. O. canadensis was the first species shown to have a sexual stage in the genus Arachnomyces. >>more

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Adiaspiromycosis caused by Emmonsia species

Emmonsia species are soil fungi that occasionally cause adiaspiromycosis, a pulmonary disease primarily of small rodents and other

burrowing animals. The tissue spore form consists of a large, globose, thick-walled, non-proliferating structure called an adia­spore. Human infections are rare, usually presenting as a diffuse pulmonary infection, and often diagnosed from histopathology. Comprehensive treatments of the fungi and infections are found in book chapters (e.g. Topley & Wilson's Microbiology and Microbial Infections 9th & 10th Ed). Information from mating and molecular phylogenetic studies confirm that Emmonsia species and Blastomyces dermatitidis are closely related and that these fungi, together with Paracoccidioides brasiliensis and Histoplasma species, belong to the Ajellomycetaceae. >>more

 

 

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A fungus causing disease in reptiles

The Chrysosporium anamorph of Nannizziopsis vriesii has been shown to naturally and experimentally cause severe and often fatal dermatitis in multiple reptile species including chameleons, snakes, and crocodiles. This fungus is suspected to be the cause of an emerging condition in captive bearded dragons that has been called “yellow fungus disease.”  >>more

 

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Two new species of fungi from shed skins of captive reptiles

Chlamydosauromyces punctatus, a new ascomycete and Acremonium exuviarum, a hyphomycete, were isolated from skin of a frilled lizard (Chlamydosaurus kingii) and Solomon Island skink (Corucia zebrata), respectively. Only a single isolate of each species is known.

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Plant root associated fungi

Members of the genus Cryptosporiopsis are increasingly being recognized as common endophytes in the roots of woody plants including aspen. Isolates from roots of ericaceous plants including Vaccinium species and Gaultheria shallon (salal) were described as new species, Cryptosporiopsis ericae and C. brunnea, based on morphological features and analysis of DNA sequences. Although both species have been obtained only from surface-sterilized roots of ericaceous plants, little is known about their role in roots.
>> read more on fungi from plant roots

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