Death by edible mushroom: first report of Volvariella volvacea as an etiologic agent of invasive disease in a patient following double umbilical cord blood transplantation

Increase in the incidence of invasive fungal infections due to Volvariella Volvacea

PURPOSE

We aimed to show the increasing incidence of invasive fungal infections due to Volvariella Volvacea in patients with immunosuppression.

METHODS

We present a case of an invasive fungal infection caused by Volvariella volvacea, and summarize the clinical and pathological features based on this case and a review of the literature.

RESULTS

A total of seven patients with IFIs due to Volvariella Volvacea have been reported in the literature. The majority of cases have been obtained between 2019 and 2022. Including our case, they all had acquired immunosuppression. The lung and brain were the most commonly affected organs. All eight of these patients received antifungal therapy, but five still died one to seven months after occurrences of IFIs.

CONCLUSION

The incidence of invasive fungal infections due to Volvariella Volvacea is increasing in recent years. It mainly occurred in patients with immunosuppression, especially in patients with malignant hematological cancers, and increased mortality.

Isolation of filamentous basidiomycetes from respiratory samples in a tertiary care Spanish hospital

BACKGROUND

The clinical significance of the filamentous basidiomycetes isolated from clinical samples is not always clear. Thus, these fungi have been considered environmental contaminants traditionally.

AIMS

To review those clinical cases in which filamentous basidiomycetes from respiratory samples had been isolated.

METHODS

The retrospective study was carried out in a single tertiary care hospital. We recovered all culture-confirmed isolations of filamentous basidiomycetes from respiratory samples (bronchial aspirate [BAS], bronchoalveolar lavage [BAL] and sputum) analyzed between the years 2020 and 2023. Isolates were identified by ITS region sequencing.

RESULTS

In six patients a filamentous basidiomycete had been isolated from a respiratory sample. The species identified were all different: Fomitopsis sp. (BAS), Trametes ljubarskyi (BAL), Stereum gausapatum (BAS), Porostereum spadiaceum (BAS), Phlebia subserialis (sputum) and Inonotus levis (BAL). All the patients were immunosuppressed or had an underlying disease with pulmonary involvement. None of them received any specific antifungal treatment (in relation with the fungus isolated) and all six improved clinically and were discharged.

CONCLUSIONS

The isolation of filamentous basidiomycetes in these patients had uncertain clinical significance. However, the isolation of any filamentous basidiomycete in respiratory samples from immunosuppressed patients or patients with chronic pulmonary disease is an emerging situation that should be carefully assessed in the context of chronic allergic episodes or suspicion of invasive fungal infections.

Gloeostereum cimri, a novel shelf fungus isolated from a human pulmonary cyst

Filamentous basidiomycetes are uncommon agents of human diseases, despite their ubiquitous presence in the environment. We present a case of symptomatic pulmonary infection in a 38-year-old male with cough and fever; a thin-walled cyst in the posterior left upper pulmonary lobe was revealed by radiography. A non-sporulating fungus was isolated from sputum and biopsy material from the cyst. ITS and LSU sequences placed the fungus phylogenetically in Agaricales, family Cyphellaceae, and identified it as a member of shelf fungi in Gloeostereum, but without identity to any known species. The new species is described as Gloeostereum cimri. The clinical strain showed high MIC to voriconazole (>8 µg/ml) but had low MIC to amphotericin B (0.5 µg/ml).

First case report of fungal meningitis due to a polypore mushroom Irpex lacteus

A 73-year-old Japanese man with a medical history of sarcoidosis was diagnosed with meningitis caused by an undetermined fungus. For further identification, the cerebrospinal fluid sample was analyzed for the rDNA internally transcribed spacer regions, and the fungus was identified as Irpex lacteus. I. lacteus is classified under phylum Basidiomycota and is a wood-rotting bracket mushroom. Although there is no standard treatment regimen for I. lacteus infections, amphotericin B was effective in this patient. Herein, we present, to our knowledge, the first reported case of fungal meningitis caused by I. lacteus, its treatment course, and review relevant published literature.

Alterations in gut bacterial and fungal microbiomes are associated with bacterial Keratitis, an inflammatory disease of the human eye

Dysbiosis, or imbalance in the gut microbiome, has been implicated in auto-immune, inflammatory, neurological diseases as well as in cancers. More recently it has also been shown to be associated with ocular diseases. In the present study, the association of gut microbiome dysbiosis with bacterial Keratitis, an inflammatory eye disease which significantly contributes to corneal blindness, was investigated. Bacterial and fungal gut microbiomes were analysed using fecal samples of healthy controls (HC, n = 21) and bacterial Keratitis patients (BK, n = 19). An increase in abundance of several antiinflammatory organisms including Dialister, Megasphaera, Faecalibacterium, Lachnospira, Ruminococcus and Mitsuokella and members of Firmicutes, Veillonellaceae, Ruminococcaceae and Lachnospiraceae was observed in HC compared to BK patients in the bacterial microbiome. In the fungal microbiome, a decrease in the abundance of Mortierella, Rhizopus, Kluyveromyces, Embellisia and Haematonectria and an increase in the abundance of pathogenic fungi Aspergillus and Malassezia were observed in BK patients compared to HC. In addition, heatmaps, PCoA plots and inferred functional profiles also indicated significant variations between the HC and BK microbiomes, which strongly suggest dysbiosis in the gut microbiome of BK patients. This is the first study demonstrating the association of gut microbiome with the pathophysiology of BK and thus supports the gut-eye axis hypothesis. Considering that Keratitis affects about 1 million people annually across the globe, the data could be the basis for developing alternate strategies for treatment like use of probiotics or fecal transplantation to restore the healthy microbiome as a treatment protocol for Keratitis.

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.

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.

Ustilago as a Cause of Fungal Peritonitis: Case Report and Review of the Literature

Fungal peritonitis is an uncommon complication of ambulatory peritoneal dialysis in children and often necessitates catheter removal, prolonged hospitalization and conversion to hemodialysis. The majority of these infections are due to Candida albicans and related species. We present an uncommon case of peritonitis due to the unusual plant pathogen Ustilago.

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

Perenniporia species are basidiomycetes, resupinate shelf fungi responsible for white rot decay of wood. Here, we report for the first time an intracavitary pulmonary fungal ball due to a species of Perenniporia that has not been recognized so far as a human pathogen. The fungus was identified by sequencing of the partial ribosomal operon of a culture from a clinical specimen.