First human case of pulmonary fungal ball due to a Perenniporia species (a basidiomycete)

Subcutaneous mycosis caused by filamentous basidiomycete Megasporoporia setulosa-first report of human infection

Filamentous basidiomycetes are an emerging cause of human infection in tropical and subtropical regions. We report a case of subcutaneous infection caused by the shelf fungus, Megasporoporia setulosa, in an immunocompetent male. This is also the first report of human infection caused by this filamentous basidiomycete. Identification of the fungus could only be achieved by sequencing the ITS and LSU regions of rDNA. The patient recovered following surgery and treatment with amphotericin B and oral itraconazole. This report underscores the cross-kingdom pathogenicity of plant fungi and the importance of molecular tools for definitive identification of nonsporulating fungal species.

Allergic Bronchopulmonary Mycosis Caused by Schizophyllum commune: A Special Interest in Positive Culture of Other Basidiomycetes Fungi

A 42-year-old man with asthma presented in 2007 with chest infiltration and productive cough. Pycnoporus sanguineus and Perenniporia tephropora were repeatedly isolated from sputum and bronchial washing fluids. Because we lacked immunologic evidence, we could not diagnose him with allergic bronchopulmonary mycosis (ABPM) due to these basidiomycetous fungi. At that time, serum-specific IgE and IgG against Schizophyllum commune findings were negative. Inhaled beclomethasone/salmeterol improved his condition. Seven years later, mucous plugs obtained via bronchoscopy at a relapse were compatible with allergic mucin. Because S. commune was isolated from mucous plugs and serum-specific IgG against S. commune turned positive, we diagnosed the patient with ABPM due to S. commune.

Determining the Pathogenic Potential of Non-sporulating Molds Isolated from Cutaneous Specimens

Although non-sporulating molds (NSM) are frequently isolated from patients and have been recognized as agents of pulmonary disease, their clinical significance in cutaneous specimens is relatively unknown. Therefore, this study aimed to identify NSM and to determine the keratinolytic activity of isolates from cutaneous sites. NSM isolates from clinical specimens such as skin, nail, and body fluids were identified based on their ribosomal DNA sequences. Of 17 NSM isolates (7 Ascomycota, 10 Basidiomycota), eleven were identified to species level while five were identified to the genus level. These include Schizophyllum commune, a known human pathogen, Phoma multirostrata, a plant pathogen, and Perenniporia tephropora, a saprophyte. To determine fungal pathogenicity, keratinolytic activity, a major virulence factor, was evaluated ex vivo using human nail samples by measuring dye release from keratin azure, for NSM along with pathogens (Trichophyton mentagrophytes, Trichophyton rubrum, Microsporum canis and Fusarium spp.) and nonpathogenic (endophyte) fungi for comparison. This study showed that pathogenic fungi had the highest keratinolytic activity (7.13 ± 0.552 keratinase units) while the nonpathogenic endophytes had the lowest activity (2.37 ± 0.262 keratinase units). Keratinolytic activity of two Ascomycota NSM (Guignardia mangiferae and Hypoxylon sp.) and one Basidiomycota NSM (Fomitopsis cf. meliae) was equivalent to that of pathogenic fungi, while Xylaria feejeensis showed significantly higher activity (p < 0.05) than nonpathogenic endophytes. These results indicate that the pathogenic ability of NSM is species dependent; clinical isolates, especially more frequently isolated species, may be involved in disease etiology.

Recognizing filamentous basidiomycetes as agents of human disease: A review

Filamentous basidiomycetes (BM) are common environmental fungi that have recently emerged as important human pathogens, inciting a wide array of clinical manifestations that include allergic and invasive diseases. We reviewed 218 reported global cases of BM fungi. The most common etiologic agent was Schizophyllum commune in 52.3% (114/218) of the cases followed by Hormographiella aspergillata (n = 13; 5.9%), Ceriporia lacerata (n = 11; 5%), and, rarely, Volvariella volvacea, Inonotus tropicalis, Irpex lacteus, Phellinus undulates, Perenniporia species, Bjerkandera adusta, Sporotrichum pruinosum, Phanerochaete steroids, and Cyclomyces tabacinus. These fungi are present in the environment as gilled mushrooms, shelf fungi, and bracket fungi. However, in clinical settings, they usually present as nonsporulating white moulds that are difficult to identify. Moreover, the GenBank database of these fungi is limited. Regarding the country-wise distribution of cases, Japan topped the list with about 43% (n = 94) of globally reported cases, followed by India (57; 26%), the United States (4%), Austria (3.2%), Iran (3.2%), France (2.8%), and the remaining one-third from 16 other countries. The respiratory tract was the most commonly afflicted site (n = 71), with the majority of the cases (42; 59.1%) being allergic in etiology and comprising 34 cases of allergic bronchopulmonary mycosis. Also, B. adusta has been implicated in a recently described clinical entity, that is, fungus associated chronic cough, reported exclusively from Japan. BM fungi-incited diseases are currently underdiagnosed due to lack of awareness and expertise, warranting comprehensive epidemiological and susceptibility studies to determine their prevalence and to predict a more appropriate therapy.

A case of invasive pulmonary infection caused by novel species of Perenniporia

Perenniporia species, members of basidiomycetes, are known as decay fungi from wood of hardwood tree species. The clinical significance of these non-sporulating fungi from respiratory tract specimens is unknown. They have frequently been discarded as contaminants. There was only one case report of pulmonary fungal ball with positive culture for a Perenniporia species. We report herein a case of invasive pulmonary infection caused by the novel species of Perenniporia in a 44-year-old woman with active systemic lupus erythematosus who was successfully treated with voriconazole.

Clinical significance and molecular characterization of nonsporulating molds isolated from the respiratory tracts of bronchopulmonary mycosis patients with special reference to basidiomycetes

Nonsporulating molds (NSMs), especially basidiomycetes, have predominantly been reported as human pathogens responsible for allergic and invasive disease. Their conventional identification is problematic, as many isolates remain sterile in culture. Thus, inconclusive culture reports might adversely affect treatment decisions. The clinical significance of NSMs in pulmonary mycoses is poorly understood. We sequenced the internal transcribed spacer (ITS) region and D1/D2 domain of the larger subunit (LSU) of 52 NSMs isolated from respiratory specimens. The basidiomycetes were the predominant NSMs, of which Schizophyllum commune was the most common agent in allergic bronchopulmonary mycosis (ABPM), followed by Ceriporia lacerata in invasive fungal disease. Porostereum spadiceum, Phanaerochaete stereoides, Neosartorya fischeri, and Marasmiellus palmivorus were the other molds observed. Application of ITS and LSU region sequencing identified 92% of the isolates. The antifungal susceptibility data revealed that all basidiomycetes tested were susceptible to amphotericin B and resistant to caspofungin, fluconazole, and flucytosine. Except for 3 isolates of S. commune and a solitary isolate of M. palmivorus, all basidiomycetes had low MICs for itraconazole, posaconazole, and voriconazole. Basidiomycetes were isolated from patients with ABPM, invasive pulmonary mycosis/pneumonia, or fungal balls. In addition, the majority of the basidiomycetes were isolated from patients with chronic respiratory disorders who were sensitized to one of the basidiomycetous fungi and demonstrated precipitating antibodies against the incriminating fungi, indicating an indolent tissue reaction. Thus, isolation of basidiomycetes from the lower respiratory tract could be significant, and it is important to monitor these patients in order to prevent subsequent lung damage.

Filamentous Basidiomycetes in the Clinical Laboratory

Filamentous basidiomycetes are difficult to identify in the clinical laboratory, mostly due to lack of sporulation, and their role as agents of fungal infection can be difficult to assess. More cases of infection with these agents are being reported as more laboratories gain proficiency with the recognition of their subtle morphologic features and the use of DNA-based methods for identification. Most infections occur in the respiratory tract and sinuses, although brain infection has been reported. Susceptibility testing suggests that these agents will respond well to azole drugs other than fluconazole.

Clinical significance of filamentous basidiomycetes illustrated by isolates of the novel opportunist Ceriporia lacerata from the human respiratory tract

The filamentous basidiomycete Ceriporia lacerata, an agent of white rot on wood, has never been reported in human disease and its clinical significance is not yet known. We describe 4 patients with respiratory diseases where C. lacerata was implicated in a wide spectrum of clinical manifestations ranging from saprobic colonization to fungal pneumonia. The isolates did not show the morphological characteristics that facilitate recognition of filamentous basidiomycetes, such as the presence of clamp connections, spicules along hyphae, or fruiting bodies. The identity of the mold was confirmed by sequencing the internal transcribed spacer 1 and 4 (ITS-1 and ITS-4) and D1/D2 regions of the rRNA gene. All of the isolates exhibited the lowest MICs of posaconazole and isavuconazole (MIC range, 0.06 to 0.125 μg/ml), followed by itraconazole (MIC range, 0.06 to 0.5 μg/ml), voriconazole (MIC range, 0.125 to 0.5 μg/ml), and amphotericin B (MIC range, 0.25 to 1 μg/ml). The infections reported here occurred in patients with preexisting lung damage induced by tuberculosis or chronic obstructive pulmonary disease. Chronic, sometimes fatal infections by the ascomycete Aspergillus fumigatus and the basidiomycete Schizophyllum commune are well established in the presence of an anatomical pulmonary defect or in the background of immunodeficiency. It is postulated that C. lacerata, a novel opportunist basidiomycete, may be involved in similar pathological processes.