Assuntos
Piedra , Trichosporon , Humanos , Trichosporon/isolamento & purificação , Trichosporon/classificação , Trichosporon/genética , Piedra/microbiologia , Piedra/diagnóstico , Piedra/patologia , Tricosporonose/microbiologia , Tricosporonose/diagnóstico , Tricosporonose/tratamento farmacológico , MasculinoRESUMO
Mucormycosis is a rare life-threatening opportunistic infection, with rhinocerebral mucormycosis (ROCM) being the most common presentation. Trichosporon asahii is an emerging pathogen that often causes fatal infections in patients with underlying hematologic malignancies due to its high drug resistance. We report a rare case of concomitant rhinocerebral mucormycosis and T. asahii fungemia secondary to Pseudomonas aeruginosa sepsis in a patient with neutropenia and acute lymphoblastic leukemia. A boy aged one year and two months was diagnosed with B-cell acute lymphoblastic leukemia on January 10 and underwent three courses of regular chemotherapy. He experienced neutropenia for 154 days and was hospitalized for vomiting, diarrhea and fever for 3 days. The day after hospitalization, Pseudomonas aeruginosa was isolated by blood culture and ceftazidime/avibactam was administered. Extracorporeal Membrane Oxygenation (ECMO) was used to provide continuous extracorporeal respiration and circulation for the patient. On day 8, the patient developed T. asahii fungemia. On day 10, he presented with necrotizing skin caused by Rhizopus delemar. He was treated with liposomal amphotericin B for Rhizopus delemar and voriconazole for T. asahii infection. Unfortunately, his health deteriorated and he died on day 11 due to the rapid progression of the infection and multiple organ failure. The management and treatment of such a complex infection requires a multidisciplinary approach and close monitoring of the patient's condition. Therefore, it is imperative to continue to research and report rare cases such as this to further understand the complexities of mucormycosis and trichosporidiosis coinfection and improve patient outcomes.
Assuntos
Coinfecção , Fungemia , Mucormicose , Leucemia-Linfoma Linfoblástico de Células Precursoras , Tricosporonose , Humanos , Masculino , Mucormicose/complicações , Mucormicose/diagnóstico , Leucemia-Linfoma Linfoblástico de Células Precursoras/complicações , Fungemia/microbiologia , Fungemia/tratamento farmacológico , Evolução Fatal , Coinfecção/microbiologia , Tricosporonose/microbiologia , Tricosporonose/diagnóstico , Tricosporonose/tratamento farmacológico , Lactente , Infecções Oportunistas/microbiologia , Infecções Oportunistas/complicações , Infecções por Pseudomonas/tratamento farmacológico , Infecções por Pseudomonas/microbiologia , Infecções por Pseudomonas/complicações , Antifúngicos/uso terapêutico , BasidiomycotaRESUMO
During an epidemiological survey, a potential novel species within the basidiomycetous yeast genus Trichosporon was observed. The clinical strain was obtained from a urine sample taken from a Brazilian kidney transplant recipient. The strain was molecularly identified using the intergenic spacer (IGS1) ribosomal DNA locus and a subsequent phylogenetic analysis showed that multiple strains that were previously reported by other studies shared an identical IGS1-genotype most closely related to that of Trichosporon inkin. However, none of these studies provided an in-depth characterization of the involved strains to describe it as a new taxon. Here, we present the novel clinically relevant yeast for which we propose the name Trichosporon austroamericanum sp. nov. (holotype CBS H-24937). T. austroamericanum can be distinguished from other siblings in the genus Trichosporon using morphological, physiological, and phylogenetic characters.
Assuntos
DNA Fúngico , DNA Espaçador Ribossômico , Filogenia , Análise de Sequência de DNA , Transplantados , Trichosporon , Tricosporonose , Trichosporon/classificação , Trichosporon/genética , Trichosporon/isolamento & purificação , DNA Espaçador Ribossômico/genética , DNA Espaçador Ribossômico/química , DNA Fúngico/genética , Humanos , Brasil , Tricosporonose/microbiologia , Análise por Conglomerados , Técnicas de Tipagem Micológica , Transplante de Rim , Microscopia , GenótipoRESUMO
Trichosporon spp. is an emerging opportunistic pathogen and a common cause of both superficial and invasive infections. Although Trichosporon asahii is the most frequently isolated species, Trichosporon cutaneum is also widely observed, as it is the predominant agent in cases of white Piedra and onychomycosis. Trichosporon spp. is a known to produce biofilms, which serve as one of its virulence mechanisms, however, there is limited data available on biofilms formed by T. cutaneum. Thus, the aim of this study was to assess the adhesion and biofilm formation of two clinical isolates of T. cutaneum under various environmental conditions (including temperature, nutrient availability, and carbon source), as well as their tolerance to fluconazole. Adhesion was tested on common abiotic substrates (such as silicone, glass, and stainless steel), revealing that T. cutaneum readily adhered to all surfaces tested. CV staining was applied for the evaluation of the environment influence on biofilm efficiency and it was proved that the nutrient availability has a major impact. Additionaly, fluorescent staining was employed to visualize the morphology of T. cutaneum biofilm and its survival in the presence of fluconazole. Hyphae production was shown to play a role in elevated biofilm production in minimal medium and increased tolerance to fluconazole.
Assuntos
Biofilmes , Trichosporon , Biofilmes/crescimento & desenvolvimento , Trichosporon/fisiologia , Trichosporon/isolamento & purificação , Trichosporon/efeitos dos fármacos , Humanos , Tricosporonose/microbiologia , Antifúngicos/farmacologia , Fluconazol/farmacologiaRESUMO
Onychomycosis, a fungal infection affecting the nail, is characterized by discoloration and thickening of the nail plate and is the most prevalent nail infection globally. We present a case of onychomycosis caused by Trichosporon asahii, a less common etiology. Notably, the patient was successfully treated with a non-traditional antibacterial approach, photodynamic therapy, which has been infrequently documented in the literature for such infections.
Assuntos
Ácido Aminolevulínico , Onicomicose , Fotoquimioterapia , Fármacos Fotossensibilizantes , Humanos , Onicomicose/tratamento farmacológico , Onicomicose/microbiologia , Fotoquimioterapia/métodos , Fármacos Fotossensibilizantes/uso terapêutico , Ácido Aminolevulínico/uso terapêutico , Masculino , Trichosporon , Tricosporonose/tratamento farmacológico , Pessoa de Meia-Idade , Feminino , BasidiomycotaRESUMO
Disseminated trichosporonosis is a rare fungal infection whose risk factors are hematological malignancies and neutropenia. Recently, breakthrough Trichosporon infections after administration of micafungin, the first-line systemic antifungal agent in compromised hosts, have been widely recognized. A man in his seventies about 1 month into chemotherapy for acute megakaryoblastic leukemia presented with a worsening fever and dyspnea. The patient was being administered with empirical micafungin therapy for suspected candidiasis. As the symptoms progressed, scattered erythema appeared on the trunk, some with a dark red vesicle at the center. Blood cultures identified Trichosporon asahii, as did the specimen of the skin biopsy. On the basis also of the presence of pneumonia on chest computed tomography, we confirmed the diagnosis of disseminated trichosporonosis and changed the antifungal agent from micafungin to voriconazole. Blood culture turned out to be negative 1 month after administrating voriconazole. However, the patient died of the leukemia. Our review of previous reports on cutaneous manifestations of disseminated trichosporonosis revealed that despite their morphological diversity, erythema with a red papule or vesicle at the center, implying necrosis, was also observed in previous cases. Our case report suggests that dermatologists should be aware of skin manifestations of disseminated trichosporonosis after micafungin administration, especially in cases of hematological malignancies.
Assuntos
Neoplasias Hematológicas , Leucemia Megacarioblástica Aguda , Trichosporon , Tricosporonose , Masculino , Humanos , Micafungina , Antifúngicos/uso terapêutico , Voriconazol , Tricosporonose/diagnóstico , Tricosporonose/tratamento farmacológico , Tricosporonose/microbiologia , Leucemia Megacarioblástica Aguda/complicações , Leucemia Megacarioblástica Aguda/tratamento farmacológico , Neoplasias Hematológicas/complicações , Neoplasias Hematológicas/tratamento farmacológico , Eritema/complicações , Eritema/tratamento farmacológicoRESUMO
Trichosporon asahii is a pathogenic yeast that cause trichosporonosis. T. asahii exhibits several colony morphologies, such as white (W)- or off-white (O)-type, which may affect virulence. In this study, we compared the expression pattern of heparin-binding proteins in various colony morphologies and identified heparin-binding protein in T. asahii. Surface plasmon resonance analysis revealed that cell surface molecules attached more strongly to heparin in W- than O-type cells. We purified and identified a heparin-binding protein strongly expressed in W-type cells using heparin-Sepharose beads, named it heparin-binding protein 1 (HepBP1), and expressed Flag-tagged HepBP1 in mammalian cells. The heparin-binding ability of Flag-tagged HepBP1 was confirmed by pulldown assay using heparin-Sepharose beads. Thus, HepBP1 is a heparin-binding protein on T. asahii cell surface. These results suggest that several T. asahii cell surface proteins interact with glycosaminoglycans; therefore, they could contribute to infection.
Assuntos
Heparina , Heparina/metabolismo , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Ligação Proteica , Proteínas de Membrana/genética , Proteínas de Membrana/metabolismo , Tricosporonose/microbiologia , Humanos , Ressonância de Plasmônio de Superfície , Proteínas de Transporte/genética , Proteínas de Transporte/metabolismo , Membrana Celular/metabolismo , BasidiomycotaRESUMO
ABSTRACT: The emergence of non-Candida yeast infections in humans has been increasingly recognized over the last decades. Trichosporon is the third most isolated non-candidal yeast in patients with an impaired immune system. We report a rare case of Trichosporon asahii causing erythematous oral lesion in a patient with squamous cell carcinoma. Our case highlights the occurrence of unusual yeast pathogens in patients with cancer with typical clinical presentations and warrants suspicion of fungal etiology to prevent misdiagnosis of trichosporonosis.
Assuntos
Carcinoma de Células Escamosas , Neoplasias Bucais , Tricosporonose , Humanos , Basidiomycota , Carcinoma de Células Escamosas/diagnóstico , Histocitoquímica , Microscopia , Neoplasias Bucais/patologia , Trichosporon/isolamento & purificação , Trichosporon/patogenicidade , Tricosporonose/diagnóstico , Tricosporonose/microbiologia , Tricosporonose/patologia , Tricosporonose/tratamento farmacológicoRESUMO
BACKGROUND: Summer-type hypersensitivity pneumonitis (SHP) has been reported to occur during warm and humid summer seasons in Japan; however, the effect of weather conditions on SHP remains unknown. Anti-Trichosporon asahii antibody (TaAb) test is highly specific and useful for the diagnosing SHP. Therefore, we aimed to investigate the impact of weather conditions on SHP by examining the relationship between the positivity rate of TaAb and warm and humid days. METHODS: TaAb test data from June 2013 to June 2020 were obtained from major commercial laboratories to determine the number of samples and positivity rate of TaAb by prefecture. Using the Japan Meteorological Agency database, we counted the warm and humid days (maximum temperature ≥25 °C and average humidity ≥80 %) for each prefecture. Negative binomial regression was employed to examine the relationship between the positivity rate of TaAb and the number of warm and humid days per month. RESULTS: A total of 79,211 samples and 7626 positive samples (9.6 %) were identified. We found that the number of warm and humid days, 1 or 2 months prior to testing for TaAb, was associated with the positivity rate of the test. An increase in the positivity rate by 1.6 % and 2.9 % was observed with every 1-day increase in warm and humid days 1 month and 2 months before the test, respectively. CONCLUSIONS: Our TaAb analysis revealed a significant increase in TaAb positivity 1 or 2 months after periods of warm and humid days.
Assuntos
Alveolite Alérgica Extrínseca , Basidiomycota , Tricosporonose , Humanos , Tricosporonose/diagnóstico , Alveolite Alérgica Extrínseca/diagnóstico , Anticorpos Antifúngicos/análise , Estações do Ano , AnticorposRESUMO
Trichosporon asahii is an emerging opportunistic fungus that mainly causes fatal disseminated trichosporonosis, especially in immunocompromised patients. T. asahii infection has been reported in Thailand, but few studies of this fungus have been published. Therefore, this study investigated the genetic diversity of 51 clinical strains of T. asahii from urine samples in Thailand. We sequenced and characterized the beta-1-tubulin (TUB1), copper-exporting ATPase (ATP), phosphate carrier protein (PHCP), and topoisomerase-1 (TOP1) genes. In addition, intergenic spacer 1 (IGS1) sequences from our previous studies were investigated. The numbers of haplotypes were 3, 3, 2, 2, and 2 for IGS1, TUB1, ATP, PHCP, and TOP1, respectively. The results suggested a relatively low level of genetic diversity among the strains. The findings illustrated that IGS1, TUB1, ATP, PHCP, and TOP1 can be collectively used as an alternative molecular typing tool for investigating the population diversity and structure of T. asahii.
Assuntos
Trichosporon , Tricosporonose , Humanos , Trichosporon/genética , Genótipo , DNA Fúngico/genética , Tricosporonose/microbiologia , Trifosfato de Adenosina , Antifúngicos/farmacologiaRESUMO
OBJECTIVES: Molecular genotyping of Trichosporon species using intergenic spacer region (IGS-1) sequencing and antifungal drug susceptibility testing of T. asahii clinical isolates from Indian patients. MATERIALS AND METHODS: Fifty-five Trichosporon strains were characterized using IGS-1 sequencing from 2006 to 2018 and tested against 5 antifungals using CLSI M27-A3 guidelines. RESULTS: In this study, broad-spectrum antibiotics with steroids, catheters, and ICU stays were major underlying risk factors. These cases were most commonly associated with diabetes (type-2), chronic obstructive pulmonary disease, and hypertension. Out of fifty-five isolates, 47 (85%) were identified as T. asahii, and the remaining 6 were T. inkin (11%) and 2 were Cutaneotrichosporon dermatis (3.6%). The most common genotype of T. asahii was G3 (22; 49%) subsequently G4 (12; 23%), G1 (8; 17%), and G7 (2; 4%). One new genotype of T asahii was found in addition to the fifteen already known genotypes. Indian T. asahii isolates showed a low level of amphotericin B (range 0.06-4 âmg/l) resistance but relatively higher in fluconazole (range 0.25-64 âmg/l). Although, comparatively low MIC ranges were found in the case of voriconazole (0.03-1 âmg/l), posaconazole (0.06-1 âmg/l) and itraconazole (0.06-1 âmg/l). Voriconazole appeared to be the most active drug in T. asahii isolates. The MICs for all the drugs were comparatively lower in the case of non-Trichosporon asahii strains. CONCLUSION: T. asahii was the most common Trichosporon isolate. Speciation is necessary for optimal antifungal therapy. Voriconazole-based treatment, Steroids, removal of catheters and control of underlying conditions results in positive outcomes.
Assuntos
Mycobacterium tuberculosis , Trichosporon , Tricosporonose , Humanos , Antifúngicos/farmacologia , Antifúngicos/uso terapêutico , Trichosporon/genética , Voriconazol/farmacologia , Voriconazol/uso terapêutico , DNA Intergênico/genética , Testes de Sensibilidade Microbiana , Mycobacterium tuberculosis/genética , Esteroides , Tricosporonose/tratamento farmacológicoRESUMO
BACKGROUND: The ATS/JRS/ALAT Guidelines for the Diagnosis of Hypersensitivity Pneumonitis (GL for HP) were published in 2020. Humidifier lung and summer-type HP are forms of HP, but it is unclear whether they can be diagnosed using GL for HP. This study examined the level of confidence where humidifier lung and summer-type HP can be diagnosed with GL for HP. METHODS: Data from 23 patients with humidifier lung and 20 patients with summer-type HP (mean age, 67.3 and 57.4 years, respectively) diagnosed between October 2012 and January 2022 were retrospectively reviewed. We evaluated high resolution computed tomography (HRCT) patterns, bronchoalveolar lavage fluid (BALF) findings, exposures, and histopathological findings to determine the level of confidence where a diagnosis of HP could be made using the GL for HP. RESULTS: HRCT pattern was classified as typical HP in 5 (22%) and compatible with HP in 18 (78%) patients with humidifier lung and considered as typical HP in 17 (85%) and compatible with HP in 3 (15%) patients with summer-type. The confidence level for diagnosis of HP was definite in 2 (8.7%), moderate in 14 (60.9%), and low in 7 (30.4%) patients with humidifier lung. It was definite in 12 (60%), high in 3 (15%), and moderate in 5 (25%) patients with summer-type HP. CONCLUSIONS: GL for HP showed utility in diagnosing humidifier lung in many patients with a moderate to low confidence. However, there was a definite to high confidence for patients with summer-type HP.
Assuntos
Alveolite Alérgica Extrínseca , Tricosporonose , Humanos , Tricosporonose/patologia , Umidificadores , Estudos Retrospectivos , Alveolite Alérgica Extrínseca/diagnóstico por imagem , Alveolite Alérgica Extrínseca/patologia , Pulmão/diagnóstico por imagem , Pulmão/patologiaRESUMO
BACKGROUND: Trichosporon is an emerging yeast that causes invasive infections in immunocompromised patients experiencing prolonged hospitalisation, indwelling venous catheters and neutropenia. METHODS: This retrospective observational cohort study analysed invasive Trichosporon infections (ITIs) occurring between January 2005 and December 2022 at three tertiary hospitals and compared the clinical characteristics and prognostic factors of ITIs caused by Trichosporon asahii and non-T. asahii spp. After evaluating 1067 clinical isolates, we identified 46 patients with proven ITIs, defined as cases in which Trichosporon was isolated from blood, cerebrospinal fluid, or sterile tissues. RESULTS: The patients were separated into T. asahii and non-T. asahii groups containing 25 and 21 patients, respectively, all of which except one were immunocompromised. During this period, both the number of clinical isolates and patients with ITIs (mainly T. asahii) increased; whereas, cases involving non-T. asahii spp. decreased. Compared with the non-T. asahii group, the T. asahii group had more patients with multiple catheters (84% vs. 33%, p = .001) and those receiving renal replacement therapy (48% vs. 14%, p = .005). The all-cause 28-day mortality rate after ITI in the T. asahii group (44%) was significantly higher than in the non-T. asahii group (10%, Log-rank p = .014). The multivariate Cox regression model revealed that T. asahii (reference, non-T. asahii spp.; aHR = 4.3; 95% CI = 1.2-15.2, p = .024) and neutropenia for 5 days or more (aHR = 2.2, 95% CI = 1.5-3.6, p = .035) were independent factors in the 28-day mortality after ITI. CONCLUSION: The proven ITIs due to T. asahii produced more unfavourable outcomes compared with ITIs caused by non-T. asahii spp.
Assuntos
Neutropenia , Trichosporon , Tricosporonose , Humanos , Tricosporonose/tratamento farmacológico , Antifúngicos/uso terapêutico , Estudos Retrospectivos , Neutropenia/tratamento farmacológicoRESUMO
Two adult mixed-breed ewes were presented with a 2-wk history of upper respiratory disease. Both animals were depressed, with bilateral serosanguineous nasal discharge and harsh bronchovesicular sounds accompanied by crackles and wheezes on auscultation. One animal was recumbent and was euthanized at presentation. The other animal with similar signs, as well as exophthalmos, was euthanized because of a mass in the nasal passages. On autopsy, severe pyogranulomatous and necrotizing ethmoidal rhinitis with focal pyogranulomatous pneumonia was diagnosed in both animals. An intralesional fungal organism was identified in the nares and lungs of both animals. The organism could not be isolated via fungal culture but was identified as Trichosporon sp. by a PCR assay. Trichosporon spp. are rarely associated with disease in veterinary medicine. This ubiquitous fungus might cause disease following trauma to the nasal passages or secondary to immunocompromise.
Assuntos
Pneumonia , Doenças dos Ovinos , Trichosporon , Tricosporonose , Feminino , Animais , Ovinos , Tricosporonose/diagnóstico , Tricosporonose/microbiologia , Tricosporonose/veterinária , Pulmão , Pneumonia/veterinária , Doenças dos Ovinos/diagnósticoRESUMO
La enfermedad fúngica invasora (EFI) es una de las principales causas de morbimortalidad en los pacientes pediátricos inmunocom- prometidos. Los hongos que con mayor frecuencia causan EFI en este grupo de pacientes corresponden a especies de Candida y Aspergillus. Sin embargo, en los últimos años se ha descrito un aumento de patógenos no clásicos, tales como Fusarium, Scedosporium, Mucorales, Cryptococcus, Trichosporon, entre otros. Se presenta un caso de EFI por Trichosporon asahii en un preescolar con una leucemia linfo- blástica aguda en quimioterapia de inducción. Además, se presenta una revisión actualizada de la literatura especializada, con énfasis en la importancia del diagnóstico precoz y el tratamiento antifúngico específico.
Invasive fungal disease (IFD) is one of the leading causes of morbidity and death among immunosuppressed pediatric patients. The fungi that most frequently cause IFD in this group of patients correspond to Candida and Aspergillus species, however, in recent years an increase in non-classical pathogens, such as Fusarium, Scedosporium, Mucorales, Cryptococcus, Trichosporon, among others. A case of invasive fungal disease caused by Trichosporon asahii is presented in a preschool patient with acute lymphoblastic leukemia in induction stage. This review highlights the importance of active search for pathogens in immunosuppressed patients, and proposes a specific treatment.
Assuntos
Humanos , Masculino , Pré-Escolar , Leucemia-Linfoma Linfoblástico de Células Precursoras/complicações , Tricosporonose/complicações , Infecções Fúngicas Invasivas , Trichosporon/isolamento & purificação , Tricosporonose/diagnóstico , Tricosporonose/microbiologia , Tricosporonose/tratamento farmacológico , Antifúngicos/uso terapêuticoRESUMO
Trichosporon asahii is an emerging opportunistic pathogen that causes potentially fatal disseminated trichosporonosis. The global prevalence of coronavirus disease 2019 (COVID-19) poses an increasing fungal infection burden caused by T. asahii. Allicin is the main biologically active component with broad-spectrum antimicrobial activity in garlic. In this study, we performed an in-depth analysis of the antifungal characteristics of allicin against T. asahii based on physiological, cytological, and transcriptomic assessments. In vitro, allicin inhibited the growth of T. asahii planktonic cells and biofilm cells significantly. In vivo, allicin improved the mean survival time of mice with systemic trichosporonosis and reduced tissue fungal burden. Electron microscopy observations clearly demonstrated damage to T. asahii cell morphology and ultrastructure caused by allicin. Furthermore, allicin increased intracellular reactive oxygen species (ROS) accumulation, leading to oxidative stress damage in T. asahii cells. Transcriptome analysis showed that allicin treatment disturbed the biosynthesis of cell membrane and cell wall, glucose catabolism, and oxidative stress. The overexpression of multiple antioxidant enzymes and transporters may also place an additional burden on cells, causing them to collapse. Our findings shed new light on the potential of allicin as an alternative treatment strategy for trichosporonosis. IMPORTANCE Systemic infection caused by T. asahii has recently been recognized as an important cause of mortality in hospitalized COVID-19 patients. Invasive trichosporonosis remains a significant challenge for clinicians, due to the limited therapeutic options. The present work suggests that allicin holds great potential as a therapeutic candidate for T. asahii infection. Allicin demonstrated potent in vitro antifungal activity and potential in vivo protective effects. In addition, transcriptome sequencing provided valuable insights into the antifungal effects of allicin.
Assuntos
COVID-19 , Trichosporon , Tricosporonose , Animais , Camundongos , Antifúngicos/farmacologia , Antifúngicos/uso terapêutico , Tricosporonose/tratamento farmacológico , Tricosporonose/microbiologia , Trichosporon/fisiologia , Antioxidantes/farmacologia , Antioxidantes/uso terapêuticoRESUMO
Trichosporon asahii is an invasive pathogenic yeast that infects immunocompromised hosts. Several virulence factors contribute to the fungal infection; however, the factors that contribute to the occurrence of T. asahii infections remain unclear. Since adhesins are typical virulence factors reported for pathogenic fungi, we looked for host proteins that interact with the T. asahii cell surface. T. asahii and Candida albicans were used for screening using a pull-down assay with fetal bovine serum. Serum albumin and elongation factor 2 were identified as the yeast-binding serum proteins. Additionally, we investigated the interactions of the cell surface-associated molecules (CSM) of T. asahii with vitronectin (VTN), fibronectin, fetuin-A, and alpha-1antitrypsin (AAT). The surface plasmon resonance (SPR) method was used to examine the interaction between CSM and human proteins. On the other hand, the pull-down assay was used to examine the interaction between human proteins and the T. asahii cell surface. Serum albumin, AAT, and VTN were found to interact with T. asahii in both SPR and pull-down assays. This study identified several proteins that interact with T. asahii, suggesting that these proteins play a role in infection mechanisms.
Assuntos
Basidiomycota , Trichosporon , Tricosporonose , Humanos , Proteínas Fúngicas , Albumina Sérica , Fatores de Virulência , Antifúngicos , Tricosporonose/microbiologiaRESUMO
Fungal dimorphism involves two morphologies: a unicellular yeast cell and a multicellular hyphal form. Invasion of hyphae into human cells causes severe opportunistic infections. The transition between yeast and hyphal forms is associated with the virulence of fungi; however, the mechanism is poorly understood. Therefore, we aimed to identify factors that induce hyphal growth of Trichosporon asahii, a dimorphic basidiomycete that causes trichosporonosis. T. asahii showed poor growth and formed small cells containing large lipid droplets and fragmented mitochondria when cultivated for 16 h in a nutrient-deficient liquid medium. However, these phenotypes were suppressed via the addition of yeast nitrogen base. When T. asahii cells were cultivated in the presence of different compounds present in the yeast nitrogen base, we found that magnesium sulfate was a key factor for inducing cell elongation, and its addition dramatically restored hyphal growth in T. asahii. In T. asahii hyphae, vacuoles were enlarged, the size of lipid droplets was decreased, and mitochondria were distributed throughout the cell cytoplasm and adjacent to the cell walls. Additionally, hyphal growth was disrupted due to treatment with an actin inhibitor. The actin inhibitor latrunculin A disrupted the mitochondrial distribution even in hyphal cells. Furthermore, magnesium sulfate treatment accelerated hyphal growth in T. asahii for 72 h when the cells were cultivated in a nutrient-deficient liquid medium. Collectively, our results suggest that an increase in magnesium levels triggers the transition from the yeast to hyphal form in T. asahii. These findings will support studies on the pathogenesis of fungi and aid in developing treatments. IMPORTANCE Understanding the mechanism underlying fungal dimorphism is crucial to discern its invasion into human cells. Invasion is caused by the hyphal form rather than the yeast form; therefore, it is important to understand the mechanism of transition from the yeast to hyphal form. To study the transition mechanism, we utilized Trichosporon asahii, a dimorphic basidiomycete that causes severe trichosporonosis since there are fewer studies on T. asahii than on ascomycetes. This study suggests that an increase in Mg2+, the most abundant mineral in living cells, triggers growth of filamentous hyphae and increases the distribution of mitochondria throughout the cell cytoplasm and adjacent to the cell walls in T. asahii. Understanding the mechanism of hyphal growth triggered by Mg2+ increase will provide a model system to explore fungal pathogenicity in the future.
Assuntos
Basidiomycota , Trichosporon , Tricosporonose , Humanos , Trichosporon/genética , Magnésio , Saccharomyces cerevisiae , Tricosporonose/microbiologia , Sulfato de Magnésio , Actinas , Nitrogênio , Antifúngicos/farmacologiaRESUMO
Trichosporon asteroides is an emerging yeast-like pathogen commonly misidentified by commercial biochemical identification systems. We evaluated the performance of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry for the identification of 21 clinical T. asteroides strains using the Bruker Daltonics database (BDAL) and an in-house developed library. Mass spectra were obtained by the FlexControl system v.3.4, and characterizations were performed in the Biotyper BDAL database v.4.1 and the developed in-house library. Species identification for T. asteroides failed as all 21 strains were misidentified as T. japonicum (log-scores 1.89-2.19). Extending the existing database was crucial to achieving 100% correct species-level identification and accurate distinction between species. Our results indicate that the commercial BDAL database has no discriminatory power to distinguish between T. japonicum and T. asteroides. Whereas improvement of the current BDAL database is pending, we strongly advise system users not to exclude the possibility of the failure to report T. asteroides.