Molecular identification and susceptibility of Trichosporon species isolated from clinical specimens in Qatar: isolation of Trichosporon dohaense Taj-Aldeen, Meis & Boekhout sp. nov

Diversity of dung beetle-associated yeasts from pristine environments of Botswana

Yeast-insect interactions are increasingly becoming an attractive source of discovery for previously unknown, unique, diverse, and industrially relevant yeast species. Despite a wealth of studies that have recently focused on yeasts in symbiotic association with Hymenopteran insects, yeasts associated with Coleopteran insects, such as lignocellulosic-rich dung-dependent beetles, remain poorly studied. Trends in yeast discovery suggest that species richness and diversity can be attributed to the ecological niche of the insect. Here, we considered the potential of dung beetles inhabiting the extreme environments of Botswana, characterized by desert-like conditions (semi-arid to arid and hot) as well as protected pristine environments, as possible attribute niches that can shape the extremophilic and diverse life history strategies of yeasts. We obtained a total of 97 phylogenetically diverse yeast isolates from six species of dung beetles from Botswana's unexplored environments, representing 19 species belonging to 11 genera. The findings suggest that the guts of dung beetles are a rich niche for non-Saccharomyces yeast species. Meyerozyma and Pichia were the most dominant genera associated with dung beetles, representing 55% (53 out of 97) of the yeast isolates in our study. Trichosporon and Cutaneotrichosporon genera represented 32% (31 out of 97) of the isolates. The remaining isolates belonged to Apiotrichum, Candida, Diutina, Naganishia, Rhodotorula, and Wickerhamiella genera (12 out of 97). We found out that about 62% (60 out of 97) of the isolates were potentially new species because of their low internal transcribed spacer (ITS) sequence similarity when compared to the most recent optimal species delineation threshold. A single isolate was unidentifiable using the ITS sequences. Using an in silico polymerase chain reaction-restriction fragment length polymorphism approach, we revealed that there was genetic diversity within isolates of the same species. Our results contribute to the knowledge and understanding of the diversity of dung beetle-associated yeasts.

Application of Membrane Filtration to Cold Sterilization of Drinks and Establishment of Aseptic Workshop

Aseptic packaging of high quality beverage is necessary and its cold-pasteurization or sterilization is vital. Studies on application of ultrafiltration or microfiltration membrane to cold- pasteurization or sterilization for the aseptic packaging of beverages have been reviewed. Designing and manufacturing ultrafiltration or microfiltration membrane systems for cold-pasteurization or sterilization of beverage are based on the understanding of size of microorganisms and theoretical achievement of filtration. It is concluded that adaptability of membrane filtration, especially its combination with other safe cold method, to cold- pasteurization and sterilization for the aseptic packaging of beverages should be assured without a shadow of doubt in future.

Metabolic and phenotypic plasticity may contribute for the higher virulence of Trichosporon asahii over other Trichosporonaceae members

BACKGROUND

The Trichosporonaceae family comprises a large number of basidiomycetes widely distributed in nature. Some of its members, especially Trichosporon asahii, have the ability to cause human infections. This ability is related to a series of virulence factors, which include lytic enzymes production, biofilm formation, resistance to oxidising agents, melanin and glucuronoxylomannan in the cell wall, metabolic plasticity and phenotypic switching. The last two are poorly addressed within human pathogenic Trichosporonaceae.

OBJECTIVE

These factors were herein studied to contribute with the knowledge of these emerging pathogens and to uncover mechanisms that would explain the higher frequency of T. asahii in human infections.

METHODS

We included 79 clinical isolates phenotypically identified as Trichosporon spp. and performed their molecular identification. Lactate and N-acetyl glucosamine were the carbon sources of metabolic plasticity studies. Morphologically altered colonies after subcultures and incubation at 37°C indicated phenotypic switching.

RESULTS AND CONCLUSION

The predominant species was T. asahii (n = 65), followed by Trichosporon inkin (n = 4), Apiotrichum montevideense (n = 3), Trichosporon japonicum (n = 2), Trichosporon faecale (n = 2), Cutaneotrichosporon debeurmannianum (n = 1), Trichosporon ovoides (n = 1) and Cutaneotrichosporon arboriforme (n = 1). T. asahii isolates had statistically higher growth on lactate and N-acetylglucosamine and on glucose during the first 72 h of culture. T. asahii, T. inkin and T. japonicum isolates were able to perform phenotypic switching. These results expand the virulence knowledge of Trichosporonaceae members and point for a role for metabolic plasticity and phenotypic switching on the trichosporonosis pathogenesis.

COVID-19-associated brain abscess caused by Trichosporon dohaense: A case report and review of literature

We report the first case of Coronavirus Disease 2019 (COVID-19)-associated brain abscess caused by a rare Trichosporon species, T. dohaense. The patient was a known diabetic and had received systemic corticosteroids for the treatment of COVID-19. He underwent craniotomy and evacuation of abscess. The pus aspirate grew a basidiomycetous yeast, morphologically resembling Trichosporon species. The isolate was initially misidentified by VITEK® MS due to lack of mass spectral database of T. dohaense. Accurate identification was achieved by internal transcribed spacer-directed panfungal polymerase chain reaction. The patient had a favorable outcome following surgical intervention and antifungal therapy.

Trichosporon inkin fungemia case report: clinical and laboratory management

Trichosporon species are emerging as opportunistic pathogens that mainly affect immunocompromised patients. Patients with onco-hematological diseases usually present with fungemia by Trichosporon species, especially by T. asahii. Reports of this infection by other species of the genus are uncommon. Thus, in this paper, we present a case of T. inkin fungemia in a 39-year-old female patient with intestinal obstruction and absence of malignant hematological diseases. The late mycological diagnosis, the ineffective control of her pre-existing conditions and consequent failure to start antifungal therapy were the contributing factors for the patient's death.

Comparing the phenotypic, genotypic, and proteomic identification of Trichosporon species: A globally emerging yeast of medical importance

Trichosporon spp. are widely distributed in the nature, comprising species that inhabit different ecological niches and can be found in the water, soil, and body surface of animals and humans. Such microorganisms have been classically associated with superficial infections; however, in the last decades, they have also been related to disseminated infections in immunocompromised patients, behaving as opportunistic agents, which demands rapid and accurate species identification for efficient therapy. Concordance level between the traditional phenotypic method and the molecular technique (gold standard) in the identification of all 59 Trichosporon samples was 59.3%. Identification concordance between MALDI-TOF spectrometry and the molecular technique was 71.2%. No isolate of environmental origin was identifiable by MALDI-TOF mass spectrometry (MS), and 100% of such environmental isolates were discordant for IGS region sequencing and phenotypic characterization. Both comparisons evidenced greatest concordance in the identification of T. asahii. The species T. debeurmannianum, T. dermatis, T. venhuisii and T. insectorum were not properly identified by both MALDI-TOF MS and the phenotypic technique. MALDI-TOF MS, in particular, seems to be appropriate to investigate yeasts of the genus Trichosporon; however, database updates are still necessary, especially for species that are not common in the clinical routine. With the aim of helping understand the aspects involved in early and accurate diagnosis of infections caused by this opportunistic agent, the present study compared the phenotypic, molecular (IGS region) and mass-spectrometry (MALDI-TOF) identification of 59 yeasts of the genus Trichosporon which had clinical and environmental origin and were kept in a mycology collection.

Where the infection is isolated rather than the specific species correlates with adherence strength, whereas biofilm density remains static in clinically isolated Candida and arthroconidial yeasts

To colonize and infect the host, arthroconidial yeasts must avoid being killed by the host's defenses. The formation of biofilms on implanted devices allows fungi to avoid host responses and to disseminate into the host. To better study the mechanisms of infection by arthroconidial yeasts, adherence and biofilm formation were assayed using patient samples collected over 10 years. In clinical samples, adherence varies within species, but the relative adherence is constant for those samples isolated from the same infection site. Herein we document, for the first time, in-vitro biofilm formation by Trichosporon dohaense, T. ovoides, T. japonicum, T. coremiiforme, Cutaneotrichosporon mucoides, Cutaneotrichosporon cutaneum, Galactomyces candidus, and Magnusiomyces capitatus on clinically relevant catheter material. Analysis of biofilm biomass assays indicated that biofilm mass changes less than 2-fold, regardless of the species. Our results support the hypothesis that most pathogenic fungi can form biofilms, and that biofilm formation is a source of systemic infections.

Multidrug-resistant Trichosporon species: underestimated fungal pathogens posing imminent threats in clinical settings

Species of Trichosporon and related genera are widely used in biotechnology and, hence, many species have their genome sequenced. Importantly, yeasts of the genus Trichosporon have been increasingly identified as a cause of life-threatening invasive trichosporonosis (IT) in humans and are associated with an exceptionally high mortality rate. Trichosporon spp. are intrinsically resistant to frontline antifungal agents, which accounts for numerous reports of therapeutic failure when echinocandins are used to treat IT. Moreover, these fungi have low sensitivity to polyenes and azoles and, therefore, are potentially regarded as multidrug-resistant pathogens. However, despite the clinical importance of Trichosporon spp., our understanding of their antifungal resistance mechanisms is quite limited. Furthermore, antifungal susceptibility testing is not standardized, and there is a lack of interpretive epidemiological cut-off values for minimal inhibitory concentrations to distinguish non-wild type Trichosporon isolates. The route of infection remains obscure and detailed clinical and environmental studies are required to determine whether the Trichosporon infections are endogenous or exogenous in nature. Although our knowledge on effective IT treatments is rather limited and future randomized clinical trials are required to identify the best antifungal agent, the current paradigm advocates the use of voriconazole, removal of central venous catheters and recovery from neutropenia.

MALDI-TOF MS characterisation, genetic diversity and antifungal susceptibility of Trichosporon species from Iranian clinical samples

BACKGROUND

Trichosporonosis is an emerging fungal infection caused by Trichosporon species, a genus of yeast-like fungi, which are frequently encountered in human infections ranging from mild cutaneous lesions to fungemia in immunocompromised patients. The incidence of trichosporonosis has increased in recent years, owing to higher numbers of individuals at risk for this infection. Although amphotericin B, posaconazole and isavuconazole are generally effective against Trichosporon species, some isolates may have variable susceptibility to these antifungals.

OBJECTIVES

Herein, we evaluated the species distribution, genetic diversity and antifungal susceptibility profiles of Trichosporon isolates in Iran.

METHODS

The yeasts were identified by matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOF MS). Phylogenetic analysis was performed based on amplified fragment length polymorphism (AFLP). The in vitro susceptibilities of eight antifungal agents were analysed using the Clinical and Laboratory Standards Institute broth microdilution methods.

RESULTS

The isolates belonged to the species T asahii (n = 20), T japonicum (n = 4) and T faecale (n = 3). A dendrogram of the AFLP analysis demonstrated that T asahii and non-asahii Trichosporon strains (T japonicum and T faecale) are phylogenetically distinct. While voriconazole was the most active agent (GM MIC = 0.075 μg/ml), high fluconazole MICs (8 μg/ml) were observed for a quarter of Trichosporon isolates. The GM MIC value of amphotericin B for T asahii and non-asahii Trichosporon species was 0.9 μg/ml.

CONCLUSIONS

The distribution and antifungal susceptibility patterns of the identified Trichosporon species could inform therapeutic choices for treating these emerging life-threatening fungi.

Amphotericin B and Other Polyenes-Discovery, Clinical Use, Mode of Action and Drug Resistance

Although polyenes were the first broad spectrum antifungal drugs on the market, after 70 years they are still the gold standard to treat a variety of fungal infections. Polyenes such as amphotericin B have a controversial image. They are the antifungal drug class with the broadest spectrum, resistance development is still relatively rare and fungicidal properties are extensive. Yet, they come with a significant host toxicity that limits their use. Relatively recently, the mode of action of polyenes has been revised, new mechanisms of drug resistance were discovered and emergent polyene resistant species such as Candida auris entered the picture. This review provides a short description of the history and clinical use of polyenes, and focusses on the ongoing debate concerning their mode of action, the diversity of resistance mechanisms discovered to date and the most recent trends in polyene resistance development.

Urinary Tract Infections Caused by Fluconazole-Resistant Trichosporon japonicum in 2 Kidney Transplant Patients and Analysis of Their Homology

Trichosporon spp. are emerging opportunistic agents that cause systemic diseases and life-threatening disseminated disease in immunocompromised hosts. Trichosporon japonicum is a highly rare cause of invasive trichosporonosis. In this study, we describe 2 cases of urinary tract infection caused by Trichosporon japonicum in kidney transplant patients. Culturing of urine samples yielded bluish-green colonies of T. japonicum on Candida chromogenic fungal medium. The isolates were identified as T. japonicum by matrix-assisted laser desorption ionization–time-of-flight mass spectrometry (MALDI TOF-MS; Autof MS 1000). The identification of T. japonicum was further confirmed by 18S rRNA gene sequencing. In vitro drug susceptibility testing showed that the 2 strains of T. japonicum were resistant to 5-flucytosine, fluconazole, and caspofungin, with dose-dependent sensitivity to itraconazole and voriconazole but sensitivity to amphotericin B. The homology of the 2 T. japonicum strains, as determined by cluster analysis and principal component analysis of MALDI-TOF MS, was ~85%, suggesting a common nosocomial origin. The first 2 case reports of fluconazole-resistant T. japonicum urinary infection in kidney transplant recipients are presented.

Epidemiological study of Trichosporon asahii infections over the past 23 years

Trichosporon is a yeast-like basidiomycete, a conditional pathogenic fungus that is rare in the clinic but often causes fatal infections in immunocompromised individuals. Trichosporon asahii is the most common pathogenic fungus in this genus and the occurrence of infections has dramatically increased in recent years. Here, we report a systematic literature review detailing 140 cases of T. asahii infection reported during the past 23 years. Statistical analysis shows that T. asahii infections were most frequently reported within immunodeficient or immunocompromised patients commonly with blood diseases. Antibiotic use, invasive medical equipment and chemotherapy were the leading risk factors for acquiring infection. In vitro susceptibility, clinical information and prognosis analysis showed that voriconazole is the primary drug of choice in the treatment of T. asahii infection. Combination treatment with voriconazole and amphotericin B did not show superiority over either drug alone. Finally, we found that the types of infections prevalent in China are significantly different from those in other countries. These results provide detailed information and relevant clinical treatment strategies for the diagnosis and treatment of T. asahii infection.

Identification of medically important yeasts by sequence analysis of the internal transcribed spacer and D1/D2 region of the large ribosomal subunit

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® 80 and API ID32C®) and sequence analysis of the ITS and D1/D2 region.

Exploring the resistance mechanisms in Trichosporon asahii: Triazoles as the last defense for invasive trichosporonosis

Trichosporon asahii has recently been recognized as an emergent fungal pathogen able to cause invasive infections in neutropenic cancer patients as well as in critically ill patients submitted to invasive medical procedures and broad-spectrum antibiotic therapy. T. asahii is the main pathogen associated with invasive trichosporonosis worldwide. Treatment of patients with invasive trichosporonosis remains a controversial issue, but triazoles are mentioned by most authors as the best first-line antifungal therapy. There is mounting evidence supporting the claim that fluconazole (FLC) resistance in T. asahii is emerging worldwide. Since 2000, 15 publications involving large collections of T. asahii isolates described non-wild type isolates for FLC and/or voriconazole. However, very few papers have addressed the epidemiology and molecular mechanism of antifungal resistance in Trichosporon spp. Data available suggest that continuous exposure to azoles can induce mutations in the ERG11 gene, resulting in resistance to this class of antifungal drugs. A recent report characterizing T. asahii azole-resistant strains found several genes differentially expressed and highly mutated, including genes related to the Target of Rapamycin (TOR) pathway, indicating that evolutionary modifications on this pathway induced by FLC stress may be involved in developing azole resistance. Finally, we provided new data suggesting that hyperactive efflux pumps may play a role as drug transporters in FLC resistant T. asahii strains.

Trichosporon japonicum Fungemia and Ventricular Assist Device Infection in an Immunocompetent Patient

Trichosporon species are emerging opportunistic yeasts that cause life-threatening disseminated disease in severely immunocompromised patients. Trichosporon japonicum is a very rare cause of invasive trichosporonosis. We describe a case of Trichosporon japonicum fungemia in an immunocompetent patient with a transcutaneous biventricular assist device.

Species distribution and antifungal susceptibility of 358 Trichosporon clinical isolates collected in 24 medical centres

OBJECTIVES

To provide species distribution and antifungal susceptibility profiles of 358 Trichosporon clinical isolates collected from 24 tertiary-care hospitals.

METHODS

Species identification was performed by sequencing the IGS1 region of rDNA. Antifungal susceptibility testing for amphotericin B, fluconazole, voriconazole and posaconazole followed the Clinical and Laboratory Standards Institute reference method. Tentative epidemiologic cutoff values (97.5% ECVs) of antifungals for Trichosporon asahii were also calculated.

RESULTS

Isolates were cultured mostly from urine (155/358, 43.3%) and blood (82/358, 23%) samples. Trichosporon asahii was the most common species (273/358, 76.3%), followed by T. inkin (35/358, 9.7%). Isolation of non-T. asahii species increased substantially over the last 11 years [11/77 (14.2%) from 1997 to 2007 vs. 74/281, (26.3%) from 2008 to 2018, p0.03]. Antifungal susceptibility testing showed high amphotericin B minimum inhibitory concentrations against Trichosporon isolates, with higher values for T. faecale. The ECV for amphotericin B and T. asahii was set at 4 μg/mL. Among the triazole derivatives, fluconazole was the least active drug. The ECVs for fluconazole and posaconazole against T. asahii were set at 8 and 0.5 μg/mL, respectively. Voriconazole showed the strongest in vitro activity against the Trichosporon isolates; its ECV for T. asahii was set at 0.25 μg/mL after 48 hours' incubation.

CONCLUSIONS

Trichosporon species diversity has increased over the years in human samples, and antifungal susceptibility profiles were species specific. Trichosporon asahii antifungal ECVs were proposed, which may be helpful to guide antifungal therapy.

Yeast identification by sequencing, biochemical kits, MALDI-TOF MS and rep-PCR DNA fingerprinting

No study has comprehensively evaluated the performance of 28S nrDNA and ITS sequencing, commercial biochemical test kits, MALDI-TOF MS platforms, and the emerging rep-PCR DNA fingerprinting technology using a cohort of yeast strains collected from a clinical microbiology laboratory. In this study, using 71 clinically important yeast isolates (excluding Candida albicans) collected from a single centre, we determined the concordance of 28S nrDNA and ITS sequencing and evaluated the performance of two commercial test kits, two MALDI-TOF MS platforms, and rep-PCR DNA fingerprinting. 28S nrDNA and ITS sequencing showed complete agreement on the identities of the 71 isolates. Using sequencing results as the standard, 78.9% and 71.8% isolates were correctly identified using the API 20C AUX and Vitek 2 YST ID Card systems, respectively; and 90.1% and 80.3% isolates were correctly identified using the Bruker and Vitek MALDI-TOF MS platforms, respectively. Of the 18 strains belonging to the Candida parapsilosis species complex tested by DiversiLab automated rep-PCR DNA fingerprinting, all were identified only as Candida parapsilosis with similarities ≥93.2%, indicating the misidentification of Candida metapsilosis and Candida orthopsilosis. However, hierarchical cluster analysis of the rep-PCR DNA fingerprints of these three species within this species complex formed three different discrete clusters, indicating that this technology can potentially differentiate the three species. To achieve higher accuracies of identification, the databases of commercial biochemical test kits, MALDI-TOF MS platforms, and DiversiLab automated rep-PCR DNA fingerprinting needs further enrichment, particularly for uncommonly encountered yeast species.

Trichosporon dohaense, a rare pathogen of human invasive infections, and literature review

Background

Trichosporon dohaense is a rare fungal species that has not been described in human invasive infections.

Patients and methods

In this study, we investigated two T. dohaense isolates from patients with invasive infections in two hospitals in China, as part of the China Hospital Invasive Fungal Surveillance Net (CHIF-NET) program. Both patients were under immunocompromised conditions.

Results

On chromogenic agar, T. dohaense isolates were dark blue, similar to the color of Candida. tropicalis, but the characteristic moist colony appearance was quite different from that of T. asahii. The two isolates were misidentified as T. asahii and T. inkin by the VITEK 2 YST system. The rDNA internal transcribed spacer (ITS) region and the D1/D2 domain sequences of the two T. dohaense isolates were 100% identical to T. dohaense type strain CBS10761^T. The sequence of the intergenic spacer region-1 also clearly distinguished the species. Of the three matrix-assisted laser desorption/ionization time-of-flight mass spectrometry systems, Bruker Biotyper and Autobio MS correctly identified the two isolates to species level, whereas Vitek MS systems misidentified them as T. ovoides or T. asteroides. Echinocandins exhibited no in vitro activities against the two T. dohaense isolates. In addition, the isolates exhibited intermediate susceptibility to fluconazole (with minimal inhibitory concentrations [MICs] of 8 and 16 µg/mL) and itraconazole, voriconazole, and posaconazole (MICs of 0.25-1 µg/mL). T. dohaense demonstrated susceptibility to amphotericin B with MIC of 1 µg/mL. The MICs of fluconazole and voriconazole in our study were higher than the MIC₅₀ of 62 for T. asahii isolates (4 and 0.064 µg/mL) in the CHIF-NET program.

Conclusion

This case study points to a possible emergence of T. dohaense as an opportunistic human invasive fungal pathogen, and the reduced susceptibility should be noted.

Trichosporon inkin meningitis in Northeast Brazil: first case report and review of the literature

Background

Trichosporon species may colonize the skin, respiratory tract and gastrointestinal tract of human beings. The yeast is recognized as etiological agent of white piedra, a superficial mycosis. Nevertheless, immunocompromised hosts may develop invasive Trichosporonosis. Central nervous system trichosporonosis is a very rare clinical manifestation. In fact, only a few cases have been published in the literature and none of them was caused by Trichosporon inkin.

Case presentation

Here we report the first clinical case of meningoencephalitis due to this species in a female previously healthy patient under corticosteroids and antibiotics therapy for several months. She was submitted to an invasive procedure to remove a left sided acoustic neuroma and further developed a cerebrospinal fistula. After some days of the procedure, she presented a predominantly and intensive occipital holocranial headache, followed by vomiting, hyporexia, weight loss, asthenia, irritability, difficulty to concentrate and rotator vertigo. The patient further developed a cerebrospinal fistula in the occipital region and was submitted to a surgical correction. After several months of clinical interventions, she was diagnosed with CNS Trichosporonosis, after Magnetic Resonance Imaging and positive microbiological cultures obtained within two different occasions (2 weeks apart). Despite the antifungal therapy with Amphotericin B and Voriconazole, the patient did not survive.

Conclusions

Despite CNS Fungal infections are mostly due to Cryptococcus spp., other emergent yeasts, such as T. inkin may be considered as a likely etiological agent. This is the first case report of CNS Trichosporonosis, where species identification was performed with rDNA sequencing.

Trichosporon loubieri Fungemia in a 39-Year-Old Caucasian Woman With B-Cell Lymphoblastic Leukemia

We report a case of Trichosporon loubieri (T. loubieri) fungemia with likely liver involvement in a 39-year-old Caucasian patient with relapsed B-cell acute lymphoblastic leukemia after an allogeneic hematopoietic cell transplant. This is the fifth published case of T. loubieri infection and only the third case of T. loubieri fungemia, to our knowledge. All 3 cases of T. loubieri infection with fungemia had liver involvement.

Trichosporon isolation from human ungueal infections: is there a pathogenic role?

BACKGROUND

Although dermatophytes are considered the major cause of onychomycosis, many reports have incriminated non-dermatophyte moulds and yeasts in the disease’s etiology. Successive Trichosporon isolation from onychomycosis has led to the genus being suspected as a nail primary pathogen.

OBJECTIVE

To determine the prevalence of Trichosporon isolation in onychomycosis patients who attended a mycology diagnostic service in Rio de Janeiro, Brazil, between January 2003 and December 2006. The study also includes a worldwide review on Trichosporon isolation prevalence in ungueal disease, emphasizing T. ovoides.

METHODS

This retrospective study was conducted with the support of staff from the Mycology Laboratory at the Dermatological Service of Rio de Janeiro’s Santa Casa da Misericórdia (MLDS).

RESULTS

Mycological analysis provided positive results equaling 47/5036 (0.93%) for Trichosporon spp.; obtained mainly as a single agent (72.35%), and from mixed cultures (27.65%; X2= 6.397; p= 0.018). The great majority belongs to the T. ovoides species (91.5%; n=43), obtained as a single isolate (74.41%; n= 32/43; X2 = 7.023; p= 0.014).

CONCLUSIONS

Although T. ovoides is classically associated as an etiologic agent of white piedra, this study highlights its potential as a human nail disease pathogen. Our study opens doors for future epidemiologic and virulence factors aimed at determining whether T. ovoides is an important causative agent of onychomycosis in Brazil.

Incidence and biodiversity of yeasts, dermatophytes and non-dermatophytes in superficial skin infections in Assiut, Egypt

OBJECTIVE

The aim was to identify the incidence of the causal agents from dermatophytes, non-dermatophytes and yeasts in Assiut Governorate employing, beside the morphological and physiological techniques, the genotypic ones.

PATIENTS

Samples from infected nails, skin and hair were taken from 125 patients.

MATERIALS AND METHODS

Patients who presented with onychomycosis, tinea capitis, tinea corporis, tinea cruris and tinea pedis during the period from February 2012 to October 2015 were clinically examined and diagnosed by dermatologists and were guided to Assiut University Mycological Centre for direct microscopic examination, culturing and identification.

RESULTS

Onychomycosis was the most common infecting (64.8% of the cases) followed by tinea capitis (17.6%). Direct microscopic preparations showed only 45 positive cases, while 96 cases showed positive cultures. Infections were more frequent in females than males. Fifty-one fungal species and 1 variety were obtained. Yeasts were the main agents being cultured from 46.02% of total cases. Non-dermatophytes were the second etiologic agents. Aspergillus was responsible for infecting 19.47% of total cases and dermatophytes appeared in only 15.93% of the cases.

CONCLUSIONS

Yeasts were the main causal agents followed by non-dermatophytic fungi (mainly species of Aspergillus, then Alternaria, Scopulariopsis and Fusarium). Both direct microscopic preparations and culturing are recommended for mycological evaluation of clinical specimens. Sequence analysis of ITS region is recommended for yeast identification.

Invasive Trichosporon Infection: a Systematic Review on a Re-emerging Fungal Pathogen

Objectives: This review aimed to better depict the clinical features and address the issue of therapeutic management of Trichosporon deep-seated infections.

Methods: We comprehensively reviewed the cases of invasive Trichosporon infection reported in the literature from 1994 (date of taxonomic modification) to 2015. Data from antifungal susceptibility testing (AST) studies were also analyzed.

Results: Two hundred and three cases were retained and split into four groups: homeopathy (n = 79), other immunodeficiency conditions (n = 41), miscellaneous (n = 58) and newborns (n = 25). Trichosporon asahii was the main causative species (46.7%) and may exhibit cross-resistance to different antifungal classes. The unfavorable outcome rate was at 44.3%. By multivariate analysis, breakthrough infection (OR 2.45) was associated with unfavorable outcome, whilst the use of an azole-based therapy improved the prognosis (OR 0.16). Voriconazole-based treatment was associated with favorable outcome in hematological patients (73.6 vs. 41.8%; p = 0.016). Compiled data from AST demonstrated that (i) T. asahii exhibits the highest MICs to amphotericin B and (ii) voriconazole has the best in vitro efficacy against clinical isolates of Trichosporon spp.

Conclusions:Trichosporon infection is not only restricted to hematological patients. Analysis of compiled data from AST and clinical outcome support the use of voriconazole as first line therapy.

New insights on the phylogeny and biology of the fungal ant pathogen Aegeritella

This paper evaluates the phylogenetic position of the ectoparasitic fungus Aegeritella tuberculata Bałazy & Wiśniewski, and broadly discusses its presence on ants in southern Poland. Field work was conducted in the Silesian Beskid Mountains in 2011-2013. The fungus was found on four species of ants: Lasius niger L., Lasius brunneus Latr., Formica lemani Bondr. and Formica fusca L. The first three species have not been noted previously in the literature as hosts of Aegeritella fungi. The infection rate ranged from 1% for Formica lemani to 21% for L. brunneus. Molecular analysis based on ITS and SSU rDNA sequences revealed close relationships between Aegeritella and Trichosporon isolates. We conclude that the genus Aegeritella-inceratae sedis until now, should be placed within the fungal group Basidiomycota, Tremellomycetes, Tremellomycetidae, Tremellales, Trichosporonaceae.

Subcutaneous Infection Associated with Trichosporon ovoides: A Case Report and Review of Literature

Trichosporon species are opportunistic yeasts which can cause infections, especially in immunocompromised patients. This is a report of Trichosporon ovoides that caused subcutaneous infection in a patient with underlying ischemic heart disease. The identification of fungal isolate was confirmed by PCR sequencing of ITS and large subunit regions in rRNA gene. In vitro susceptibility study showed that the isolate was susceptible to amphotericin B, fluconazole and voriconazole, and resistant to caspofungin, anidulafungin and itraconazole. The lesion improved after treatment with oral fluconazole and topical miconazole.

Epidemiology and Outcome of Trichosporon Fungemia: A Review of 185 Reported Cases From 1975 to 2014

We first reviewed the English-language literature for reported cases of Trichosporon fungemia over the past four decades, and did comprehensive analysis in order to guide our understanding of epidemiology and outcome-related aspects, especially the antifungal treatment and CVC management.

Background. Trichosporon species have emerged as an important non-Candida spp yeast pathogen in immunocompromised patients in recent decades; however, the systemic analysis of Trichosporon epidemiology has seldom been reported.

Methods. We reviewed 185 reported cases of Trichosporon fungemia from 1975 to 2014 in the English-language literature, and the epidemiology and prognostic factors of the included cases are described.

Results. The number of cases reported has increased with time, especially over the past decade. During the 3 decades from 1975 to 2004, the most commonly used antifungal compounds were amphotericin B/liposomal amphotericin B; however, in recent decades (2005–2014), triazoles (especially voriconazole) have become the most widely used agents, significantly improving outcome in the reported cases. Correlation analysis revealed that negative outcome is associated with several prognostic factors, including a history of antimicrobial use, bacterial bloodstream coinfection, prophylactic/empirical antifungal therapy, Trichosporon beigelii infection, and receiving the antifungal regimen of amphotericin B/liposomal amphotericin B. In addition, a significantly greater proportion of patients with a positive outcome had fungemia without invasive tissue infection and received a voriconazole regimen or an AmB-triazole combined regimen. Significant positive outcome was also associated with patients who had recovered from neutropenia or after central venous catheter removal.

Conclusions. Voriconazole can be recommended as a first-line antifungal compound to treat Trichosporon fungemia; the immune status of the host plays a crucial role in the outcome of this infection, and the removal of vascular catheters should be considered if feasible.

Trichosporon faecale invasive infection in a patient with severe aplastic anemia: Efficacy of voriconazole and liposomal amphotericin B before neutrophil recovery

We report a case of a 51-year old man with a severe aplastic anemia who developed an invasive trichosporonosis to Trichosporon faecale with fungemia and skin lesions during severe neutropenia. The treatment was successful before neutrophil recovery with a combination of voriconazole and liposomal amphotericin B.

Isavuconazole

Objective: To review the pharmacology, chemistry, in vitro susceptibility, pharmacokinetics, clinical efficacy, safety, tolerability, dosage, and administration of isavuconazole, a triazole antifungal agent. Data Sources: Studies and reviews were identified through an English language MEDLINE search (1978 to March 2015) and from http://www.clinicaltrials.gov , Food and Drug Administration (FDA) briefing documents, program abstracts from international symposia, and the manufacturer’s Web site. Study Selection and Data Extraction: All published and unpublished trials, abstracts, in vitro and preclinical studies, and FDA briefing documents were reviewed. Data Synthesis: Isavuconazole has activity against a number of clinically important yeasts and molds, including Candida spp, Aspergillus spp, Cryptococcus neoformans, and Trichosporon spp and variable activity against the Mucorales. Isavuconazole, available for both oral and intravenous administration, is characterized by slow elimination allowing once-daily dosing, extensive tissue distribution, and high (>99%) protein binding. The most commonly reported adverse events, which are mild and limited in nature, include nausea, diarrhea, and elevated liver function tests. Its drug interaction potential appears to be similar to other azole antifungals but less than those observed with voriconazole. Comparative trials are under way or have been recently completed for the treatment of candidemia, invasive candidiasis and aspergillosis, and rare mold infections. Conclusions: Isavuconazole has a broad spectrum of activity and favorable pharmacokinetic properties, providing an advantage over other currently available broad-spectrum azole antifungals and a clinically useful alternative to voriconazole for the treatment of invasive aspergillosis. It may also prove useful for the treatment of candidemia and invasive mold infections; however, these indications await the results of clinical trials.

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Local or general fungal infection remain a very serious event in burns. Burns have numerous risk factors for such, infections associated with depressed immunity. Candida, Aspergillus and mucor fungi prevail in wound infections. The two latest are especially serious and impairing. Diagnosis is based on anatomo-pathological and mycological examination of skin samples. Treatment is mainly surgical. Medical therapy depends on antifungal susceptibility. Most fungemias are candidemias. Diagnosis is difficult and often based on clinical suspicion. Treatment uses echinocandin and fluconazole.

Trichosporon asahii infection presenting as chronic meningo-ventriculitis and intra ventricular fungal ball: a case report and literature review

Central nervous system trichosporonosis is a rare clinical entity and so far only six cases including three each of brain abscess and meningitis has been on record. We report a rare case of chronic meningo-ventriculitis and intraventricular fungal ball due to Trichosporon asahii in an 18-year-old immunocompetent male from Burundi, east Africa. Neuroendoscopy showed multiple nodules and a fungal ball within the ventricle, which on culture grew T. asahii. He was initially empirically treated with liposomal amphotericin B. However, the antifungal susceptibility testing of T. asahii isolate revealed high minimum inhibitory concentration for amphotericin B (2 μg ml⁻¹), flucytosine (16 μg ml⁻¹) and caspofungin (2 μg ml⁻¹) but exhibited potent activity for voriconazole, posaconazole, itraconazole and fluconazole. The patient rapidly succumbed to cardiac arrest before antifungal therapy could be changed. Although disseminated trichosporonosis has been increasingly reported the diagnosis represents a challenge especially in rare clinical settings such as intraventricular fungal ball in the present case, which has not been described previously.

Fungemia due to Trichosporon mucoides in a diabetes mellitus patient: a rare case report

Trichosporon species are widely distributed in nature and can occasionally belong to the human microbiota. For many years, Trichosporon beigelii, the only species of this genus, was found as the aetiological agent of superficial skin infection called white piedra. However, many cases of invasive trichosporonosis caused by different newly delineated species of Trichosporon have been published in increasing numbers in recent past years, especially in immunocompromised persons. We report a rare case of fungemia due to Trichosporon mucoides in a diabetes mellitus patient, which will add to the emerging list of trichosporonosis infections.

Usefulness of matrix-assisted laser desorption ionisation-time-of-flight mass spectrometry for identifying clinical Trichosporon isolates

Trichosporon spp. have recently emerged as significant human pathogens. Identification of these species is important, both for epidemiological purposes and for therapeutic management, but conventional identification based on biochemical traits is hindered by the lack of updates to the species databases provided by the different commercial systems. In this study, 93 strains, or isolates, belonging to 16 Trichosporon species were subjected to both molecular identification using IGS1 gene sequencing and matrix-assisted laser desorption ionisation-time-of-flight (MALDI-TOF) analysis. Our results confirmed the limits of biochemical systems for identifying Trichosporon species, because only 27 (36%) of the isolates were correctly identified using them. Different protein extraction procedures were evaluated, revealing that incubation for 30 min with 70% formic acid yields the spectra with the highest scores. Among the six different reference spectra databases that were tested, a specific one composed of 18 reference strains plus seven clinical isolates allowed the correct identification of 67 of the 68 clinical isolates (98.5%). Although until recently it has been less widely applied to the basidiomycetous fungi, MALDI-TOF appears to be a valuable tool for identifying clinical Trichosporon isolates at the species level.