Nucleotide Sequencing for Diagnosis of Sinusal Infection by Schizophyllum commune , an Uncommon Pathogenic Fungus

Abstract

Schizophyllum commune, a basidiomycete fungus, is a rare cause of mycotic disease. We report here a case of sinusitis in a 35-year-old woman that underscores the value of molecular biology for the diagnosis of this fungal infection. CASE REPORTA 35-year-old Caucasian woman presented to the Department of Otorhinolaryngology, Rangueil University Hospital, Toulouse, France. She complained of a predominantly rightsided nasal obstruction, accompanied by thick, right-sided mucopurulent rhinorrhea and headaches. There was no history of asthma or other allergic diseases, medical or surgical treatment, smoking, or drug abuse. No potential risk factor such as diabetes mellitus, immunodeficiency, or previous facial trauma was determined after questioning the patient. Laboratory investigations did not show neutrophil white cells in the nasal mucus, any blood eosinophilia, or any increase of the inflammation markers.Endoscopic examination of the nasal fossae found a rightsided septal deviation, without any anomaly of the mucosa or any abnormal secretions from the middle meatus. A sinus computed tomographic scan showed an isolated heterogeneous opacity, filling the right ethmoid, with thinning bony walls (Fig. 1). The dental examination showed no infectious sites.An endonasal endoscopic surgical treatment was undertaken that included both right ethmoidectomy and septoplasty. Gross examination of ethmoidal cells found them filled with thick, viscous, and brown tinted secretions evocative of a fungal infection. The immediate postoperative course was simple, with nasal packing removed on the first postoperative day.Microscopy examination of the secretions showed the presence of thin, septate hyphae with a width ranging from 1.5 m to 3 m and without any particular features (Fig. 2). After treatment by Digest'EUR (Eurobio, France), a mucolytic agent, the specimen was inoculated in four tubes containing Sabouraud-chloramphenicol-gentamicin agar medium (BioRad, France). After 6 days at 32°C, growth of a white, cottony mold with a pale brown reverse was observed. This mold produced a strong and disagreeable smell. Microscopic examination of the mycelium showed hyaline, septate, branched hyphae without clamp connections, spicules, or fruiting bodies. Subcultures on home-made malt (2% malt extract [Merck, Germany], 1.4% Pastagar [Bio-Rad, France], 0.05% Thiophenicol [Sanofi-Synthelabo, France], 100 ml of distilled sterile water) and potato-carrot agar (PC) media yielded the same results, apart from the presence of swellings and chlamydospores on the malt agar medium. These elements were insufficient for an optical identification of the fungus that was therefore labeled as "sterile mycelium."In order to reach a diagnosis by molecular biology, a fragment of the surgical specimen was disrupted by using the MagNA Lyser system based on the collision of ceramic beads (Roche Diagnostics, Germany). Genomic DNA was then extracted by using the High-Pure PCR template preparation kit (Roche Diagnostics, Germany). Cycle sequencing was performed on ...

First report of otitis externa caused by Schizophyllum commune and review of the literature

“…However, S. commune can also be found in monocaryotic status, which lacks these typical characteristics. In these cases, it is much more difficult to identify the isolate as S. commune [20,21]. The fungus isolated from the first swab was lacking speciesspecific morphology and it was, therefore, considered as a contaminant, since non-sporulating filamentous fungi are not the usual cause of otitis externa.…”

Sinusitis and frontal brain abscess in a diabetic patient caused by the basidiomycete Schizophyllum commune: case report and review of the literature

“…After introduction of these new methods we found twelve isolates of this basidiomycetous fungus within a 3‐year‐period, all obtained from patients suffering from chronic sinusitis 10 . After introduction of nucleotide sequencing the frequency of S. commune isolation from clinical samples has increased 1,5–6,11–12,15,18,21,22 . Antifungal susceptibility testing has rarely been performed for S. commune.…”

“…10 After introduction of nucleotide sequencing the frequency of S. commune isolation from clinical samples has increased. 1,[5][6][11][12]15,18,21,22 Antifungal susceptibility testing has rarely been performed for S. commune. The use of the Etest method was preferred against microdilution methods (CLSI, EUCAST) because of the unproblematic availability of the test antimycotics and the ease of use of the method.…”

Molecular Identification of Schizophyllum commune as a Cause of Allergic Fungal Sinusitis

“…At the time of this report, only 25 cases of AFS have been reported worldwide [14-24]. Interestingly, most cases of S. commune have been reported in Japan.…”