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.

Identification of Clinical Trichosporon asteroides Strains by MALDI-TOF Mass Spectrometry: Evaluation of the Bruker Daltonics Commercial System and an In-House Developed Library.

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.

fuPCR as diagnostic method for the detection of rare fungal pathogens, such as Trichosporon, Cryptococcus and Fusarium.

Fungal respiratory tract colonization is a common finding in patients with hematologic neoplasms due to immunosuppression inherent in the diseases and exacerbated by therapy. This greatly increases the risk of fungal infections of the lungs, which is associated with significant mortality. Therefore, reliable diagnostic methods with rapidly available results are needed to administer adequate antifungal therapy. We have established an improved method for fungal DNA extraction and amplification that allows simultaneous detection of fungal families based on a set of multiplexed real-time PCR reactions (fuPCR). We analyzed respiratory rinses and blood of 94 patients with hematological systemic diseases by fuPCR and compared it with the results of culture and serological diagnostic methods. 40 healthy subjects served as controls. Regarding Candida species, the highest prevalence resulted from microbiological culture of respiratory rinses and from detection of antibodies in blood serum in patients (61 and 47%, respectively) and in the control group (29 and 51%, respectively). Detection of other pathogenic yeasts, such as Cryptococcus and Trichosporon, and molds, such as Fusarium, was only possible in patients by fuPCR from both respiratory rinses and whole blood and serum. These fungal species were found statistically significantly more frequent in respiratory rinses collected from patients after myeloablative therapy for stem cell transplantation compared to samples collected before treatment (P < 0.05i). The results show that fuPCR is a valuable complement to culturing and its inclusion in routine mycological diagnostics might be helpful for early detection of pathophysiologically relevant respiratory colonization for patients with hematologic neoplasms.

We validated a set of PCR reactions (fuPCR) for use in routine diagnostic. In contrast to culture and serological methods, only by fuPCR pathogenic yeasts (Cryptococcus and Trichosporon) and molds (Aspergillus and Fusarium) were detected in respiratory rinses and blood of hematological patients.

Prosthetic valve endocarditis by Trichosporon mucoides: A case report and review of literature.

NATIONALE: Trichosporon species are widely distributed in nature and are emerging opportunistic human pathogens. Trichosporon infections are associated with superficial cutaneous involvement in immunocompetent individuals to severe systemic disease in immunocompromised patients. Until now, there is no report in infective endocarditis by Trichosporon mucoides confirmed by molecular diagnostics PATIENT CONCERNS:: A 66-year-old man presented with a fever that had occurred for a period of 6 months. He had undergone aortic valve replacement 10 years prior. Transthoracic echocardiography showed vegetations on the prosthetic aortic valve and native mitral valve. T mucoides was detected in the cultures of blood and vegetations. DIAGNOSIS: DNA sequencing using D/D2 region of rRNA and internal transcribed spacer were performed. INTERVENTIONS: Infections were successfully controlled with valve replacement and voriconazole plus liposomal amphotericin B therapy. OUTCOMES: There has been no sign of recurrence for 18-months after treatment completion. LESSONS: This is the first reported case of infective endocarditis due to T mucoides. Clinicians should consider Trichosporon species as causative agents of endocarditis in patients who have undergone cardiac surgery.

Comparison of fungal and bacterial keratitis between tropical and subtropical Taiwan: a prospective cohort study.

BACKGROUND: Fungal keratitis (FK) has been shown to be a climate-sensitive disease. The differentiation between FK from bacterial keratitis (BK) was difficult. The purpose of this study was to compare the bacteriology and mycology between tropical and subtropical Taiwan and to investigate the independent risk factors for identification of fungi from bacteria. METHODS: Two hundred ninety-seven patients with clinical suspected microbial keratitis were prospectively enrolled. A fungal to bacteria rate (FBR), the number of fungi divided by bacteria identified, was determined to estimate the prevalence of fungi and bacteria. Clinical presentation, profiles of microorganisms, and predisposing risk factors were determined. Univariate and multivariate logistic regression analysis were used to investigate the independent risk factors. RESULTS: A total of 82 fungi and 143 bacteria were laboratory confirmed. The identification rate of fungus was higher in tropical Taiwan (p = 0.010). Among the fungi and bacteria confirmed, the FBR was 0.29 (22.4% vs. 77.6%) in subtropical Taiwan, and 0.70 (41.3% vs. 58.7%) in tropical Taiwan. Samples obtained in tropical area (p = 0.019), ocular trauma (p = 0.019), and plant exposure (p = 0.003) were independent risk factors for identification of fungus from bacteria. The predominant fungus isolated from corneal scraping were Fusarium solani (25%) and Trichosporon faecale (25%) in subtropical Taiwan; in tropical Taiwan was Fusarium spp. (50%). CONCLUSIONS: The identification rate of fungus was higher in tropical Taiwan than subtropical Taiwan. Awareness of the local epidemiology is crucial for early diagnosis of fungal keratitis in tropical area.

A rare case of Trichosporon mycotoxinivorans and Cryptococcus neoformans co-infection in lung.

A 70-year-old woman with liver cirrhosis caused by primary biliary cirrhosis and rheumatoid arthritis was found to have multiple pulmonary nodular shadows in the right middle and lower lung fields on chest radiography. The multiple pulmonary nodules and masses rapidly increased over 2 months. Trichosporon mycotoxinivorans and Cryptococcus neoformans were identified in brushing specimens, bronchial lavage, and transbronchial lung biopsy specimens. The patient was diagnosed as having a co-infection of the lung with T. mycotoxinivorans and C. neoformans, and was treated with fluconazole. Although the pulmonary shadows were under control with treatment, she died 5 months later due to liver failure. We report herein a rare case of co-infection of the lung with T. mycotoxinivorans and C. neoformans.

Fatal Disseminated Infection by Trichosporon asahii Under Voriconazole Therapy in a Patient with Acute Myeloid Leukemia: A Review of Breakthrough Infections by Trichosporon spp.

INTRODUCTION: Cases of invasive Trichosporon infections have increasingly emerged; it is now the second leading cause of yeast bloodstream infections after Candida spp., particularly in the immunosuppressed population, where it often causes breakthrough fungemia with high mortality. METHODS: We present a case report of a breakthrough Trichosporon asahii infection in a patient with acute myeloid leukemia and review all of the cases of breakthrough Trichosporon spp. infections published in the literature to date. RESULTS: We extracted 68 cases of breakthrough Trichosporon spp. infections, wherein 95.5% patients had hematological malignancy, 61.8% of them occurred in the presence of echinocandins, 22% of triazoles, 13.2% of amphotericin and 3% of other combinations of antifungals. The most prevalent manifestation was fungemia (94%); 82.8% of these were associated with the presence of a central venous catheter. The overall mortality was 68.7%; the patients who survived recovered from the neutropenic event. CONCLUSIONS: Invasive trichosporonosis is an acute fatal condition that occurs in immunosuppressed patients, usually under antifungal selective pressure. Typically, neutropenia and its underlying diseases are associated with adverse outcomes.

Molecular Identification, Genotyping, Phenotyping, and Antifungal Susceptibilities of Medically Important Trichosporon, Apiotrichum, and Cutaneotrichosporon Species.

Recently, Trichosporon taxonomy has been reevaluated and new genera of the Trichosporonaceae family have been described. Here, 26 clinical isolates were submitted for identification via sequencing of the intergenic space 1 (IGS1) region, genotyping, and investigation of virulence factors. Antifungal susceptibility was determined using the CLSI broth microdilution method for fluconazole (FLC), itraconazole (ITC), and amphotericin B (AMB). Of these, 24 isolates were identified, including 12 T. asahii, 4 T. inkin, 3 T. faecale, 1 T. coremiiforme, 1 T. japonicum, 2 Cutaneotrichosporon dermatis (formerly T. dermatis), and 1 Apiotrichum mycotoxinivorans (formerly T. mycotoxinivorans). Species-level identification of 2 isolates was not successful; they were described as Trichosporon sp. We observed optimal colonial development at 35-40 °C. Lipase was the major extracellular enzyme produced (100%); caseinase was not produced (0%). Biofilms were produced by all isolates (classified as low). High AMB minimum inhibitory concentration (MIC) was observed, with all strains resistant. Fluconazole was the most active drug among the antifungals tested. However, high MICs for FLC were observed in C. dermatis and A. mycotoxinivorans species, which also showed resistance to ITC and AMB. This study, conducted in the Northern region of Brazil, identified 5 Trichosporon species along with C. dermatis and A. mycotoxinivorans and demonstrated their pathogenic potential through their ability to produce important virulence factors. This may contribute to our understanding of the epidemiology and factors related to the pathogeneses of species in the Trichosporonaceae family.

A case report of catheter-related bloodstream infection due to Trichosporon coremiiforme in a patient with secondary neutropenia to HIV.

Here, we describe an invasive infection due to Trichosporon coremiiforme in an HIV positive patient with neutropenia. The strain was first erroneously identified as Trichosporon asahii by conventional methods, but correctly identified by mass spectrometry using matrix-assisted laser desorption/ionization time-of-flight technology (MALDI-TOF MS) and ribosomal DNA sequencing. The infection was successfully resolved after antifungal treatment with amphotericin B and fluconazole. This case report is a contribution to the study of T. coremiiforme infections and reinforces its relevance as a species capable of causing invasive human infection in immunocompromised patients and also contributes to the study of its susceptibility profile against antifungal drugs.

Mixed Infection of Toe Nail Caused by Trichosporon asahii and Rhodotorula mucilaginosa.

Trichosporon asahii and Rhodotorula mucilaginosa are important fungal species causing disseminated disease in immunocompromised patients. Onychomycosis prevalence rate ranges from 2 to 30%, which were 50% of nail diseases and 30% of superficial mycosis, respectively. Although important, little is known about the co-habitation of T. asahii and R. mucilaginosa in the causation of onychomycosis. Here, we present the co-habitation of T. asahii and R. mucilaginosa as causative agents of onychomycosis in a healthy 41-year-old male in China. Direct microscopic examination, fungal culture and MALDI-TOF MS were employed in isolated pathogens; hence, antifungal susceptibility test was evaluated. T. asahii was sensitive to posaconazole, voriconazole and itraconazole, whereas R. mucilaginosa was sensitive to both 5-flucytosine and amphotericin B. This report highlights the co-habitation of T. asahii and R. mucilaginosa in the causation of onychomycosis and to raise the awareness of this infection among dermatologists.

Identification of medically important yeasts by sequence analysis of the internal transcribed spacer and D1/D2 region of the large ribosomal subunit / Identificación de levaduras de interés médico mediante análisis de secuencia del espaciador interno transcrito y de la región D1/D2 de la subunidad ribosómica grande

Background: The prevalence of opportunistic yeast infections has increased in recent decades as the result of an increasing immunocompromised patient population. Aims: To evaluate ribosomal RNA (rRNA) gene sequence to identify medically important yeast species, to investigate the performance of both the rRNA gene internal transcribed spacer (ITS) and D1/D2 region in identifying clinically relevant yeasts, and to compare these results with those of a standard phenotypic method. Methods: Both regions from 50 yeast strains, comprising 45 clinical isolates and 5 reference strains, were amplified using PCR and then sequenced. The sequences were compared to reference data available from the GenBank database of the National Center for Biotechnology Information using the BLASTn tool. Results: Using ID32C, 88% (44/50) of all strains were identified accurately at the species level, although 6% were misidentified; two Candida eremophila isolates were identified as Candida glabrata and Candida tropicalis, and one Saprochaete clavata isolate was identified as Saprochaete capitata. Two of the four isolates identified by phenotypic methods as Trichosporon asahii were defined so by analyzing the ITS region, but the remaining two were not distinguishable from closely related species. Based on the D1/D2 region, these four isolates had 100% sequence identity with T. asahii, Trichosporon japonicum, and Trichosporon asteroides. The isolate identified as Trichosporon inkin using ID32C could not be distinguished from Trichosporon ovoides by analyzing the ITS and D1/D2 regions. Conclusions: Identifying medically important yeasts by sequencing the ITS and D1/D2 region is a rapid and reliable alternative to conventional identification methods. For a diagnostic algorithm, we suggest a two-step procedure integrating conventional methods (e.g. microscopic morphology on corn meal agar with Tween(R) 80 and API ID32C(R)) and sequence analysis of the ITS and D1/D2 region

Antecedentes: La prevalencia de infecciones oportunistas por levaduras ha aumentado en las últimas décadas como resultado de una población de pacientes inmunocomprometidos cada vez mayor. Objetivos: Evaluar la secuencia del gen del ARN ribosomal (ARNr) para identificar especies de levaduras médicamente importantes, investigar el rendimiento del espaciador transcrito interno del gen ARNr (ITS) y las regiones D1/D2 en la identificación de levaduras clínicamente relevantes, y comparar estos resultados con los de un método fenotípico estándar. Métodos: Ambas regiones del ARNr de 50 cepas de levaduras con 45 aislamientos clínicos y 5 cepas de referencia se amplificaron mediante PCR y posteriormente se secuenciaron. Las secuencias se compararon con los datos de referencia disponibles en la base de datos GenBank(R) del Centro Nacional de Información Biotecnológica mediante la herramienta BLASTn. Resultados: Mediante el método ID32C el 88% (44/50) de todas las cepas se identificaron con precisión y el 6% se identificaron erróneamente; dos aislamientos de Candida eremophila fueron identificados como Candida glabrata y Candida tropicalis, y un aislamiento de Saprochaete clavata fue identificado como Saprochaete capitata. Dos de los cuatro aislamientos identificados por métodos fenotípicos como Trichosporon asahii se catalogaron así al analizar la región ITS, pero las dos restantes no se distinguían de las especies estrechamente relacionadas. En base a la secuencia de la región D1/D2, estos cuatro aislamientos se identificaron, con un 100% de similitud, como T. asahii, Trichosporon japonicum y Trichosporon asteroides. El aislamiento identificado como Trichosporon inkin mediante ID32C no se pudo distinguir de Trichosporon ovoides al analizar las regiones ITS y D1/D2. Conclusiones: La identificación de levaduras de interés médico mediante la secuenciación de las regiones ITS y D1/D2 es una alternativa rápida y confiable a los métodos de identificación convencionales. Para un algoritmo de diagnóstico sugerimos un procedimiento de dos pasos que integre métodos convencionales (morfología microscópica en agar de harina de maíz con Tween(R) 80 y API ID32C(R)) y análisis de la secuencia de las regiones ITS y D1/D2

Acremonium and trichosporon fungal keratoconjunctivitis in a Leopard Gecko (Eublepharis macularius).

A 6-year-old male leopard gecko (Eublepharis macularius) was presented with a 2-year history of recurrent dysecdysis involving the ocular surface of both eyes. Ophthalmic examination revealed ocular surface desiccation and multifocal superficial ulcerative keratitis with patchy remnants of retained shed. Other abnormalities included stomatitis and mandibular and maxillary osteomyelitis. Topical and systemic antibiotic therapy, oral vitamin A, and improved husbandry conditions resolved the stomatitis and osteomyelitis but did not improve the ocular surface. Corneal cytology collected with a cytobrush revealed branching hyphae and budding yeast consistent with fungal keratitis. Fungal culture grew Acremonium sp. and Trichosporon sp. The addition of topical antifungal therapy improved the ocular surface health, but the patient was euthanized 7 weeks after initial presentation for persistent vomiting and dyspnea. Necropsy was declined. This case describes the first case of fungal keratitis caused by Acremonium sp. and Trichosporon sp. in a reptile.

Identification, genotyping, and pathogenicity of Trichosporon spp. Isolated from Giant pandas (Ailuropoda melanoleuca).

BACKGROUND: Trichosporon is the dominant genus of epidermal fungi in giant pandas (Ailuropoda melanoleuca) and causes local and deep infections. To provide the information needed for the diagnosis and treatment of trichosporosis in giant pandas, the sequence of ITS, D1/D2, and IGS1 loci in 29 isolates of Trichosporon spp. which were isolated from the body surface of giant pandas were combination to investigate interspecies identification and genotype. Morphological development was examined via slide culture. Additionally, mice were infected by skin inunction, intraperitoneal injection, and subcutaneous injection for evaluation of pathogenicity. RESULTS: The twenty-nine isolates of Trichosporon spp. were identified as 11 species, and Trichosporon jirovecii and T. asteroides were the commonest species. Four strains of T. laibachii and one strain of T. moniliiforme were found to be of novel genotypes, and T. jirovecii was identified to be genotype 1. T. asteroides had the same genotype which involved in disseminated trichosporosis. The morphological development processes of the Trichosporon spp. were clearly different, especially in the processes of single-spore development. Pathogenicity studies showed that 7 species damaged the liver and skin in mice, and their pathogenicity was stronger than other 4 species. T. asteroides had the strongest pathogenicity and might provoke invasive infection. The pathological characteristics of liver and skin infections caused by different Trichosporon spp. were similar. CONCLUSIONS: Multiple species of Trichosporon were identified on the skin surface of giant panda, which varied in morphological development and pathogenicity. Combination of ITS, D1/D2, and IGS1 loci analysis, and morphological development process can effectively identify the genotype of Trichosporon spp.

A case of Trichosporon asahii urinary tract infection in a frail elderly patient.

Trichosporon urinary tract infection (UTI) is an unusual emerging infection, caused mostly by Trichosporon asahii, described especially in hospitalized patients. To date the interpretation and management of Trichosporon positive urinary culture remains a diagnostic and therapeutic dilemma for which there are no precise indications, and the challenge can be even more complicated in comorbid frail elderly patients. Triazoles are known to be the most effective antifungal drugs but can raise concerns about pharmacological interaction. We report a case of Trichosporon asahii nosocomial UTI in an elderly patient.

Molecular identification and biological characteristic analysis of an Apiotrichum mycotoxinivorans (formerly Trichosporon mycotoxinivorans) strain isolated from sputum specimens of a pediatric patient with pneumonia.

Apiotrichum mycotoxinivorans (formerly Trichosporon mycotoxinivorans) has long been used to degrade fungal toxins in livestock feed. However, clinic reports about this type of fungus are rare. In this study, we report the morphology, biochemistry, and molecular characteristics of an A. mycotoxinivorans strain isolated from a pediatric patient with congenital ventricular septal defect and pneumonia. A female patient, 26 months old, presented with congenital ventricular septal defect. Pulmonary infection symptoms were observed after the patient received cardiac repair surgery. Sputum bacterial and fungal cultures were positive for Elizabethkingia anophelis and a fungus, which was not readily identifiable using biochemical identification, or MALDI-TOF MS analysis. The strain was finally identified as A. mycotoxinivorans using amplification and sequencing of the D1/D2 region of 26S rDNA, ITS, and IGS1. Antifungal susceptibility test results suggested that fluconazole or voriconazole may be an appropriate choice for antifungal therapy. A biodegradability of ochratoxin A was considered as a characteristic of the fungal strain. Our results support the existing evidence that A. mycotoxinivorans is an opportunistic pathogen for human beings. Nucleic acid analysis allows for the accurate identification of the species in instances where conventional identification methods such as biochemical testing and MALDI-TOF MS may be unsuccessful.

Microbes Producing L-Asparaginase free of Glutaminase and Urease isolated from Extreme Locations of Antarctic Soil and Moss.

L-Asparaginase (L-asparagine aminohydrolase, E.C. 3.5.1.1) has been proven to be competent in treating Acute Lymphoblastic Leukaemia (ALL), which is widely observed in paediatric and adult groups. Currently, clinical L-Asparaginase formulations are derived from bacterial sources such as Escherichia coli and Erwinia chrysanthemi. These formulations when administered to ALL patients lead to several immunological and hypersensitive reactions. Hence, additional purification steps are required to remove toxicity induced by the amalgamation of other enzymes like glutaminase and urease. Production of L-Asparaginase that is free of glutaminase and urease is a major area of research. In this paper, we report the screening and isolation of fungal species collected from the soil and mosses in the Schirmacher Hills, Dronning Maud Land, Antarctica, that produce L-Asparaginase free of glutaminase and urease. A total of 55 isolates were obtained from 33 environmental samples that were tested by conventional plate techniques using Phenol red and Bromothymol blue as indicators. Among the isolated fungi, 30 isolates showed L-Asparaginase free of glutaminase and urease. The L-Asparaginase producing strain Trichosporon asahii IBBLA1, which showed the highest zone index, was then optimized with a Taguchi design. Optimum enzyme activity of 20.57 U mL-1 was obtained at a temperature of 30 °C and pH of 7.0 after 60 hours. Our work suggests that isolation of fungi from extreme environments such as Antarctica may lead to an important advancement in therapeutic applications with fewer side effects.

Farnesol inhibits planktonic cells and antifungal-tolerant biofilms of Trichosporon asahii and Trichosporon inkin.

Trichosporon species have been considered important agents of opportunistic systemic infections, mainly among immunocompromised patients. Infections by Trichosporon spp. are generally associated with biofilm formation in invasive medical devices. These communities are resistant to therapeutic antifungals, and therefore the search for anti-biofilm molecules is necessary. This study evaluated the inhibitory effect of farnesol against planktonic and sessile cells of clinical Trichosporon asahii (n = 3) andTrichosporon inkin (n = 7) strains. Biofilms were evaluated during adhesion, development stages and after maturation for metabolic activity, biomass and protease activity, as well as regarding morphology and ultrastructure by optical microscopy, confocal laser scanning microscopy, and scanning electron microscopy. Farnesol inhibited Trichosporon planktonic growth by 80% at concentrations ranging from 600 to 1200 µM for T. asahii and from 75 to 600 µM for T. inkin. Farnesol was able to reduce cell adhesion by 80% at 300 µM for T. asahii and T. inkin at 600 µM, while biofilm development of both species was inhibited by 80% at concentration of 150 µM, altering their structure. After biofilm maturation, farnesol decreased T. asahii biofilm formation by 50% at 600 µM concentration and T. inkin formation at 300 µM. Farnesol inhibited gradual filamentation in a concentration range between 600 and 1200 µM. Farnesol caused reduction of filament structures of Trichosporon spp. at every stage of biofilm development analyzed. These data show the potential of farnesol as an anti-biofilm molecule.