Molecular identification of Schizophyllum commune as a cause of allergic fungal sinusitis

Allergic fungal rhinosinusitis: What we can learn from allergic bronchopulmonary mycosis

Allergic fungal rhinosinusitis (AFRS) and allergic bronchopulmonary mycosis (ABPM) are inflammatory disorders of the respiratory tract resulting from type 1 and 3 hypersensitivity reactions against fungi. The hallmark features of both diseases are eosinophil infiltration into the airway mucosa caused by localized type 2 inflammation and concomitant viscid secretions in the airways. Eosinophilic mucin-induced compression of adjacent anatomic structures leads to bone erosion and central bronchiectasis in the upper and lower respiratory tracts, respectively. Although these diseases share common features in their pathogenesis, they also exhibit notable differences. Epidemiologic findings are diverse, with AFRS typically presenting at a younger age, exhibiting less complicated bronchial asthma, and displaying lower total immunoglobulin E levels in laboratory findings compared with ABPM. Furthermore, despite their similar pathogenesis, the rarity of sinio-bronchial allergic mycosis in both AFRS and ABPM underscores the distinctions between these two diseases. This review aims to clarify the similarities and differences in the pathogenesis of AFRS and ABPM to determine what can be learned about AFRS from ABPM, where more is known.

A case of allergic fungal rhinosinusitis caused by Schizophyllum commune identified in both patient's nasal sputum and veranda's soil samples

This is a case report of allergic fungal rhinosinusitis caused by Schizophyllum commune (S. commune) identified in a patient's nasal mucus and environmental soil sample using (r)DNA sequencing. Although filamentous basidiomycetes, including S. commune, are known as environmental pathogens causing allergic respiratory diseases worldwide, many patients with infections caused by S. commune have not been correctly diagnosed. Repeated exposures to environmental floating fungi supposedly make an easy sensitization and colonization of fungi in the nasal passages, resulting in the onset of allergic fungal rhinosinusitis due to S. commune in our living environments. This report indicates the importance of reconsidering allergic respiratory diseases associated with our living environments.

Genetic Diversity and Dye-Decolorizing Spectrum of Schizophyllum commune Population

Synthetic dyes are widely used in various industries and their wastage causes severe environmental problems while being hazardous to human health, leading to the need for eco-friendly degradation techniques. The split-gill fungus Schizophyllum commune, which is found worldwide, has the potential to degrade all components of the lignocellulosic biomass and is a candidate for the treatment of synthetic dyes. A systematic molecular analysis of 75 Korean and 6 foreign S. commune strains has revealed the high genetic diversity of this population and its important contribution to the total diversity of S. commune. We examined the dye decolorization ability of this population and revealed 5 excellent strains that strongly decolorized 3 dyes: Crystal Violet, Congo Red and Methylene Blue. Finally, comparison of dye decolorization ability and the phylogenetic identification of these strains generalized their genetic and physiological diversity. This study provides an initial resource for physiological and genetic research projects as well as the bioremediation of textile dyes.

Human infections due to Schizophyllumcommune: Case report and review of the literature

Schizophyllumcommune is an environmental basidiomycetous fungus, causing occasional, predominantly respiratory, infections in humans. Although S. commune is considered an emerging pathogen, some authors pointed out the possibility that the increase in the diagnosed cases may be also due to recent advances in diagnostic technologies now allowing a more prompt and precise identification at the species level. Here we describe the first Italian case of chronic non-invasive fungal rhinosinusitis due to S. commune in an immunocompetent subject and update the literature review on S. commune sinusitis published between 2012-2019. A timely diagnosis is important to avoid local and systemic complications due to infection with this fungus. In our case, prompt identification at species level was only possible with the use of MALDI-TOF mass spectrometry and confirmed by sequence analysis of ribosomal DNA ITS regions, due to the difficulty in achieving a correct and rapid identification using routine morphological analysis.

First report on cutaneous infectious granuloma caused by Schizophyllum commune

Background

Schizophyllum commune, a basidiomycetous fungus, is a common invader of rotten wood. This fungus rarely causes mycotic disease in humans, especially cutaneous infection. In this paper, we describe the first case of cutaneous granuloma caused by S. commune in a Chinese woman.

Case presentation

A 25-year-old female with a two-year history of erythema, papules, nodules, and scales on her sole of left foot was presented to our outpatient center. Samples were obtained by the scraping of lesion and for light microscopy. Hyphae were observed by microscopic examination. We carried out a skin tissue biopsy, which showed multiple granulomatous nodules. Biopsy specimens were also inoculated onto media. After being cultured on SDA at 27 °C for 7 days, spreading-woolly-white colonies grew on the inoculation sites of media containing chloramphenicol only and there^,s no other colonies grew. S. commune was identified by morphology methods, biochemical tests, and PCR sequencing. Pathological findings also aided in diagnosing cutaneous fungal granuloma. Oral itraconazole was applied. After 1 month of therapy, rashes on her left foot and pain were improved.

Conclusion

We describe the first case of cutaneous granuloma caused by Schizophyllum commune, which illustrates the importance of recognizing uncommon pathogenic fungal infections.

Direct identification of molds by sequence analysis in fungal chronic rhinosinusitis

Fungi are widely implicated in chronic rhinosinusitis. Direct microscopic examination (DME) is used to confirm the biological diagnosis of fungal rhinosinusitis (FRS). Diagnostic sensitivity of DME is better than culture, however DME does not allow fungal species identification. In this study, we included 54 sinus samples demonstrating hyphae on DME. Direct sequencing was compared to culture for the identification of the fungal species. Sequence analysis identified fungi in 81.5% of cases while culture was positive in only 31.5%. The most common genus was Aspergillus and the identified species belonged to section Fumigati or to section Flavi. Among other fungi identified by sequence analysis, Schizophyllum commune was present in three samples attesting to the importance of this Basidiomycetes in FRS. Our results clearly demonstrate the superiority of sequencing compared to culture when performed on specimens with hyphal elements at DME, and contributes to the epidemiological knowledge of fungi involved in FRS.

First isolation of Schizophyllum commune in a harbor seal (Phoca vitulina)

To date, Schizophyllum commune infection has been identified in only humans and dogs. A 7-year-old female harbor seal (Phoca vitulina) died after exhibiting corneal opacity, anorexia, and labored respiration. At necropsy, phthisis of the left eyeball was detected, and multiple nodular lesions were observed in the thoracic and abdominal regions, especially in the lung, heart, and lymph nodes. Histopathologically, numerous hyphae were seen in granulomatous lesions in the eyes, lung, heart, and lymph nodules. An isolate on potato dextrose agar from the eyes, lung, and sputum yielded a rapidly growing white woolly mycelia with basidiocarps (fruiting bodies) at 37°C. A suitable temperature for mycelial growth was obtained at 25°C, although sustained growth also occurred at 37°C. The fungal isolate, KH-JPN15-011, had distinctive features including hyphae bearing spicules and clamp connections, which were consistent with the characteristics of basidiomycete fungus. The sequence of the internal transcribed spacer region of nuclear ribosomal DNA showed 99.67% (617 bp) similarity with those of S. commune Phylogenetic analysis showed that the present isolate is most closely related to the samples from the Old World. This is the first report of a fatal disease caused by S. commune in exotic animals. Previously reported human and canine infections have not included granulomatous endophthalmitis and myocarditis. After considering these and previous findings, there is a possibility that S. commune from the Old World may include numerous highly pathogenic strains.

Contribution of molecular tools for the diagnosis and epidemiology of fungal chronic rhinosinusitis

Chronic rhinosinusitis (CRS) rank second at chronic inflammatory diseases in industrialized countries and are an important public health concern. Diagnosis relies on a set of arguments including clinical signs, imaging, histopathologic and mycological analyses of sinus specimens, collected during nasal endoscopy. The sensitivity of fungal cultures is reported to be poor, even when direct examination is positive, thus the epidemiology of fungal chronic sinusitis is ill-known. This study evaluated the sensitivity of molecular diagnosis in 70 consecutive samples (61 patients with CRS) analysed at the University Hospital of Rennes during a 3-year period. DNA detection was performed using a conventional PCR method targeting the ITS1/ITS2 sequence and the resulting amplification products were sequenced. Fungal CRS was proven in 42 patients (69%), of which only 20 (48%) had a positive culture. 37/42 (88%) patients were diagnosed with a fungus ball, 3 with allergic fungal CRS and 2 with undetermined fungal CRS. PCR was positive in all 42 cases and direct sequencing allowed to identify fungi in all cases but one, and detected multiple infection in 3. Aspergillus fumigatus was present in 69% of patients; Cladosporium cladosporoides in 9.5%, Scedosporium sp., A. nidulans and A. flavus in 7% each. In 2/19 patients with negative direct examination, sequencing analysis revealed the presence of Capnobotryella sp. and C. cladosporoides, in clinical settings compatible with fungal sinusitis. In conclusion, ITS1/ITS2 PCR had a twice better sensitivity than culture, and combined sequencing provides accurate epidemiological data on fungal CRS.

Schizophyllum commune: an emergent or misdiagnosed fungal pathogen in rhinology?

Schizophyllum commune is a common basidiomycete fungus that is rarely involved in human disease. The medical records of patients operated on for fungal rhinosinusitis (FRS) in two University Hospitals between 2012 and 2014 were reviewed. Within the two-year survey, six female, and notably no male, patients were diagnosed with S. commune rhinosinusitis. Mean age was 44.6 years at diagnosis (30 to 68 years). Mean time between onset of symptoms and diagnosis was 8.5 months (2 to 12 months). All six patients were immunocompetent and had no particular host factor for FRS. S. commune was identified using MALDI-TOF mass spectrometry and identifications were confirmed via DNA sequence analysis. Chronic invasive fungal rhinosinusitis was diagnosed in three of our six patients. Based on histological findings, antifungal treatment was delivered in association with surgery. The basidiomycete fungus S. commune is an emerging cause of rhinosinusitis probably as a direct consequence of the recent technological progress in fungal identification methods (DNA sequencing and MALDI-TOF mass spectrometry).

Schizophyllum commune-induced allergic fungal rhinosinusitis and sinobronchial mycosis

We present 32- and 38-year-old males with Schizophyllum commune-induced allergic fungal rhinosinusitis (AFRS). S. commune-induced AFRS was diagnosed by clinical and radiographic findings, positive specific IgE antibodies against S. commune as measured by the ImmunoCAP system, and sequencing analysis of the fungus. Our two cases with S. commune-induced AFRS for the first time showed evidence for type 1 hypersensitivity to S. commune as determined by using specific IgE antibodies against S. commune, and the fungus was identified by sequence analysis.

Frequency of fungal agents identified in sinus samples from patients with clinically suspected rhinosinusitis

Fungal rhinosinusitis (FRS) is one of the most important rhinosinusoidal disorders, which involves a variety of etiological agents. We carried out a study to determine the frequency of fungal agents in sinus samples from patients with clinically suspected rhinosinusitis (RS). A total of 205 clinical samples were assessed from 174 patients with clinically suspected RS, of which 48 were positive for microscopic examination and culture, 47 were positive for direct examination but negative by culture, 4 were negative for direct examination but positive by culture, and 106 were negative for both methodologies. The main fungal agents isolated were Aspergillus spp. (32.7%), followed by Schizophyllum commune (28.8%). Sensitivity and specificity of the direct examination were 92.3% and 69.3%, respectively, and concordance between the direct examination and culture was 48.4%. This study indicated that both Aspergillus and S. commune appear to be the most important agents involved in the development of FRS.

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 PKS I gene-based screening approach for the discovery of a new polyketide from Penicillium citrinum Salicorn 46

Salicorn 46, an endophytic fungus isolated from Salicornia herbacea Torr., was identified as Penicillium citrinum based on its internal transcribed spacer and ribosomal large-subunit DNA sequences using a type I polyketide synthase (PKS I) gene screening approach. A new polyketide, penicitriketo (1), and seven known compounds, including ergone (2), (3β,5α,8α,22E)-5,8-epidioxyergosta-6,9,22-trien-3-ol (3), (3β,5α,8α,22E)-5,8-epidioxyergosta-6,22-dien-3-ol (4), stigmasta-7,22-diene-3β,5α,6α-triol (5), 3β,5α-dihydroxy-(22E,24R)-ergosta-7,22-dien-6β-yl oleate (6), N b-acetyltryptamine (7), and 2-(1-oxo-2-hydroxyethyl) furan (8), were isolated from the culture of Salicorn 46, and their chemical structures were elucidated by spectroscopic analysis. Antioxidant experiments revealed that compound 1 possessed moderate DPPH radical scavenging activity with an IC50 value of 85.33 ± 1.61 μM. Antimicrobial assays revealed that compound 2 exhibited broad-spectrum antimicrobial activity against Candida albicans, Clostridium perfringens, Mycobacterium smegmatis, and Mycobacterium phlei with minimal inhibitory concentration (MIC) values of 25.5, 25.5, 18.5, and 51.0 μM, respectively. Compound 3 displayed potent antimicrobial activities against C. perfringens and Micrococcus tetragenus with a MIC value of 23.5 μM. Compounds 5 and 6 showed high levels of selectivity toward Bacillus subtilis and M. phlei with MIC values of 22.5 and 14.4 μM, respectively. The results of this study highlight the use of PCR-based techniques for the screening of new polyketides from endophytic fungi containing PKS I genes.

Fatal empyema thoracis caused by Schizophyllum commune with cross-reactive cryptococcal antigenemia

We report a fatal case of Schizophyllum commune empyema thoracis with cross-reactive cryptococcal antigenemia. In vitro testing confirmed the ability of the fungus to cause a positive cryptococcal antigen latex agglutination system (CALAS) test result. Such a result may lead to delay in diagnosis and treatment, as most strains of S. commune are resistant to fluconazole.

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.