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Fungal primary pathogenicity on vertebrates is here described as a deliberate strategy where the host plays a role in increasing the species fitness. Opportunism is defined as coincidental survival of an individual strain in host tissue using properties that are designed for life in an entirely different habitat. In that case the host's infection control is largely based on innate immunity, and the etiologic agent is not transmitted after infection, and thus fungal evolution is not possible. Primary pathogens encompass two types, depending on their mode of transmission. Environmental pathogens have a double life cycle, and tend to become enzootic, adapted to a preferred host in a particular habitat. In contrast, pathogens that have a host-to-host transmission pattern are prone to shift to a neighboring, immunologically naive host, potentially leading to epidemics. Beyond these prototypical life cycles, some environmental fungi are able to make large leaps between dissimilar hosts/habitats, probably due to similarity of key factors enabling survival in an entirely different niche, and thus allowing a change from opportunistic to primary pathogenicity. Mostly, such factors seem to be associated with extremotolerance.
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Dimorphism is known among the etiologic agents of endemic mycoses as well as in filamentous Mucorales. Under appropriate thermal conditions, mononuclear yeast forms alternate with multi-nucleate hyphae. Here, we describe a dimorphic mucoralean fungus obtained from the sputum of a patient with Burkitt lymphoma and ongoing graft-versus-host reactions. The fungus is described as Mucor germinans sp. nov. Laboratory studies were performed to simulate temperature-dependent dimorphism, with two environmental strains Mucor circinelloides and Mucor kunryangriensis as controls. Both strains could be induced to form multinucleate arthrospores and subsequent yeast-like cells in vitro. Multilateral yeast cells emerge in all three Mucor species at elevated temperatures. This morphological transformation appears to occur at body temperature since the yeast-like cells were observed in the lungs of our immunocompromised patient. The microscopic appearance of the yeast-like cells in the clinical samples is easily confused with that of Paracoccidioides. The ecological role of yeast forms in Mucorales is discussed.IMPORTANCEMucormycosis is a devastating disease with high morbidity and mortality in susceptible patients. Accurate diagnosis is required for timely clinical management since antifungal susceptibility differs between species. Irregular hyphal elements are usually taken as the hallmark of mucormycosis, but here, we show that some species may also produce yeast-like cells, potentially being mistaken for Candida or Paracoccidioides. We demonstrate that the dimorphic transition is common in Mucor species and can be driven by many factors. The multi-nucleate yeast-like cells provide an effective parameter to distinguish mucoralean infections from similar yeast-like species in clinical samples.
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Mucor , Mucormicosis , Humanos , Mucormicosis/microbiología , Mucormicosis/diagnóstico , Mucor/aislamiento & purificación , Mucor/genética , Mucor/clasificación , Paracoccidioides/aislamiento & purificación , Paracoccidioides/genética , Esputo/microbiología , Filogenia , ADN de Hongos/genética , ADN de Hongos/química , Huésped Inmunocomprometido , Masculino , Análisis de Secuencia de ADN , TemperaturaRESUMEN
Black yeasts and relatives comprise Micro-Colonial Fungi (MCFs) which are slow-growing stress-tolerant micro-eukaryotes that specialize in extreme environments. MCFs are paraphyletic and found in the Orders Chaetothyriales (Eurotiomycetes) and Dothideales (Dothidiomycetes). We have isolated and described three new MCFs species from desert biological soil crusts (BSCs) collected from two arid land regions: Joshua Tree National Park (Mojave Desert) and UC Natural Reserve at Boyd Deep Canyon (confluence of Mojave and Sonoran Deserts). BSCs are composite assemblages of cyanobacteria, eukaryotic algae, fungi, lichens, and bryophytes embedded into the surface of desert soils, providing a protective buffer against the harsh desert environment. Our work focused on one type of desert BSC, the cyanolichen crust dominated by Collema sp. Using culture-dependent protocols, three MCFs were axenically isolated from their respective samples along with the extracted DNA. Their genomes were sequenced using Illumina and Nanopore, and finally assembled and annotated using hybrid assembly approaches and established bioinformatics pipelines to conduct final taxonomic phylogenetic analysis and placement. The three species described here are unique specimen from desert BSCs, here we introduce, Neophaeococcomyces mojavensis (Chaetothyriales), Cladosporium tulheliwenetii (Dothideales), and Taxawa tesnikishii (Dothideales).
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PURPOSE: Rare yeasts species are increasingly reported as causative agents of invasive human infection. Proper identification and antifungal therapy are essential to manage these infections. Candida blankii is one of these emerging pathogens and is known for its reduced susceptibility to multiple antifungals. METHODS: To obtain more insight into the characteristics of this species, 26 isolates reported as C. blankii were investigated using genetic and phenotypical approaches. RESULTS: Among the 26 isolates, seven recovered either from blood, sputum, urine, or the oral cavity, displayed substantial genetic and some phenotypical differences compared to the other isolates, which were confirmed as C. blankii. We consider these seven strains to represent a novel species, Tardiomyces depauwii. Phylogenomics assigned C. blankii, C. digboiensis, and the novel species in a distinct branch within the order Dipodascales, for which the novel genus Tardiomyces is erected. The new combinations Tardiomyces blankii and Tardiomyces digboiensis are introduced. Differences with related, strictly environmental genera Sugiyamaella, Crinitomyces, and Diddensiella are enumerated. All three Tardiomyces species share the rare ability to grow up to 42 °C, display slower growth in nutrient-poor media, and show a reduced susceptibility to azoles and echinocandins. Characteristics of T. depauwii include high MIC values with voriconazole and a unique protein pattern. CONCLUSION: We propose the novel yeast species Tardiomyces depauwii and the transfer of C. blankii and C. digboiensis to the novel Tardiomyces genus.
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The present paper includes a meta-analysis of literature data on 318 species of fungi belonging to 34 orders in their response to 8 antifungal agents (amphotericin B, caspofungin, fluconazole, itraconazole, ketoconazole, posaconazole, terbinafine, and voriconazole). Main trends of MIC results at the ordinal level were visualized. European Committee on Antimicrobial Susceptibility Testing and Clinical & Laboratory Standards Institute (CLSI) clinical breakpoints were used as the staff gauge to evaluate MIC values ranging from resistance to susceptibility, which were subsequently compared with a phylogenetic tree of the fungal kingdom. Several orders (Hypocreales, Microascales, and Mucorales) invariably showed resistance. Also the basidiomycetous orders Agaricales, Polyporales, Sporidiales, Tremellales, and Trichosporonales showed relatively high degrees of azole multi-resistance, while elsewhere in the fungal kingdom, including orders with numerous pathogenic and opportunistic species, that is, Onygenales, Chaetothyiales, Sordariales, and Malasseziales, in general were susceptible to azoles. In most cases, resistance vs susceptibility was consistently associated with phylogenetic distance, members of the same order showing similar behavior. IMPORTANCE: A kingdom-wide the largest set of published wild-type antifungal data comparison were analyzed. Trends in resistance in taxonomic groups (monophyletic clades) can be compared with the phylogeny of the fungal kingdom, eventual relationships between fungus-drug interaction and evolution can be described.
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Antifúngicos , Fluconazol , Humanos , Antifúngicos/farmacología , Filogenia , Pruebas de Sensibilidad Microbiana , Voriconazol , Azoles/farmacología , Farmacorresistencia FúngicaRESUMEN
BACKGROUND: Chromoblastomycosis is the World Health Organization (WHO)-recognized fungal implantation disease that eventually leads to severe mutilation. Cladophialophora carrionii (C. carrionii) is one of the agents. However, the pathogenesis of C. carrionii is not fully investigated yet. METHODS: We investigated the pathogenic potential of the fungus in a Galleria mellonella (G. mellonella) larvae infection model. Six strains of C. carrionii, and three of its environmental relative C. yegresii were tested. The G. mellonella model was also applied to determine antifungal efficacy of amphotericin B, itraconazole, voriconazole, posaconazole, and terbinafine. RESULTS: All strains were able to infect the larvae, but virulence potentials were strain-specific and showed no correlation with clinical background of the respective isolate. Survival of larvae also varied with infection dose, and with growth speed and melanization of the fungus. Posaconazole and voriconazole exhibited best activity against Cladophialophora, followed by itraconazole and terbinafine, while limited efficacy was seen for amphotericin B. CONCLUSION: Infection behavior deviates significantly between strains. In vitro antifungal susceptibility of tested strains only partly explained the limited treatment efficacy in vivo.
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Trichophyton species cause dermatophytosis in humans, with a high, worldwide frequency of reports and important public health relevance. We evaluated 61 Trichophyton strains from different sources deposited in the University Recife Mycology (URM) culture collection of the Universidade Federal de Pernambuco, Brazil. Strains were phenotypically identified and confirmed by sequencing Internal Transcribed Spacers rDNA and partial beta-tubulin 2-exon. Additionally, we evaluated their susceptibility to terbinafine and itraconazole. Physiological analyses included urease activity and growth in casein medium. Phenotypic methods allowed the reliable identification of T. rubrum only, whereas, for other species, molecular methods were mandatory. All Trichophyton species exhibited susceptibility profiles to itraconazole (0.04-5.33 µg/mL) and terbinafine (0.17-3.33 µg/mL). Our analyses revealed a heterogeneous distribution of T. mentagrophytes, which does not support the current distribution within the species complex of T. mentagrophytes and its genotypes.
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Arthrodermataceae , Tiña , Humanos , Trichophyton , Terbinafina/farmacología , Antifúngicos/farmacología , Itraconazol , Brasil , Universidades , Pruebas de Sensibilidad Microbiana , Arthrodermataceae/genéticaRESUMEN
The rapid pace of name changes of medically important fungi is creating challenges for clinical laboratories and clinicians involved in patient care. We describe two sources of name change which have different drivers, at the species versus the genus level. Some suggestions are made here to reduce the number of name changes. We urge taxonomists to provide diagnostic markers of taxonomic novelties. Given the instability of phylogenetic trees due to variable taxon sampling, we advocate to maintain genera at the largest possible size. Reporting of identified species in complexes or series should where possible comprise both the name of the overarching species and that of the molecular sibling, often cryptic species. Because the use of different names for the same species will be unavoidable for many years to come, an open access online database of the names of all medically important fungi, with proper nomenclatural designation and synonymy, is essential. We further recommend that while taxonomic discovery continues, the adaptation of new name changes by clinical laboratories and clinicians be reviewed routinely by a standing committee for validation and stability over time, with reference to an open access database, wherein reasons for changes are listed in a transparent way.
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Hongos , Humanos , Filogenia , Bases de Datos Factuales , Hongos/genéticaRESUMEN
Sugarcane (Saccharum officinarum, Poaceae) is cultivated on a large scale in (sub)tropical regions such as Brazil and has considerable economic value for sugar and biofuel production. The plant is a rich substrate for endo- and epiphytic fungi. Black yeasts in the family Herpotrichiellaceae (Chaetothyriales) are colonizers of human-dominated habitats, particularly those rich in toxins and hydrocarbon pollutants, and may cause severe infections in susceptible human hosts. The present study assessed the diversity of Herpotrichiellaceae associated with sugarcane, using in silico identification and selective isolation. Using metagenomics, we identified 5833 fungal sequences, while 639 black yeast-like isolates were recovered in vitro. In both strategies, the latter fungi were identified as members of the genera Cladophialophora, Exophiala, and Rhinocladiella (Herpotrichiellaceae), Cyphellophora (Cyphellophoraceae), and Knufia (Trichomeriaceae). In addition, we discovered new species of Cladophialophora and Exophiala from sugarcane and its rhizosphere. The first environmental isolation of Cladophialophora bantiana is particularly noteworthy, because this species up to now is exclusively known from the human host where it mostly causes fatal brain disease in otherwise healthy patients.
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Fungal rhinosinusitis (FRS) is a common problem worldwide, with an increasing burden in arid climate regions. Aspergillus species are the most common causative agents involved. In the present study, we investigated the prevalence, molecular characterization, and antifungal susceptibility of opportunists causing FRS in Sudan on the basis of strains collected over a period of 5 years. ß-Tubulin and calmodulin sequencing were used for species identification, and antifungal susceptibility profiles were evaluated by the protocol of the European Committee on Antimicrobial Susceptibility Testing (EUCAST). Predominant species belonged to the Aspergillus flavus complex (n = 244), A. terreus complex (n = 16), A. fumigatus complex (n = 7), and other fungi (n = 17). Molecular identification of 94 strains of Aspergillus revealed the following species: A. flavus (n = 88), A. terreus (n = 1), A. citrinoterreus (n = 2), A. fumigatus (n = 1), A. caespitosus (n = 1), and A. sydowii (n = 1). Several A. flavus and an A. fumigatus isolates showed reduced susceptibility to azoles (minimum inhibitory concentrations above the clinical breakpoints or epidemiological cutoff values). Despite several mutations revealed in cyp51A of these isolates, none could be directly linked to azole resistance. Molecular identification of fungi causing FRS is useful to identify cryptic species and for epidemiologic studies. IMPORTANCE Fungal rhinosinusitis (FRS) is a significant clinical problem in arid regions. This study provides new insights into the prevalence, etiology, and antifungal susceptibility of FRS pathogens in Sudan, where the disease burden is high. Aspergillus species, particularly the A. flavus complex, were identified as the primary FRS pathogens in the region, with some evidence of antifungal resistance. The molecular identification of fungal species causing FRS is useful for detecting antifungal resistance, identifying cryptic species, and characterizing the epidemiology of the disease. The emergence of Azole resistance Aspergilli in Sudan highlights the need for continued surveillance and appropriate use of antifungal agents. These findings have important implications for clinical management, public health policy, and future research on FRS. Publishing this study in Microbiology Spectrum would enable other researchers and clinicians to build on these findings, ultimately improving the diagnosis, treatment, and prevention of FRS.
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BACKGROUND: Trichophyton indotineae, a new species of dermatophytes, has become a significant concern in treating dermatophytosis due to the high level of terbinafine resistance reported in India and even worldwide. OBJECTIVES: This study aimed to report the terbinafine- and itraconazole-resistant T. indotineae in Chinese mainland, by identifying the phylogenetic classification of the isolate strain, and detecting the drug resistance, gene mutation and expression. PATIENTS/METHODS: The skin scales of the patient were cultured on SDA and the isolate was authenticated by DNA sequencing and MALDI-TOF MS. Antifungal susceptibility testing was performed following the M38-A2 CLSI protocol to examine the MICs values of terbinafine, itraconazole, fluconazole, etc. The strain was screened for mutations in the squalene epoxidase (SQLE) gene by Sanger sequencing and detected the expression of CYP51A and CYP51B by qRT-PCR. RESULTS: A multi-resistant ITS genotype VIII sibling of the T. mentagrophytes complex (T. indotineae) was isolated in Chinese mainland. The strain harbored high terbinafine MIC of > 32 µg/mL and itraconazole MIC of 1.0 µg/mL, which was identified a mutation in the squalene epoxidase gene with amino acid substitution (Phe397Leu, mutation 1191C > A). In addition, overexpression of CYP51A and CYP51B was observed. With multiple relapses, the patient finally achieved clinical cure by itraconazole pulse therapy and topical clotrimazole cream for 5 weeks. CONCLUSIONS: The first domestic strain of terbinafine- and itraconazole-resistant T. indotineae from a patient in Chinese mainland was isolated. Itraconazole pulse therapy can be an effective method for the treatment of T. indotineae.
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Farmacorresistencia Fúngica , Itraconazol , Terbinafina , Trichophyton , Humanos , Antifúngicos/farmacología , Farmacorresistencia Fúngica/genética , Itraconazol/farmacología , Pruebas de Sensibilidad Microbiana , Filogenia , Escualeno-Monooxigenasa/genética , Terbinafina/farmacología , Trichophyton/efectos de los fármacos , Trichophyton/genéticaRESUMEN
Dermatophytic pseudomycetoma is a rare invasive infection, involving both immunocompetent and immunocompromised individuals. Since the discovery of inherited immune disorders such as the impairment of CARD9 gene, extended dermatophyte infections are mostly ascribed to any of these host factors. This study is to present and explore the potential causes in a fatal dermatophytic pseudomycetoma patient. We present a chronic and deep pseudomycetoma caused by the common dermatophyte Microsporum canis which ultimately led to the death of the patient. Mycological examination, genetic studies and host immune responses against fungi were performed to explore the potential factors. The patient had decreased lymphocyte counts with significantly reduced CD4+ T cells, although all currently known genetic parameters proved to be normal. Through functional studies, we demonstrated that peripheral blood mononuclear cells from the patient showed severe impairment of adaptive cytokine production upon fungus-specific stimulation, whereas innate immune responses were partially defective. This is, to our knowledge, the first report of fatal dermatophytic pseudomycetoma in a patient with non-HIV CD4 lymphocytopenia, which highlights the importance of screening for immune deficiencies in patients with deep dermatophytosis.
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Dermatomicosis , Microsporum , Enfermedades Raras , Humanos , Dermatomicosis/genética , Dermatomicosis/inmunología , Dermatomicosis/microbiología , Micetoma/genética , Micetoma/inmunología , Micetoma/microbiología , Femenino , Persona de Mediana Edad , Microsporum/aislamiento & purificación , Resultado Fatal , Caspasa 9/genética , Receptores de Interleucina-7/genética , Mutación , Enfermedades Raras/genética , Enfermedades Raras/inmunología , Enfermedades Raras/microbiología , Recuento de Linfocito CD4 , Inmunidad InnataRESUMEN
Paracoccidioides species have always been surrounded by taxonomic uncertainties. The continuing nomenclatoral muddle was caused in part by the failure of Adolfo Lutz and Jorge Lôbo to name the etiologic agents of human paracoccidioidomycosis and Jorge Lôbo's diseases, respectively. Early in their history, it was postulated that the cultivable species causing systemic infections belonged in the genus Paracoccidioides, whereas the uncultivable species, causing skin disease, were not part of the genus. The taxonomy of these pathogens was further complicated when a similar skin disease with numerous yeast-like cells in infected dolphins was also reported. Due to its phenotypic similarities with that described by Jorge Lôbo in human and its uncultivable nature, it was assumed that the disease in dolphins was caused by the same fungus. Recent molecular and population genetic analysis, however, found the DNA extracted from the uncultivable yeast-like cells affecting dolphins shared common phylogenetic traits with cultivable Paracoccidioides species. The study revealed that the uncultivable pathogens comprised 2 different Paracoccidioides species, now known as P. ceti and P. loboi, correspondingly. To validate P. loboi binomial, a comprehensive historical critical review of Jorge Lôbo etiology was performed. This review showed the proposed binomial P. loboi was previously used, and, thus, a replacement name is introduced, Paracoccidioides lobogeorgii nom. nov. In addition, in this review, several cultivable human Paracoccidioides species are validated, and the generic type species, P. brasiliensis, is neotypified as the original material could not be traced.
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Delfines , Paracoccidioides , Paracoccidioidomicosis , Humanos , Animales , Paracoccidioides/genética , Filogenia , Saccharomyces cerevisiae , Paracoccidioidomicosis/epidemiología , Paracoccidioidomicosis/veterinaria , Paracoccidioidomicosis/microbiologíaRESUMEN
Fungal infections of the skin, nails, and hair caused by dermatophyte species continue to be a worldwide concern. The increase in terbinafine-resistant superficial dermatophytosis has become a major concern over the last decade. In this report, we presented two cases of infection with terbinafine-resistant Trichophyton indotineae, the first diagnosis of this species in Turkey. One patient exhibited erythematous pruritic patches and plaques in the inguinal and gluteal regions, while the other patient showed annular erythematous scaly plaques in the bilateral posterior thigh and gluteal regions. One patient harbored a CD36 mutation. Both strains harbored the same amino acid substitution in the squalene epoxidase gene, whereas one isolate had another unknown mutation. Clinical improvement was observed with resveratrol treatment in the patient with the CD36 mutation but not in the other patient.
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Antifúngicos , Farmacorresistencia Fúngica , Terbinafina , Trichophyton , Humanos , Antifúngicos/farmacología , Antifúngicos/uso terapéutico , Farmacorresistencia Fúngica/genética , Pruebas de Sensibilidad Microbiana , Mutación , Terbinafina/farmacología , Terbinafina/uso terapéutico , Trichophyton/efectos de los fármacos , Trichophyton/genética , TurquíaRESUMEN
Mycetoma is a chronic infectious disease endemic in sub-Saharan Africa (SSA), India and parts of South and North America. The epidemiologic profile of the disease in Egypt, which neighbours SSA, has not been explored previously. Therefore we conducted a scoping review of the literature on mycetoma in Egypt. We searched the literature comprehensively on MEDLINE and Google Scholar using free-text words and Medical Subject Headings and terms. Both published and non-peer-reviewed (grey literature) articles were included. The initial search identified 133 reports. Of these, only eight were found to be relevant and were included in the study. The total number of mycetoma patients was 59, reported between 1949 and 2015. There was a predilection for eumycetoma (44 of 59) patients (75%), while actinomycetoma constituted 15 patients (25%). Six patients were female, 28 were male and 25 were unreported. Children and adolescents constituted 3 of 59 (5%), 52 (88%) were adults and age was not provided for 4 patients. Only four patients (7%) were non-autochthonous. The incidence of mycetoma in Egypt is higher than previously reported. Egypt is probably a low-endemic country. An accurate estimate of the prevalence and epidemiology of mycetoma necessitates further research collaboration.
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Micetoma , Adulto , Niño , Adolescente , Humanos , Masculino , Femenino , Micetoma/epidemiología , Egipto/epidemiología , Incidencia , IndiaRESUMEN
BACKGROUND: Tinea capitis, atopic dermatitis and allergic rhinitis are the most common disorders endured by prepubescent children. Dermatophyte infections have been linked to allergic disorders, such as increased sensitivity to dermatophytes in patients with atopic dermatitis. OBJECTIVES: To explore the correlation between tinea capitis and allergic diseases in children and to analyse their risk factors. METHODS: This study monitored epidemiological changes in childhood tinea capitis and risk factors for whom with allergic disease in a single centre in three consecutive five-year intervals by reviewing clinical data and multivariate logistic data analysis. RESULTS: Between 2007 and 2022, there were 127 children patients with tinea capitis, the mean age was 4.83 years, and the male-to-female ratio was 1.76:1. Zoophilic Microsporum canis and Trichophyton mentagrophytes were the most prevalent pathogens, and the proportions remained relatively constant every 5 years. There were 34 (26.8%) children with tinea capitis complicated with allergic disease, among them 14 children with atopic dermatitis/eczema, 13 with allergic rhinitis, 8 urticaria, 6 food allergies and 1 allergic asthma. Male, kerion, zoophilic species infections and animal contact history were prevalent features in allergic disease combined with tinea capitis. Patients with tinea capitis plus allergic disease mostly had a family history with similar complications. CONCLUSION: M. canis and T. mentagrophytes were the most prevalent pathogens of tinea capitis in the last 15 years; atopic dermatitis/eczema and allergic rhinitis were the most frequently associated allergic diseases. Male, kerion, zoophilic pathogen and animal contact history are risk factors.
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Dermatitis Atópica , Eccema , Rinitis Alérgica , Tiña del Cuero Cabelludo , Animales , Masculino , Femenino , Tiña del Cuero Cabelludo/epidemiología , Microsporum , Factores de Riesgo , TrichophytonRESUMEN
Actinomortierella wolfii (Mortierellales), formerly Mortierella wolfii, is a causative agent of bovine systemic infection and abortion. Human infections caused by this species are extremely rare. Here, we present a case of a patient with B-Cell Acute Lymphoblastic Leukemia (B-ALL) who was diagnosed with a rhinocerebral infection caused by this fungus. Amphotericin treatment of the patient proved unsuccessful. This type of disease is otherwise nearly exclusively limited to members of the order Mucorales. The taxonomy of the causative agent is discussed.
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Fungi are an understudied resource possessing huge potential for developing products that can greatly improve human well-being. In the current paper, we highlight some important discoveries and developments in applied mycology and interdisciplinary Life Science research. These examples concern recently introduced drugs for the treatment of infections and neurological diseases; application of -OMICS techniques and genetic tools in medical mycology and the regulation of mycotoxin production; as well as some highlights of mushroom cultivaton in Asia. Examples for new diagnostic tools in medical mycology and the exploitation of new candidates for therapeutic drugs, are also given. In addition, two entries illustrating the latest developments in the use of fungi for biodegradation and fungal biomaterial production are provided. Some other areas where there have been and/or will be significant developments are also included. It is our hope that this paper will help realise the importance of fungi as a potential industrial resource and see the next two decades bring forward many new fungal and fungus-derived products.