Unveiling Trichosporon austroamericanum sp. nov.: A Novel Emerging Opportunistic Basidiomycetous Yeast Species.

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.

Adhesion and biofilm formation by two clinical isolates of Trichosporon Cutaneum in various environmental conditions.

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.

Photodynamic therapy successfully treats refractory onychomycosis caused by Trichosporon asahii: a case report.

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.

Erythematous ulcero-proliferative exophytic lesion in an oral squamous cell carcinoma patient- An unusual case of Trichosporonosis.

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.

Skin Manifestations of Micafungin Breakthrough Disseminated Trichosporonosis in Acute Megakaryoblastic Leukemia.

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.

Review Article White Piedra: Review of 131 cases.

This study analyzes the clinical characteristics of patients diagnosed with White Piedra through a systematic review of cases in the literature. A sample of 131 subjects was considered, of which 91.6% were female and most were 18 years of age or younger. Most studies were conducted in Brazil, followed by India, and Mexico. The most common etiologic agent found was Trichosporon spp (34.3%). Most affected patients were asymptomatic (94.6%) and predisposing factors included long hair, use of a hair band or hair accessories, and wet hair. The most common clinical feature was the presence of nodules. The evaluation of treatment effectiveness was hindered by the scarcity of follow-up information in the majority of the studies. It is concluded that White Piedra infection is more common in young women and is associated with hair-related factors.

The first report of Apiotrichum mycotoxinivorans isolation from human cerebrospinal fluid.

Fungal infections due to Apiotrichum mycotoxinivorans are clinically rare. Here, we report a case of invasive blood and cerebrospinal fluid infection by Apiotrichum mycotoxinivorans in a girl with B-cell acute lymphoblastic leukemia. This is the first report of the isolation of Apiotrichum mycotoxinivorans from human cerebrospinal fluid. MRI features of meningitis caused by this fungus are presented. Three small isoquinoline alkaloids inhibited the growth of this rare fungus in vitro, providing a starting point for the application of natural products to treat this highly fatal fungal infection. Our case presentation confirms Apiotrichum mycotoxinivorans as a potential emerging pathogen in patients with hematological malignancy undergoing chemotherapy.

Genetic analysis of emerging fungal pathogens: Trichosporon asahii.

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.

Intergenic spacer (IGS-1) region sequence-based identification, genotypic analysis, and antifungal susceptibility of clinical Trichosporon species.

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 â€‹mg/l) resistance but relatively higher in fluconazole (range 0.25-64 â€‹mg/l). Although, comparatively low MIC ranges were found in the case of voriconazole (0.03-1 â€‹mg/l), posaconazole (0.06-1 â€‹mg/l) and itraconazole (0.06-1 â€‹mg/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.

Differences of clinical characteristics and outcome in proven invasive Trichosporon infections caused by asahii and non-asahii species.

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.

Coproduction of single cell protein and lipid from lignocellulose derived carbohydrates and inorganic ammonia salt with soluble ammonia recycling.

Co-production of single cell protein (SCP) and lipid from lignocellulose-derived carbohydrates and inorganic ammonia offers a promising alternative for poultry or aquaculture feeds. An engineered oleaginous yeast Trichosporon cutaneum MP11 showed great potential for producing SCP and lipid from wheat straw and ammonia sulfate with minimum nutrient input. Trichosporon cutaneum MP11 showed stronger SCP and lipid fermentability using dry acid pretreated and biodetoxified wheat straw than using pure sugars. The residual ammonium sulfate in fermentation broth was recycled up to five times, resulting in ∼70% of nitrogen fixation into SCP. The overall yield of SCP and lipid from lignocellulose-derived sugars was 0.15 g/g and 0.11 g/g, respectively. This translates to the production of one ton of SCP (0.56 ton) and lipid (0.44 ton) from 6.6 tons of wheat straw, or one ton of SCP and lipid containing yeast cells (dry) from 4.8 tons of wheat straw.

Nasal trichosporonosis in 2 mixed-breed ewes.

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.

Infección invasora por Trichosporon asahii en un niño con leucemia linfoblástica aguda / Invasive fungal infection by Trichosporon asahii in a pediatric patient with acute lymphoblastic leukemia: A case report and review of the literature

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.

Cellulase mediated stress triggers the mutations of oleaginous yeast Trichosporon cutaneum with super-large spindle morphology and high lipid accumulation.

Accumulation of intracellular lipid bodies in oleaginous yeast cells is highly restricted by their natural intracellular space. Here we show a cellulase mediated adaptive evolution with ultra-centrifugation fractionation of oleaginous yeast Trichosporon cutaneum to obtain the favorable cell structure for lipid accumulation. Cellulase was added to the wheat straw hydrolysate during long-term adaptive evolution for disruption of cell wall integrity of T. cutaneum cells. The cellulase, together with ultracentrifugation force, triggered multiple mutations and transcriptional expression changes of the functional genes associated with cell wall integrity and lipid synthesis metabolism. The fractionated mutant T. cutaneum YY52 demonstrated the heavily weakened cell wall and high lipid accumulation by the super-large expanded spindle cells (two orders of magnitude greater than the parental). A record-high lipid production by T. cutaneum YY52 was achieved (55.4 ± 0.5 g L-1 from wheat straw and 58.4 ± 0.1 g L-1 from corn stover). This study not only obtained an oleaginous yeast strain with industrial application potential for lipid production but also provided a new method for generation of mutant cells with high intracellular metabolite accumulation.

Trichosporon asahii PLA2 Gene Enhances Drug Resistance to Azoles by Improving Drug Efflux and Biofilm Formation.

Trichosporon asahii is an opportunistic pathogen that can cause severe or even fatal infections in patients with low immune function. sPLA2 plays different roles in different fungi and is also related to fungal drug resistance. However, the mechanism underlying its drug resistance to azoles has not yet been reported in T. asahii. Therefore, we investigated the drug resistance of T. asahii PLA2 (TaPLA2) by constructing overexpressing mutant strains (TaPLA2OE). TaPLA2OE was generated by homologous recombination of the recombinant vector pEGFP-N1-TaPLA2, induced by the CMV promoter, with Agrobacterium tumefaciens. The structure of the protein was found to be typical of sPLA2, and it belongs to the phospholipase A2_3 superfamily. TaPLA2OE enhanced antifungal drug resistance by upregulating the expression of effector genes and increasing the number of arthrospores to promote biofilm formation. TaPLA2OE was highly sensitive to sodium dodecyl sulfate and Congo red, indicating impaired cell wall integrity due to downregulation of chitin synthesis or degradation genes, which can indirectly affect fungal resistance. In conclusion, TaPLA2 overexpression enhanced the resistance to azoles of T. asahii by enhancing drug efflux and biofilm formation and upregulating HOG-MAPK pathway genes; therefore, it has promising research prospects.

Antifungal Activity and Potential Action Mechanism of Allicin against Trichosporon asahii.

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.

Interaction of Host Proteins with Cell Surface Molecules of the Pathogenic Yeast Trichosporon asahii.

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.

Promethazine inhibits efflux, enhances antifungal susceptibility and disrupts biofilm structure and functioning in Trichosporon.

Trichosporon spp. are emerging opportunistic fungi associated with invasive infections, especially in patients with haematological malignancies. The present study investigated the in vitro inhibition of efflux pumps by promethazine (PMZ) as a strategy to control T. asahii and T. inkin. Planktonic cells were evaluated for antifungal susceptibility to PMZ, as well as inhibition of efflux. The effect of PMZ was also studied in Trichosporon biofilms. PMZ inhibited T. asahii and T. inkin planktonic cells at concentrations ranging from 32 to 256 µg ml-1. Subinhibitory concentrations of PMZ inhibited efflux activity in Trichosporon. Biofilms were completely eradicated by PMZ. PMZ potentiated the action of antifungals, affected the morphology, changed the amount of carbohydrates and proteins and reduced the amount of persister cells inside biofilms. The results showed indirect evidences of the occurrence of efflux pumps in Trichosporon and opens a perspective for the use of this target in the control of trichosporonosis.