Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 156
Filter
1.
Article in English | MEDLINE | ID: mdl-38713196

ABSTRACT

The genus Exophiala is polymorphic, able to transition between yeast, hyphal and pseudohyphal forms. Species of the genus Exophiala are ubiquitous fungi that are distributed in various environments around the world. During a survey of fungal diversity in the gut of amphipods (Floresorchestia amphawaensis and undescribed Dogielinotid amphipods) from the Amphawa estuary, Samut Songkhram province, Thailand, five black yeast strains (DMKU-MG01, DMKU-MG07, DMKU-MG08, DMKU-HG10 and DMKU-FG04) were identified as representing a novel taxon on the basis of a combination of morphological and molecular phylogenetic features. The five strains did not produce filamentous hyphae or pseudohyphae. Only budding yeast cells were observed. On the basis of the phenotypic characteristics and the results of molecular analyses of the D1/D2 region of the large subunit (LSU) rRNA gene and the internal transcribed spacer (ITS) region, the five strains were identified as representing a novel species via applied nucleotide pairwise analysis. They differed from the most closely related species Exophiala alcalophiala by 3.54 % nucleotide substitutions (20 nucleotide substitutions in 572 bp) in the D1/D2 domains of the LSU rRNA gene. Moreover, the sequences of the ITS region of the five strains differed from those of the most closely related species E. alcalophiala, by 7.44-9.62 % nucleotide substitutions, and Exophiala halophiala, by 7.2-7.53 % nucleotide substitutions. The results of phylogenetic analyses based on the concatenated sequences of the ITS regions and the D1/D2 domains of the LSU rRNA gene confirmed that the five black yeast strains represented a single novel species of the genus Exophiala. In this study, Exophiala amphawaensis sp. nov. is proposed to accommodate these strains. The holotype is TBRC 15626T and the isotype is PYCC9020. The MycoBank accession number of the novel species is MB 851477.


Subject(s)
Amphipoda , DNA, Fungal , DNA, Ribosomal Spacer , Exophiala , Phylogeny , Sequence Analysis, DNA , Animals , Thailand , Amphipoda/microbiology , DNA, Fungal/genetics , DNA, Ribosomal Spacer/genetics , Exophiala/genetics , Exophiala/isolation & purification , Exophiala/classification , Mycological Typing Techniques , Gastrointestinal Tract/microbiology
2.
PLoS One ; 19(2): e0297232, 2024.
Article in English | MEDLINE | ID: mdl-38354109

ABSTRACT

Exophiala is a black fungi of the family Herpotrichiellaceae that can be found in a wide range of environments like soil, water and the human body as potential opportunistic pathogen. Some species are known to be extremophiles, thriving in harsh conditions such as deserts, glaciers, and polluted habitats. The identification of novel Exophiala species across diverse environments underlines the remarkable biodiversity within the genus. However, its classification using traditional phenotypic and phylogenetic analyses has posed a challenges. Here we describe a novel taxon, Exophiala chapopotensis sp. nov., strain LBMH1013, isolated from oil-polluted soil in Mexico, delimited according to combined morphological, molecular, evolutionary and statistics criteria. This species possesses the characteristic dark mycelia growing on PDA and tends to be darker in the presence of hydrocarbons. Its growth is dual with both yeast-like and hyphal forms. LBMH1013 differs from closely related species such as E. nidicola due to its larger aseptate conidia and could be distinguished from E. dermatitidis and E. heteromorpha by its inability to thrive above 37°C or 10% of NaCl. A comprehensive genomic analyses using up-to-date overall genome relatedness indices, several multigene phylogenies and molecular evolutionary analyzes using Bayesian speciation models, further validate its species-specific transition from all current Exophiala/Capronia species. Additionally, we applied the phylophenetic conceptual framework to delineate the species-specific hypothesis in order to incorporate this proposal within an integrative taxonomic framework. We believe that this approach to delimit fungal species will also be useful to our peers.


Subject(s)
Ascomycota , Exophiala , Humans , Exophiala/genetics , Saccharomyces cerevisiae , Phylogeny , Mexico , Bayes Theorem
3.
Mycopathologia ; 189(1): 5, 2024 Jan 17.
Article in English | MEDLINE | ID: mdl-38231292

ABSTRACT

The opportunistic black yeast-like fungus Exophiala dermatitidis frequently colonizes the respiratory tract of cystic fibroses (CF) patients. Additionally, it can cause superficial, systemic, and cerebral forms of phaeohyphomycoses. The objective of this study was to develop and apply a microsatellite or short tandem repeat (STR) genotyping scheme for E. dermatitidis. In total, 82 E. dermatitidis isolates from various geographic origins (environmental = 9, CF = 63, invasive isolates = 9, melanin-deficient mutant = 1) were included in this study. After next-generation sequencing of a reference strain and sequence filtering for microsatellites, six STR markers were selected and amplified in two multiplex PCR reactions. The included isolates were discriminated in a genetic cluster analysis using the Pearson algorithm to reveal the relatedness of the isolates. The E. dermatitidis isolates clustered on basis of both, their source and their origin. The invasive isolates from Asia were unrelated to isolates from CF. Nearly all environmental isolates were grouped separately from patients' isolates. The Simpson index was 0.94. In conclusion, we were able to establish a STR genotyping scheme for investigating population genomics of E. dermatitidis.


Subject(s)
Cystic Fibrosis , Exophiala , Humans , Exophiala/genetics , Asia , Cluster Analysis , Microsatellite Repeats
4.
J Mycol Med ; 34(1): 101455, 2024 Mar.
Article in English | MEDLINE | ID: mdl-38042015

ABSTRACT

Exophiala dermatitidis is a relatively common environmental black yeast with a worldwide distribution that rarely causes fungal infection. Here, we report a case of a 6-year-old girl with central nervous system (CNS) encephalitis caused by E. dermatitidis and Angiostrongylus cantonensis. E. dermatitidis was identified by both cerebrospinal fluid culture and metagenomic next-generation sequencing (mNGS). Angiostrongylus cantonensis infection was confirmed by an enzyme linked immunosorbent assay (ELISA). Whole exome sequencing showed that this previously healthy girl carried a homozygous CARD9 mutation for c.820dupG (p.D274Gfs*61) that underlies invasive fungal and parasite infections. We chose glucocortieoid pulse therapy and anti-infective therapy based on the initial results of laboratory examination and cranial MRI images. With the aggravation of the disease and the evidence of the subsequent etiologic test, the combination of antifungal antiparasitic treatments (voriconazole, fluorocytosine and amphotericin B) were actively used. Unfortunately, the girl finally died due to severe systemic infection. mNGS performs a potential value for diagnosing rare CNS infections, and autosomal recessive CARD9 deficiency should be considered in patient with fatal invasive fungal infections.


Subject(s)
Angiostrongylus cantonensis , Candidiasis, Chronic Mucocutaneous , Exophiala , Child , Animals , Female , Humans , Angiostrongylus cantonensis/genetics , Central Nervous System , Exophiala/genetics , CARD Signaling Adaptor Proteins/genetics
5.
Med Mycol ; 61(8)2023 Aug 02.
Article in English | MEDLINE | ID: mdl-37591630

ABSTRACT

In cystic fibrosis (CF) patients, fungal colonization of the respiratory tract is frequently found. Aspergillus fumigatus, Scedosporium genus, and Exophiala dermatitidis are the most commonly isolated moulds from the respiratory tract secretions of CF patients. The aim of this 5-year surveillance study was to identify trends in species distribution and susceptibility patterns of 212 mould strains identified as Aspergillus spp., Scedosporium spp., and Exophiala spp., isolated from sputum of 63 CF patients who received long-term therapy with itraconazole (ITR) and/or voriconazole (VRC). The Aspergillus isolates were identified as members of the sections Fumigati (n = 130), Flavi (n = 22), Terrei (n = 20), Nigri (n = 8), Nidulantes (n = 1), and Usti (n = 1). Among the 16 species of the genus Scedosporium, 9 were S. apiospermum, 3 S. aurantiacum, and 4 S. boydii. Among the 14 Exophiala species, all were molecularly identified as E. dermatitidis. Overall, 94% (15/16) of Scedosporium spp., 50% (7/14) of E. dermatitidis, and 7.7% (14/182) of Aspergillus spp. strains showed high MIC values (≥8 µg/ml) for at least one antifungal. Particularly, 8.9% (19/212) of isolates showed high MIC values for amphotericin B, 11.7% (25/212) for ITR, 4.2% (9/212) for VRC, and 3.3% (7/212) for posaconazole. In some cases, such as some A. fumigatus and E. dermatitidis isolates recovered from the same patient, susceptibility to antifungal azoles decreased over time. We show that the use of azoles for a long time in CF patients causes the selection/isolation of mould strains with higher MIC values.


The use of azoles for a long time in cystic fibrosis patients causes the selection/isolation of Aspergillus, Scedosporium, and Exophiala species with higher MIC values.


Subject(s)
Cystic Fibrosis , Exophiala , Scedosporium , Animals , Antifungal Agents/pharmacology , Antifungal Agents/therapeutic use , Amphotericin B/pharmacology , Amphotericin B/therapeutic use , Cystic Fibrosis/complications , Cystic Fibrosis/veterinary , Exophiala/genetics , Triazoles/pharmacology , Triazoles/therapeutic use , Itraconazole , Voriconazole/pharmacology , Voriconazole/therapeutic use , Aspergillus , Azoles
6.
G3 (Bethesda) ; 13(8)2023 08 09.
Article in English | MEDLINE | ID: mdl-37293838

ABSTRACT

Individuals with cystic fibrosis (CF) are susceptible to chronic lung infections that lead to inflammation and irreversible lung damage. While most respiratory infections that occur in CF are caused by bacteria, some are dominated by fungi such as the slow-growing black yeast Exophiala dermatitidis. Here, we analyze isolates of E. dermatitidis cultured from two samples, collected from a single subject 2 years apart. One isolate genome was sequenced using long-read Nanopore technology as an in-population reference to use in comparative single nucleotide polymorphism and insertion-deletion variant analyses of 23 isolates. We then used population genomics and phylo-genomics to compare the isolates to each other as well as the reference genome strain E. dermatitidis NIH/UT8656. Within the CF lung population, three E. dermatitidis clades were detected, each with varying mutation rates. Overall, the isolates were highly similar suggesting that they were recently diverged. All isolates were MAT 1-1, which was consistent with their high relatedness and the absence of evidence for mating or recombination between isolates. Phylogenetic analysis grouped sets of isolates into clades that contained isolates from both early and late time points indicating there are multiple persistent lineages. Functional assessment of variants unique to each clade identified alleles in genes that encode transporters, cytochrome P450 oxidoreductases, iron acquisition, and DNA repair processes. Consistent with the genomic heterogeneity, isolates showed some stable phenotype heterogeneity in melanin production, subtle differences in antifungal minimum inhibitory concentrations, and growth on different substrates. The persistent population heterogeneity identified in lung-derived isolates is an important factor to consider in the study of chronic fungal infections, and the analysis of changes in fungal pathogens over time may provide important insights into the physiology of black yeasts and other slow-growing fungi in vivo.


Subject(s)
Cystic Fibrosis , Exophiala , Cystic Fibrosis/complications , Cystic Fibrosis/microbiology , Phylogeny , Exophiala/genetics , Lung
7.
G3 (Bethesda) ; 13(8)2023 08 09.
Article in English | MEDLINE | ID: mdl-37221014

ABSTRACT

Black yeasts are polyextremotolerant fungi that contain high amounts of melanin in their cell wall and maintain a primar yeast form. These fungi grow in xeric, nutrient depletes environments which implies that they require highly flexible metabolisms and have been suggested to contain the ability to form lichen-like mutualisms with nearby algae and bacteria. However, the exact ecological niche and interactions between these fungi and their surrounding community are not well understood. We have isolated 2 novel black yeasts from the genus Exophiala that were recovered from dryland biological soil crusts. Despite notable differences in colony and cellular morphology, both fungi appear to be members of the same species, which has been named Exophiala viscosa (i.e. E. viscosa JF 03-3 Goopy and E. viscosa JF 03-4F Slimy). A combination of whole genome sequencing, phenotypic experiments, and melanin regulation experiments have been performed on these isolates to fully characterize these fungi and help decipher their fundamental niche within the biological soil crust consortium. Our results reveal that E. viscosa is capable of utilizing a wide variety of carbon and nitrogen sources potentially derived from symbiotic microbes, can withstand many forms of abiotic stresses, and excretes melanin which can potentially provide ultraviolet resistance to the biological soil crust community. Besides the identification of a novel species within the genus Exophiala, our study also provides new insight into the regulation of melanin production in polyextremotolerant fungi.


Subject(s)
Exophiala , Melanins , Exophiala/genetics , Fungi , Ecosystem , Soil
8.
Mycoses ; 66(6): 488-496, 2023 Jun.
Article in English | MEDLINE | ID: mdl-36740746

ABSTRACT

BACKGROUND: The skin is the first line of defence against communities of resident viruses, bacteria and fungi. The composition of the microbiome might change with factors related to the environment and host. The microbiome is dominated by bacteria. Dermatophytes and yeasts are the predominant fungi that are also involved in opportunistic infections of skin, hair and nails. Among environmental fungi, Chaetothyriales (black yeasts and relatives) are enriched by hydrocarbon pollution in domesticated habitats and comprise numerous species that cause mild-to-severe disease. METHODS: We investigated the presence of black fungi in the skin microbiome by conducting an analysis in the publicly available metagenomic SRA database (NCBI). We focused on the causative agents of chromoblastomycosis and phaeohyphomycosis and used barcodes and padlock probe sequences as diagnostic tools. RESULTS: A total of 132,159,577 MB was analysed and yielded 18,360 reads that matched with 24 species of black fungi. Exophiala was the most prevalent genus, and Cyphellophora europaea was the most abundant species. CONCLUSION: This study reveals the abundant presence of Chaetothyriales on the skin without necessarily being associated with infection. Most of the detected causal agents are known from mild skin diseases, while also species were revealed that had been reported from CARD9-deficient patients.


Subject(s)
Exophiala , Microbiota , Humans , Saccharomyces cerevisiae , Metagenomics , Skin/microbiology , Exophiala/genetics , Microbiota/genetics , Fungi/genetics
9.
BMC Infect Dis ; 22(1): 433, 2022 May 04.
Article in English | MEDLINE | ID: mdl-35509001

ABSTRACT

BACKGROUND: Etiological diagnosis is a key step in the treatment of patients with rare pulmonary mycosis, and the lack of understanding of this disease and lack of specific markers for the detection of rare species, such as Exophiala dermatitidis, add to the difficulty in diagnosing the condition. Therefore, improving the diagnostic strategies for this disease is very important. CASE PRESENTATION: A 52-year-old man presented with cough, sputum production and hemoptysis; chest computed tomography (CT) revealed multiple bilateral lesions. The pathogen was unable to be identified after three biopsies. Subsequently, we performed combined tissue metagenomic next-generation sequencing (mNGS). The results of mNGS and a good therapeutic response helped to identify the causative pathogen as Exophiala dermatitidis. Finally, the patient was diagnosed with Exophiala dermatitidis pneumonia. CONCLUSIONS: Combining molecular techniques, such as mNGS, with clinical microbiological tests will improve the rate of positivity in the diagnosis of rare fungal infections, and the importance of follow-up should be emphasized.


Subject(s)
Exophiala , Mycoses , Pneumonia , Biopsy , Exophiala/genetics , Humans , Male , Middle Aged
11.
Med Mycol J ; 63(1): 1-9, 2022.
Article in English | MEDLINE | ID: mdl-35228479

ABSTRACT

In this study, we aimed to clarify the phylogenetic distribution of Exophiala dermatitidis in Japan and describe the characteristics of genotypes. We examined 67 clinical and environmental isolates that were morphologically identified and preserved as E. dermatitidis and we confirmed the identification on the basis of the ribosomal DNA internal transcribed spacer region. Genotype sequences were aligned and compared using maximum likelihood phylogenetic tree analyses of the ITS1 region. Additionally, the strains of each genotype were tested for mycological characteristics, such as growth temperature, growth rate, and drug sensitivity. The 67 strains examined were isolated from Japan, the United States, Brazil, Venezuela, and China. In accordance with the establishment of a phylogenetic tree for the ITS1 region, 45 of the 49 Japanese strains were classified as genotype A, two as genotype B, and two as genotype D (A2 according to the method of Matos et al. (2003)). Chinese strains were divided into genotypes A and D (A2), and South American strains were classified into genotypes A, B, B2, and C2, while all strains from the U.S. belonged to genotype A. New genotype groups B2 and C2 were identified in Brazilian and Venezuelan strains, respectively. There were no specific differences among the genotypes or isolated regions in the antifungal susceptibility test for all E. dermatitidis isolates. However, genotypes B2 and D (A2) exhibited growth at higher temperatures than the other genotypes.


Subject(s)
Exophiala , DNA, Fungal/genetics , Exophiala/genetics , Genotype , Japan , Phylogeny
12.
Mycopathologia ; 187(2-3): 259-269, 2022 Jun.
Article in English | MEDLINE | ID: mdl-35314920

ABSTRACT

Exophiala spp. is increasingly reported as a pathogen causing the cutaneous, subcutaneous or invasive infection. In this report, we present a case of cutaneous phaeohyphomycosis due to E. jeanselmei on the right hand of a farmer, who suffered from this disease three years ago which had not been definitely diagnosed until he was admitted to our hospital. In our hospital, a potential fungal pathogen was observed by histopathological examination, and then was recovered and identified as E. jeanselmei by sequencing its internal transcribed spacer region. After 4 weeks of antifungal treatment, his hand recovered very well. To investigate the in vitro susceptibility of E. jeanselmei isolates to antifungal agents and compare the characteristics of their related infections among immunocompetent and immunocompromised patients, we reviewed 84 cases published in PubMed database between 1980 and 2020.


Subject(s)
Exophiala , Phaeohyphomycosis , Antifungal Agents/pharmacology , Antifungal Agents/therapeutic use , Exophiala/genetics , Humans , Immunocompromised Host , Male , Phaeohyphomycosis/diagnosis , Phaeohyphomycosis/drug therapy , Phaeohyphomycosis/microbiology , Skin
13.
Int J Syst Evol Microbiol ; 71(11)2021 Nov.
Article in English | MEDLINE | ID: mdl-34846290

ABSTRACT

Exophiala is an important genus, with several species associated with infections in humans and animals. In a survey of soil fungal diversity in Yunnan province, PR China, a novel taxon, Exophiala pseudooligosperma sp. nov., was identified based on combined morphological and molecular phylogenetic features. Morphologically, this species is characterized by having torulose, septate hyphae and swollen, terminal or intercalary conidiogenous cells arising at acute angles from aerial hyphae. Phylogenetic analysis of the combined sequences of the internal transcribed spacer, the small and large nuclear subunit of the rRNA gene and part of the ß-tubulin gene confirmed the phylogenetic position of the new species within the genus Exophiala.


Subject(s)
Ascomycota , Exophiala , Phylogeny , Soil Microbiology , Ascomycota/classification , Ascomycota/isolation & purification , Base Composition , China , DNA, Fungal/genetics , DNA, Ribosomal Spacer/genetics , Exophiala/genetics , Mycological Typing Techniques , Sequence Analysis, DNA
14.
Mycoses ; 64(11): 1328-1333, 2021 Nov.
Article in English | MEDLINE | ID: mdl-34411353

ABSTRACT

BACKGROUND: Exophiala is the main genus of black fungi comprising numerous opportunistic species. Data on antifungal susceptibility of Exophiala isolates are limited, while infections are potentially fatal. MATERIALS AND METHODS: In vitro activities of eight antifungal drugs (AMB, five azoles, two echinocandins) against 126 clinical (n = 76) and environmental (n = 47) isolates from around the world were investigated. E. oligosperma (n = 58), E. spinifera (n = 33), E. jeanselmei (n = 14) and E. xenobiotica (n = 21) were included in our dataset. RESULTS: The resulting MIC90 s of all strains were as follows, in increasing order: posaconazole 0.063 µg/ml, itraconazole 0.125 µg/ml, voriconazole and amphotericin B 1 µg/ml, isavuconazole 2 µg/ml, micafungin and caspofungin 4 µg/ml, and fluconazole 64 µg/ml. Posaconazole, itraconazole and micafungin were the drugs with the best overall activity against Exophiala species. Fluconazole could not be considered as a treatment choice. No significant difference could be found among antifungal drug activities between these four species, neither in clinical nor in environmental isolates. CONCLUSION: Antifungal susceptibility data for Exophiala spp. are crucial to improve the management of this occasionally fatal infection and the outcome of its treatment.


Subject(s)
Antifungal Agents/pharmacology , Environmental Microbiology , Exophiala/drug effects , Phaeohyphomycosis/microbiology , Animals , Antifungal Agents/classification , Antifungal Agents/therapeutic use , Exophiala/classification , Exophiala/genetics , Humans , Microbial Sensitivity Tests , Phaeohyphomycosis/drug therapy
15.
Front Cell Infect Microbiol ; 11: 686120, 2021.
Article in English | MEDLINE | ID: mdl-34277470

ABSTRACT

Introduction: Exophiala spp. are important opportunist pathogens causing subcutaneous or even fatal disseminated infections in otherwise both immunosuppressed and healthy individuals but there are no systematic studies on the isolates of Exophiala species from India. Methods: Twenty-four isolates of Exophiala species were retrieved from the National Culture Collection of Pathogenic Fungi (NCCPF) and identified phenotypically and by molecular methods (ITS region sequencing) followed by antifungal susceptibility testing (AFST) as per CLSI-M38A3 guidelines. A review of the literature of cases from India was performed up to 1st January 2021 using the Medline and Cochrane database. Results: E. dermatitidis (n = 8), E. jeanselmei (n = 6), E. spinifera (n = 6), E. mesophila (n = 1), E. oligosperma (n = 1), E. xenobiotica (n = 1) were identified and the sequencing of ITS, ß-tubulin and ß-actin revealed a novel species, E. arunalokei sp. nov. (n = 1). The ITS sequence phylogram of E. jeanselmei revealed that the majority (83%) formed a separate cluster close to type A while majority (75%) of E. dermatitidis were type B. The MIC50 (mg/L) of amphotericin, itraconazole, voriconazole, micafungin, caspofungin, anidulafungin, and posaconazole, was 1, 0.25, 0.125, 0.12, 0.125, 0.062, and 0.062, respectively. Sixteen more cases were identified on the literature review and a significant association of E. dermatitidis with history of surgical procedures (p = 0.013), invasive disease (p = 0.032) and of E. mesophila with tuberculosis (p = 0.026) was seen. Conclusion: This, to the best of our knowledge is the first study from India elucidating the molecular and clinical characteristics of Exophiala species and the first Indian report of human infection due to E. xenobiotica and E. arunalokei.


Subject(s)
Exophiala , Amphotericin B , Antifungal Agents/pharmacology , Exophiala/genetics , Humans , India , Microbial Sensitivity Tests
16.
Med Mycol J ; 62(2): 35-39, 2021.
Article in English | MEDLINE | ID: mdl-34053978

ABSTRACT

We describe a case of recalcitrant phaeohyphomycosis caused by Exophiala lecanii-corni, which was previously reported as Exophiala jeanselmei, infection. A 63-year-old Japanese woman presented with a 15-year history of multiple pruritic erythematous patches and plaques on the face. Histopathological examination and fungal culture revealed phaeohyphomycosis by E. jeanselmei. The attempted treatments included 6 g/day 5-flucytosine (5-FC), 100 mg/day itraconazole (ITCZ), and local hyperthermia. 5-FC was effective initially, but the patient deteriorated after discontinuation. Subsequently, she was referred to our hospital. Histopathological examination showed granuloma with multinucleated giant cells with infiltrating fungal hyphae in the dermis. The causative fungus was finally identified as E. lecanii-corni by ribosomal RNA gene analysis. The patient improved after receiving 200 mg/day ITCZ orally for 15 months with local hyperthermia. In the present case, we confirmed the identification of E. lecanii-corni as the causative agent by molecular methods. We also emphasize the importance of combination therapy with antimycotic agents and local hyperthermia in phaeohyphomycosis.


Subject(s)
Exophiala , Phaeohyphomycosis , Exophiala/genetics , Female , Humans , Middle Aged , Phaeohyphomycosis/diagnosis , Phaeohyphomycosis/drug therapy
17.
Fungal Biol ; 125(6): 459-468, 2021 06.
Article in English | MEDLINE | ID: mdl-34024593

ABSTRACT

A clade where the most halotolerant fungus in the world - Hortaea werneckii, belongs (hereafter referred to as Hortaea werneckii lineage) includes five species: Hortaea werneckii, H. thailandica, Stenella araguata, Eupenidiella venezuelensis, and Magnuscella marina, of which the first species attracts increasing attention of mycologists. The species diversity and phylogenetic relationships within this lineage are weakly known. In this study two moderately halophilic black yeast strains were isolated from brine of graduation tower in Poland. Molecular phylogenetic analyses based on the rDNA ITS1-5.8S-ITS2 (=ITS), rDNA 28S D1-D2 (=LSU), and RNA polymerase II (rpb2) sequences showed that the two strains belong to Hortaea werneckii lineage but cannot be assigned to any described taxa. Accordingly, a new genus and species, Salinomyces and Salinomyces polonicus, are described for this fungus. Furthermore, molecular phylogenetic analyses have revealed that Hortaea thailandica is more closely related to S. polonicus than to H. werneckii. A new combination Salinomyces thailandicus is proposed for this fungus.


Subject(s)
Ascomycota , Phylogeny , Ascomycota/classification , Ascomycota/genetics , DNA, Fungal/genetics , DNA, Ribosomal/genetics , Exophiala/classification , Exophiala/genetics , Poland , Species Specificity
18.
J Infect Chemother ; 27(9): 1360-1364, 2021 Sep.
Article in English | MEDLINE | ID: mdl-33888421

ABSTRACT

BACKGROUND: Exophiala (Wangiella) dermatitidis is a clinically relevant black yeast. Although E. dermatitidis rarely causes human infection, it can cause superficial and deep-seated infections, and cutaneous and subcutaneous diseases. Cases of fungemia and central line-associated bloodstream infections due to E. dermatitidis are extremely uncommon, and their clinical manifestations and prognosis are still not well-known. Herein, we report a case of central line-associated bloodstream infections in a patient with cancer. These infections were caused by melanized yeast that was finally identified as E. dermatitidis via internal transcribed spacer sequencing and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. CASE PRESENTATION: A 75-year-old man with thoracic esophageal cancer and early gastric cancer presented with a 1-day history of fever during his hospitalization at our hospital. A central venous port was placed in the patient for total parenteral nutrition. Two E. dermatitidis isolates were recovered from two blood samples drawn at different times from a peripheral vein and this central venous port. The isolate was identified as E. dermatitidis by internal transcribed spacer sequencing and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. The central venous port was removed, and the patient was administered micafungin and voriconazole. Although the minimum inhibitory concentrations of E. dermatitidis for voriconazole and minimum effective concentrations for micafungin were 2 µg/mL and 4 µg/m, respectively, the bacteremia was successfully treated. CONCLUSIONS: Although no clear treatment guidelines have been proposed for E. dermatitidis infections, immediate removal of central venous catheters is the key to improving central line-associated bloodstream infections.


Subject(s)
Bacteremia , Exophiala , Neoplasms , Aged , Exophiala/genetics , Humans , Male , Neoplasms/complications , Voriconazole
19.
BMC Microbiol ; 21(1): 40, 2021 02 05.
Article in English | MEDLINE | ID: mdl-33546601

ABSTRACT

BACKGROUND: Melatonin (MT), ubiquitous in almost all organisms, functions as a free radical scavenger. Despite several reports on its role as an antioxidant in animals, plants, and some microorganisms, extensive studies in filamentous fungi are limited. Based upon the role of melatonin as an antioxidant, we investigated its role in heavy metal-induced stress tolerance in Exophiala pisciphila, a dark septate endophyte (DSE), by studying the underlying mechanisms in alleviating oxidative stress and reducing heavy metal accumulation. RESULTS: A significant decrease in malondialdehyde (MDA) and oxygen free radical (OFR) in E. pisciphila was recorded under Cd, Zn, and Pb stresses as compared to the control. Pretreatment of E. pisciphila with 200.0 µM exogenous melatonin significantly increased the activity of superoxide dismutase (SOD) under Zn and Pb stresses. Pretreatment with 200.0 µM melatonin also lowered Cd, Zn, and Pb concentrations significantly. Melatonin production was enhanced by Cd, Cu, and Zn after 2 d, and melatonin biosynthetic enzyme genes, E. pisciphila tryptophan decarboxylase (EpTDC1) and serotonin N-acetyltransferase (EpSNAT1), were transcriptionally upregulated. The overexpression of EpTDC1 and N-acetylserotonin O-methyltransferase (EpASMT1) in Escherichia coli and Arabidopsis thaliana enhanced its heavy metal-induced stress tolerance. The overexpression of EpTDC1 and EpASMT1 reduced the Cd accumulation in the whole A. thaliana plants, especially in the roots. CONCLUSIONS: Melatonin conferred heavy metal-induced stress tolerance by alleviating oxidative stress, activating antioxidant enzyme SOD, and reducing heavy metal accumulation in E. pisciphila. Melatonin biosynthetic enzyme genes of E. pisciphila also played key roles in limiting excessive heavy metal accumulation in A. thaliana. These findings can be extended to understand the role of melatonin in other DSEs associated with economically important plants and help develop new strategies in sustainable agriculture practice where plants can grow in soils contaminated with heavy metals.


Subject(s)
Exophiala/drug effects , Exophiala/metabolism , Melatonin/pharmacology , Metals, Heavy/metabolism , Oxidative Stress/drug effects , Antioxidants/pharmacology , Biosynthetic Pathways/genetics , Exophiala/genetics , Melatonin/biosynthesis , Melatonin/genetics , Oxidative Stress/genetics , Soil Pollutants
20.
Rev Iberoam Micol ; 38(1): 12-15, 2021.
Article in English | MEDLINE | ID: mdl-33279387

ABSTRACT

BACKGROUND: Exophiala dermatitidis is a dematiaceous fungus known to cause superficial, subcutaneous, cutaneous and deep seated infections, and rarely central line associated bloodstream infection (CLABSI). A case of CLABSI due to E. dermatitidis in an infant is described. CASE REPORT: Clinical and laboratory data were extracted from patient's chart and laboratory records. The isolate was identified as E. dermatitidis by phenotypic characterization and sequencing of the ITS and LSU regions of the ribosomal DNA. Medline search was done to review all cases of CLABSI due to E. dermatitidis. Among the azoles tested, posaconazole (0.06mg/l), voriconazole (0.03mg/l) and itraconazole (0.03mg/l) showed very low MICs when compared to fluconazole (4mg/l) CONCLUSIONS: As we did not found in the literature any case of CLABSI due to E. dermatitidis in an infant, we report the first one. Sequencing is a mandatory method for accurately identifying this species. Prompt removal of the central line, followed by a treatment with amphotericin B or an azole, seems to be the most effective treatment.


Subject(s)
Exophiala , Phaeohyphomycosis , Sepsis , Antifungal Agents/therapeutic use , Exophiala/genetics , Humans , Infant , Phaeohyphomycosis/diagnosis , Phaeohyphomycosis/drug therapy , Sepsis/drug therapy
SELECTION OF CITATIONS
SEARCH DETAIL
...