Trichosporon beigelii: a life-threatening pathogen in immunocompromised hosts

The Prevalence and Risk Factors of Trichosporonosis at King Abdulaziz University Hospital

Background

Fungal infections, especially those caused have emerged as a significant medical concern over the past three decades, particularly among immunocompromised patients. However, recent studies have highlighted the increasing prevalence of fungal infections resembling yeast other than Candida, such as trichosporonosis, especially among immunosuppressed individuals worldwide. Trichosporon has been identified as a significant contributor to superficial and invasive infections. Invasive trichosporonosis, primarily affecting immunocompromised patients, poses a significant threat with high mortality rates.

Purpose

The current study aimed to explore the clinical epidemiology of Trichosporon spp at King Abdulaziz University Hospital (KAUH) in Saudi Arabia.

Methods

This retrospective study aimed to assess the clinical epidemiology of Trichosporon spp. infections in microbiology cultures obtained from KAUH in Saudi Arabia. The study analyzed data from patients over a five-year period, focusing on demographic, clinical, and microbiological characteristics.

Results

This study encompassed 21 participants, categorized into four distinct age groups. Moreover, this study indicated T. asahii as the predominant species isolated, accounting for 90.5% of infections, followed by T. mucoides (9.5%). ICU hospitalization, diabetes mellitus, taking immunosuppressive drugs, and antifungal drugs, and the use of invasive medical equipment were identified as prominent risk factors for trichosporonosis. Urinary tract infections were the most common clinical presentation, particularly among male and elderly patients. Mortality rates were high, especially among older individuals.

Conclusion

This study contributes valuable epidemiological insights into trichosporonosis, highlighting the need for enhanced surveillance and preventive strategies in healthcare settings. Further research is warranted to optimize treatment approaches and infection control measures, ultimately reducing the burden of Trichosporon infections on patient outcomes.

Characteristics of fungi formation in urban sewer at different flow conditions: Distribution, metabolism, and pathogenicity

Fungi are the significant components of the sewer ecology system which can consume substances and exhibit pathogenicity. However, the characteristics of fungi formation and metabolism in the complex sewer environment have not been revealed in depth. In this study, gradient flow conditions were conducted in a pilot sewer and the formation characteristics of fungi were synthetically investigated. The results showed that the low flow rate at 0.1-0.4 m/s led to the loose morphology of biofilms, while the overly loose environment did not allow fungi communities to thrive in sewer. The dense biofilms were found at the middle flow condition (0.4-0.6 m/s), and the fungal communities with degradation functions were exuberant at this condition (such as Tremellales with relative abundance of 6.18% and Talaromyces with relative abundance of 6.51%). In particular, eleven kinds of fungi with known pathogenicity of the sewer biofilm were found in this study, and it is worth noting that the abundance of pathogenic fungi at medium flow rates is significantly higher than that at other flow conditions (higher than 10 %). While, excessive flow shear force (0.8-1.2 m/s) led to biofilm shedding which caused hindering the proper generation of fungi. In summary, the pollutant transformation and pathogenic exposure conducted by fungi communities could affect the sewer management process significantly, and this study could provide research foundation for wastewater quality prediction and management of pathogenic risk in sewer systems.

Isolation of Hexavalent chromium tolerant fungal species from urban vegetable farm soil and effluent waste in Addis Ababa& Rift valley, Ethiopia

Hexavalent chromium is resistant to degradation and harmful toxic substance to environment and community health. Physicochemical treatment methods are demanding high cost, used large quantities of chemicals & energy, release large amount of secondary toxic degradants. Mycoremediation is an eco-friendly alternative treatment method. The main objective of this research is to isolate and characterize chrome (VI) tolerant fungi from farm soil & industry effluent for mycoremedation purpose. The screening and isolation of yeast was carried out on potato dextrose agar media. PDA and broth assay test for fungi tolerance to hexavalent chromium at different concentration, temperature and pH was evaluated. Fungi species was identified biochemically using Biolog Microstation depending on carbon utilization and chemical sensitivity test. The result revealed that 10 yeast species was identified with full ID from effluent waste and farm soil based on their probability ≥  75% and similarity index ≥  0.5 as well as their Cr (VI) tolerance ability up to 2500 ppm. These are Yarrowia lipolytica (100%, 0.7), Cryptococcus luteolus(100%, 0.64), Rhodotorula aurantiaca A(100%, 0.62), Ustilago maydis(100%, 0.58) Trichosporon beigelii B (100%, 0.51), Cryptococcus terreus A (100%, 0.62), Zygosaccharomyces bailii (98%, 0.65), Nadsoniafulvenscens (90%, 0.62), Schizoblastosporonstarkeyihenricii (89%, 0.56), Endomycopsis vivi (84%, 0.62), Rhodotorula pustula (Sim, 0.59). Two yeast species Yarrowia lipolytica and Nadsoniafulvenscens show the highest growth mean Optical density (OD) measure 0.74 ± 0.2 & 0.60 ± 0.2 respectively at pH 7 & 25 °C. The highest tolerance index (mm) was recorded by Schizoblastosporon starkey henricii 0.3067 ± 0.152. Cr (VI)-tolerance ability of these yeast strains used in the development of chromium-bioremediation technologies provide an alternative option for chromium sequestration after HPLC analysis& molecular characterization.

Invasive Trichosporonosis in Neonates and Pediatric Patients with Malignancies or Hematologic Disorders

(1) Background: Trichosporon species have emerged as important opportunistic fungal pathogens, with Trichosporon asahii being the leading and most frequent cause of invasive disease. (2) Methods: We performed a global review focused on invasive trichosporonosis in neonates and pediatric patients with malignancies or hematologic disorders. We reviewed case reports and case series of trichosporonosis due to T. asahii published since 1994, the year of the revised taxonomic classification. (3) Results: Twenty-four cases of invasive trichosporonosis were identified in neonates with the presence of central venous catheter and use of broad-spectrum antibiotics recognized as the main predisposing factors. Thirty-two cases were identified in children with malignancies or hematologic disorders, predominantly with severe neutropenia. Trichosporon asahii was isolated from blood in 24/32 (75%) pediatric cases. Cutaneous involvement was frequently observed in invasive trichosporonosis. Micafungin was the most commonly used prophylactic agent (9/22; 41%). Ten patients receiving prophylactic echinocandins were identified with breakthrough infections. A favorable outcome was reported in 12/16 (75%) pediatric patients receiving targeted monotherapy with voriconazole or combined with liposomal amphotericin B. Overall mortality in neonates and children with malignancy was 67% and 60%, respectively. (4) Conclusions: Voriconazole is advocated for the treatment of invasive trichosporonosis given the intrinsic resistance to echinocandins and poor susceptibility to polyenes.

Trichosporon Species and Fusarium Species as a Cause of Empyema Thoracis in a Diabetic Patient

Of late, fungal infections are increasingly being recognized in diabetic patients. Here we present a case of polymicrobial fungal empyema due to Trichosporon species and Fusarium species developed after community-acquired pneumonia in a diabetic patient. Trichosporon species are basidiomycetous yeast and Fusarium species are soil saprophytes with a worldwide distribution. Fungal empyema cases are rare and are mostly caused by Aspergillus and Candida species. Polymicrobial fungal empyema with Trichosporon species and Fusarium species has not been reported previously. Our patient was successfully treated with antifungal therapy. This case highlights that fungal empyema should be considered in diabetic patients especially if they are not responding to antibiotics.

Oxyresveratrol-induced DNA cleavage triggers apoptotic response in Candida albicans

Oxyresveratrol is a naturally occurring phytoalexin produced by plants in response to infection. Biological activities of oxyresveratrol have been studied such as antioxidant, anticancer and anti-inflammation. However, further antimicrobial activity and its mechanism need to be investigated. This study exhibited growth inhibition against pathogenic fungi and investigated its mode of action. Oxyresveratrol inflicted cleavage on DNA, leading to G2/M phase arrest. DNA damage by oxyresveratrol was not the result of oxidative stress but it was triggered by direct binding to DNA. Oxyresveratrol-treated cells showed an apoptotic pathway characterized by phosphatidylserine exposure, apoptotic volume decrease and metacaspase activation. Mitochondria-associated apoptotic features also appeared. Oxyresveratrol-induced Ca²⁺ overload led to mitochondrial membrane depolarization and release of cytochrome c from mitochondria to cytosol. In conclusion, oxyresveratrol with DNA-binding affinity induces DNA cleavage, and eventually leads to mitochondria-mediated apoptosis in Candida albicans.

Molecular and antifungal susceptibility study on trichosporonemia and emergence of Trichosporon mycotoxinivorans as a bloodstream pathogen

A total of 21 Trichosporon spp. isolates from blood over a period of 5 years (January 2009 to December 2013) were included in the study. The most common underlying diseases found were pancreatitis (33.3%) and cancer (33.3%). Trichosporon asahii (80.9%) was the commonest species followed by Trichosporon mycotoxinivorans (14.2%) and Trichosporon faecale (4.7%). On IGS1 region sequencing the most predominant T. asahii type in our region was genotype 1 (16/17 isolates; 94.1%) and one isolate belonged to genotype 4. Following the interpretative breakpoints for Candida albicans according to CLSI guidelines amphotericin B minimum inhibitory concentrations (MICs) were ≤1 μg/ml for 38% of isolates. Fluconazole MICs were ≤4 μg/ml for 33.3% of the isolates. Itraconazole MICs were ≤0.5 μg/ml for 52.3% of the isolates. However, the MICs to posaconazole and voriconazole were ≤0.5 μg/ml for all the isolates. The MICs to caspofungin and micafungin were ≤0.5 μg/ml for only 0.09% of the isolates. This study reemphasizes that IGS1 sequencing is the most reliable technique for accurate identification of Trichosporon spp. and also to identify the newer species like T. mycotoxinivorans, which still remains rare. Surveillance of antifungal susceptibility patterns can provide the local drug resistance data to the clinicians which can further aid better management of patients.

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.

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.

Detection and characterization of plasminogen receptors on clinical isolates of Trichosporon asahii

Trichosporon asahii is the major causative agent of deep-seated trichosporonosis. The virulence factors of this yeast pathogen remain uncharacterized. To investigate the pathogenicity of T. asahii, we focused on the interactions between surface molecules of the yeast and host biomolecules. We examined the ability of surface molecules to bind human plasminogen using clinical isolates of T. asahii. Living T. asahii cells accelerated the conversion of plasminogen to plasmin in a dose-dependent manner in the presence of tissue plasminogen activator. Extracts from cells using lithium chloride contained plasminogen-binding molecules based on surface plasmon resonance (SPR) analyses. In all strains tested, several of the fractions obtained using DEAE column chromatography bound and accelerated the conversion of plasminogen to plasmin. Based on far-Western blotting analyses, a common protein was identified within the four strains, which was identified as a hypothetical protein from genome analyses of T. asahii. blast searches suggested the protein might be heparinase, and heparinase activity was detected in the T. asahii extract. Furthermore, affinity chromatography using plasminogen as a ligand detected one protein band by SDS-PAGE, which was identified as thioredoxin-dependent peroxide reductase.SPR analyses suggested the presence of molecules on T. asahii cells that could bind plasminogen with differing affinities.

Invasive trichosporonosis in an AIDS patient: case report and review of the literature

Invasive Trichosporon infection is a rare, life-threatening infection in immunocompromised patients. It has been reported as an emerging opportunistic infection in those with acquired immune deficiency syndrome (AIDS). Only 12 cases of invasive trichosporonosis in patients with HIV have been documented, none in Southeast Asia. We report a case of fatal, disseminated trichosporonosis in a Filipino AIDS patient with severe cutaneous and pulmonary involvement. Invasive trichosporonosis should be considered in HIV-positive patients with disseminated fungal infection since this may be refractory to conventional antifungal treatment.

Development of a peptide nucleic acid probe to Trichosporon species and identification of trichosporonosis by use of in situ hybridization in formalin-fixed and paraffin-embedded (FFPE) sections

In order to identify Trichosporon species in formalin-fixed and paraffin-embedded sections from which visual discrimination of non-glabrata Candida species is mostly ineffective but critical for the choice of antifungals, we tested the usefulness of a newly designed peptide nucleic acid probe (PNA) for in situ hybridization (ISH). Results confirmed the usefulness of ISH with our PNA probe in identifying Trichosporon species from Candida albicans.

Current knowledge of Trichosporon spp. and Trichosporonosis

Trichosporon spp. are basidiomycetous yeast-like fungi found widely in nature. Clinical isolates are generally related to superficial infections. However, this fungus has been recognized as an opportunistic agent of invasive infections, mostly in cancer patients and those exposed to invasive medical procedures. It is possible that the ability of Trichosporon strains to form biofilms on implanted devices, the presence of glucuronoxylomannan in their cell walls, and the ability to produce proteases and lipases are all factors likely related to the virulence of this genus and therefore may account for the progress of invasive trichosporonosis. Disseminated trichosporonosis has been increasingly reported worldwide and represents a challenge for both diagnosis and species identification. Phenotypic identification methods are useful for Trichosporon sp. screening, but only molecular methods, such as IGS region sequencing, allow the complete identification of Trichosporon isolates at the species level. Methods for the diagnosis of invasive trichosporonosis include PCR-based methods, Luminex xMAP technology, and, more recently, proteomics. Treating patients with trichosporonosis remains a challenge because of limited data on the in vitro and in vivo activities of antifungal drugs against clinically relevant species of the genus. Despite the mentioned limitations, the use of antifungal regimens containing triazoles appears to be the best therapeutic approach.

Disseminated trichosporonosis in a burn patient: meningitis and cerebral abscess due to Trichosporon asahii

A 44-year-old diabetic female presented to a hospital in Jamaica with thermal burns. Trichosporon asahii was isolated from facial wounds, sputum, and a meningeal swab. Dissemination of the fungus was demonstrated in stained histological sections of the meninges and a brain abscess at autopsy. Pure growth of the fungus from patient samples submitted and an environmental isolate obtained from a wash basin in the hospital supported the diagnosis.

Successful treatment of Trichosporon fungemia in a patient with refractory acute myeloid leukemia using voriconazole combined with liposomal amphotericin B

Trichosporon fungemia is a rare and fatal fungal infection that occurs in patients with prolonged neutropenia associated with hematologic malignancies. A 21-year-old male developed Trichosporon fungemia during remission induction therapy for acute myeloid leukemia (AML). Although two courses of induction therapy failed to induce a remission of AML, combination therapy with voriconazole and liposomal amphotericin B (L-AmB) followed by monocyte colony-stimulating factor ameliorated the Trichosporon fungemia and enabled the patient to receive reduced-intensity bone marrow transplantation (BMT) from his human leukocyte antigen-A one-locus mismatched mother. The patient achieved a durable remission after BMT without exacerbation of Trichosporon fungemia. The combination therapy with voriconazole and L-AmB may therefore be useful in controlling Trichosporon fungemia associated with prolonged neutropenia after remission induction therapy for AML.

A case of endogenous trichosporon endophthalmitis treated with micafungin and voriconazole

Invasive fungal infections are a significant cause of morbidity and mortality. Endogenous fungal endophthalmitis is a rare intraocular infection with potential vision threatening consequences. Our review of the literature revealed only one other case of Trichosporon endophthalmitis. Ocular fungal infections are difficult to eradicate because of the limited availability of systemic and intravitreal therapeutic agents and poor tissue penetration of current antifungals. Along with systemic antifungal agents, vitrectomy and intravitreal amphotericin B have been suggested as optimal treatments for fungal endophthalmitis. Other antifungals such as flucytosine and triazoles have recently received consideration. Although the current antifungal therapy is not highly successful, there remains a significant potential for more successful treatments in the future, based on the current studies. We report a case of endogenous trichosporon endophthalmitis that was successfully treated with micafungin and voriconazole. This combination has not been previously reported as a successful therapy in literature. More targeted research is required to uncover additional efficacious therapies to combat trichosporon.

Differential diagnosis of trichosporonosis using conventional histopathological stains and electron microscopy

AIMS

Although Trichosporon is a causative pathogen of white piedra and summer-type hypersensitivity pneumonitis, fatal disseminated trichosporonosis cases have recently been increasing. However, Trichosporon is often confused with other fungi, especially Candida, in pathological specimens. The aim was to determine the utility of histopathological stains and electron microscopy for diagnosing trichosporonosis.

METHODS AND RESULTS

Autopsy cases of trichosporonosis, candidiasis, aspergillosis and cryptococcosis were investigated using histopathological stains and electron microscopy. Using Grocott's method, Trichosporon was weakly detected compared with other fungi. In contrast, diluted periodic acid methenamine silver (PAM) stain clearly enhanced the intensity of staining of Trichosporon compared with Candida. Furthermore, Alcian blue and colloidal iron stains predominantly detected Trichosporon. Electron microscopy after staining with diluted PAM demonstrated that Trichosporon has a variety of hyphal sizes and laminar deposition of rough silver granules, whereas Candida has uniform pseudohyphae and fine granules. The average diameter and population area of the granules were significantly higher in Trichosporon compared with Candida (P<0.01). Meanwhile, the laminar structure was preserved in the cell walls of Trichosporon without silver stains, whereas a low-density structure was observed in Candida.

CONCLUSIONS

Histopathological staining patterns and electron microscopic findings can facilitate the diagnosis of trichosporonosis.

Epidemiology of invasive mycoses in North America

The incidence of invasive mycoses is increasing, especially among patients who are immunocompromised or hospitalized with serious underlying diseases. Such infections may be broken into two broad categories: opportunistic and endemic. The most important agents of the opportunistic mycoses are Candida spp., Cryptococcus neoformans, Pneumocystis jirovecii, and Aspergillus spp. (although the list of potential pathogens is ever expanding); while the most commonly encountered endemic mycoses are due to Histoplasma capsulatum, Coccidioides immitis/posadasii, and Blastomyces dermatitidis. This review discusses the epidemiologic profiles of these invasive mycoses in North America, as well as risk factors for infection, and the pathogens' antifungal susceptibility.

Trichosporon mycotoxinivorans, a novel respiratory pathogen in patients with cystic fibrosis

This report describes the molecular epidemiology, in vitro susceptibility, colonial and microscopic morphologies, and biochemical features of Trichosporon mycotoxinivorans, a newly recognized pathogen that appears to have a propensity for patients with cystic fibrosis. The index patient died with histologically documented Trichosporon pneumonia complicating cystic fibrosis. This is also the first report of disease caused by a Trichosporon species in a nontransplant patient with cystic fibrosis. As T. mycotoxinivorans has not previously been recognized as a respiratory pathogen, the significance of its recovery from sputum samples was not initially appreciated. Genetic analysis of archived clinical samples found three additional cases of T. mycotoxinivorans infection which had previously been identified as other members of the genus. An additional isolate of T. mycotoxinivorans was identified from a clinical sample on initial testing. Three of these four cases were also patients with cystic fibrosis. All isolates had MICs at 48 h of amphotericin B of > or = 1 microg/ml and of echinocandins of > or = 16 microg/ml, but they displayed various susceptibilities to the triazoles. In summary, Trichosporon mycotoxinivorans is a newly recognized human pathogen that is associated with cystic fibrosis.

Trichosporonosis in a tertiary care cancer center: Risk factors, changing spectrum and determinants of outcome

To assess the spectrum and outcome of trichosporonosis (TS) in cancer patients, we reviewed the medical records of 17 such patients with TS. TS presented most commonly as fungemia (n = 10, including 7 with central-venous-catheter-related infection) and either pulmonary or soft tissue infection (n = 3, each). Most patients (65%) had acute leukemia, 11 (65%) had neutropenia, and 9 (53%) had received high doses of corticosteroids. 10 patients had breakthrough TS during therapy with at least 1 of the following: amphotericin B, fluconazole, itraconazole, and voriconazole. The 30-d crude mortality rate was 53%. Predictors of mortality by using univariate analysis included: high median APACHE II score (p < 0.01), use of high dose of corticosteroids (p = 0.01), and admission to the intensive care unit (p < 0.01). TS is associated with a high mortality rate in cancer patients. The spectrum of infection at our institution has shifted from a predominance of disseminated infection to CVC-related fungemias without evidence of tissue invasion.

Rhodotorula spp. isolated from blood cultures: clinical and microbiological aspects

The emergence of less common fungal pathogens has been increasingly reported in the last decade. We describe 25 cases of Rhodotorula spp. isolated from blood cultures at a large Brazilian tertiary teaching hospital from 1996-2004. We also investigated the in vitro activity of four antifungal drugs, using a standardized method. The median age of patients was 43 years. The majority of patients (88%) had a central venous catheter (CVC) and 10 (40%) were recipients of a bone marrow transplant. The episode was classified as a bloodstream infection (BSI) in 80% of the patients. Amphotericin B deoxycholate was the most common antifungal used and CVC was removed in 89.5% of the patients. Death occurred in four patients (17.4%), all classified as BSI. All strains were identified as R. mucilaginosa by conventional methods. Misidentification of the species was observed in 20% and 5% of the strains with the Vitek Yeast Biochemical Card and API 20C AUX systems, respectively. Amphotericin B demonstrated good in vitro activity (MIC50/90, 0.5 microg/ml) and the MICs for fluconazole were high for all strains (MIC50/90, >64 microg/ml).

Early detection of breakthrough trichosporonosis by serum PCR in a cord blood transplant recipient being prophylactically treated with voriconazole

An 18-year-old man with myelodysplastic syndrome after stem-cell transplantation developed breakthrough trichosporonosis while being administered voriconazole, a broad-spectrum triazole. Importantly, Trichosporon was detected soon after infection by a screening serum polymerase chain reaction test, but not by blood culture. This case illustrates that the serum polymerase chain reaction assay might be effective for early detection of fungemia in immunocompromised patients, including recipients of stem-cell transplants undergoing prophylactic antifungal therapy using voriconazole, which cannot be assumed to always provide complete protection against Trichosporon infection.

Quantitative PCR assay used to monitor serum Trichosporon asahii DNA concentrations in disseminated trichosporonosis

A bone marrow transplant recipient with disseminated trichosporonosis was successfully treated with voriconazole. Quantitative PCR assay results for Trichosporon asahii DNA in the sera were well correlated with the patient's clinical course. Based on the in vitro susceptibility test, the organism was susceptible to voriconazole.

Supplemental utility of nested PCR for the pathological diagnosis of disseminated trichosporonosis

Disseminated trichosporonosis is known to be a severe opportunistic mycosis and has a high mortality rate. In autopsy cases, it is often difficult to diagnose as trichosporonosis because the causative Trichosporon species are pathologically similar to other fungi, especially the Candida species. Immunohistochemical analysis is essential for the differential diagnosis, but an antibody to Trichosporon is not available commercially. In the present study, we investigated the supplemental utility of nested polymerase chain reaction (PCR) for the pathological diagnosis of trichosporonosis from formalin-fixed and paraffin-embedded tissues. Total DNA was purified from 30 major organs in three autopsy cases, and Trichosporon DNA was specifically amplified by nested PCR using three sets of primers. Of 22 organs in which Grocott's stain was positive for fungal infection, 170- and 259-bp PCR products were detected in 20 (91%) and 12 (55%) organs, respectively. In short-term fixation (about 1 day), these bands were highly detected in ten (100%) and nine (90%) organs, whereas the detection efficiency tended to decrease after long-term fixation and decalcification. No PCR product of 412 bp was detected in any organs. These findings suggest that nested PCR from short-term-fixed tissues is useful for supportive pathological diagnosis of disseminated trichosporonosis.

Sternal wound infection by Trichosporon inkin following cardiac surgery

Wound infection following cardiac surgery is well described but is rarely due to fungal infection. We describe a case of sternal wound infection caused by Trichosporon inkin with a fatal outcome, in an immunocompetent patient following aortic root surgery.

Successful Treatment of Breakthrough Trichosporon asahii Fungemia with Voriconazole in a Patient with Acute Myeloid Leukemia

We describe a 55-year-old man with acute myelogenous leukemia who developed breakthrough Trichosporon asahii fungemia during 5 days of micafungin treatment. Although the patient's clinical condition improved considerably after the start of voriconazole treatment, blood culture results remained positive for T. asahii for 3 days, and fever persisted for 7 days thereafter. The patient achieved complete hematological remission, and he received successful consolidation chemotherapy without developing Trichosporon infection with the prophylactic use of voriconazole therapy. This case report illustrates that voriconazole may be useful in the treatment of disseminated T. asahii infection in neutropenic patients.

Biological activity of Tat (47–58) peptide on human pathogenic fungi

Tat (47-58) peptide, a positively charged Arginine-rich peptide derived from HIV-1 regulatory protein Tat, is known for a peptidic delivery factor as a cell-penetrating peptide on mammalian cells. In this study, antifungal effect and its mode of action of Tat peptide were investigated on fungal cells. The results indicate that Tat peptide exhibits antifungal activity against pathogenic fungal cells without hemolytic effect on human erythrocytes. To understand the mechanism(s) of Tat peptide, the cellular distribution of the peptide was investigated. Tat peptide internalized in the fungal cells without any damage to cell membrane when examined using an artificial liposome (PC/cholesterol; 10:1, w/w). Moreover, flow cytometry analysis exhibited the uptake of Tat peptide by energy- and salt-independent pathway, and confocal scanning microscopy displayed that this peptide accumulated in the nucleus of fungal cells rapidly without any impediment by time or temperature, which generally influence on the viral infections. After penetration into the nuclear, the peptide affected the process of cell cycle of Candida albicans through the arrest at G1 phase.

Breakthrough Trichosporonosis in Patients with Hematologic Malignancies Receiving Micafungin

BACKGROUND

Micafungin is a newly approved antifungal agent in the echinocandin class that is active against Candida species and Aspergillus species. However, this agent has limited activity against a number of fungi, including Trichosporon species. We describe 4 patients who developed disseminated trichosporonosis during the use of micafungin. No cases of trichosporonosis had been seen in the 2 years prior to January 2003, when micafungin became available in our hospital.

METHODS

We reviewed microbiological records of patients at Kameda General Hospital (Kamogawa City, Chiba, Japan) from 1 January 2002 to 31 July 2005, and identified 4 patients whose blood culture results were positive for Trichosporon species.

RESULTS

Since January 2003, four patients--3 with acute myelocytic leukemia and 1 with myelodysplastic syndrome--developed disseminated trichosporonosis while receiving treatment with micafungin with or without amphotericin B. The initial 2 isolates were identified as Trichosporon beigelii, and the later 2 isolates were identified as Trichosporon asahii. All 4 patients received micafungin, and 2 also received amphotericin B concomitantly. Minimal inhibitory concentrations of micafungin were >16 microg/mL for the 2 isolates available for susceptibility testing. One patient with hematologic recovery (neutrophils >500 cells/mm3) showed elimination of the fungus after receiving treatment with voriconazole. However, the 3 other patients without hematologic or immunological recovery died of disseminated infection.

CONCLUSIONS

The rarity of trichosporonosis in our hospital and its emergence after the introduction of micafungin therapy support the idea that micafungin may exert a significant, selective pressure toward resistant fungi, such as Trichosporon species. Therefore, care should be taken regarding the possibility of trichosporonosis in patients receiving micafungin with or without amphotericin B.

Trichosporon asahii fatal infection in a non-neutropenic patient after orthotopic liver transplantation

Trichosporon asahii is a yeast that may cause systemic infection, especially in neutropenic patients. To our knowledge, only two cases of invasive infection with Trichosporon were previously described in liver transplant recipients. We describe an additional case of T. asahii infection after orthotopic liver transplantation in a non-neutropenic patient who had no known risk factor for invasive fungal infection, and died in spite of amphotericin B therapy.

Invasive infections caused by Trichosporon species and Geotrichum capitatum in patients with hematological malignancies: a retrospective multicenter study from Italy and review of the literature

Trichosporonosis is an uncommon but frequently fatal mycosis in immunocompromised patients. A multicenter retrospective study was conducted to characterize cases of proven or probable invasive trichosporonosis diagnosed over the past 20 years in Italian patients with hematological diseases. Of the 52 cases identified, 17 were classified as Trichosporon sp. infections and 35 were attributed to Geotrichum capitatum. Acute myeloid leukemia accounted for 65.4% of the cases. The incidence rates of Trichosporon sp. and G. capitatum infections in acute leukemia patients were 0.4 and 0.5%, respectively. Overall, 76.9% of cases had positive blood cultures. Pulmonary involvement was documented in 26.9% of cases. Death was reported for 57.1% of G. capitatum infections and for 64.7% of Trichosporon sp. infections. A literature review on trichosporonosis in patients with any underlying disease or condition reveals G. capitatum as a predominantly European pathogen, particularly in certain Mediterranean areas, while Trichosporon sp. infections are seen with similar frequencies on all continents. The majority of published Trichosporon sp. and G. capitatum infections occurred in patients with hematological diseases (62.8 and 91.7%, respectively). Well over half of these were suffering from acute leukemia (68 and 84% of patients with Trichosporon sp. and G. capitatum infections, respectively). Crude mortality rates were 77% for Trichosporon spp. and 55.7% for G. capitatum. The optimal therapy for trichosporonosis has yet to be identified; however, in vitro experiences are providing encouraging evidence of the potential role of the new triazoles, in particular, voriconazole.

Pulmonary fungal infection with yeasts and pneumocystis in patients with hematological malignancy

Invasive fungal infections are an important cause of morbidity and mortality in patients with hematological malignancies, and in particular fungal pneumonia is the main clinical manifestation in this category of patients. The fungal agents responsible for this complication are various, but Aspergillus spp. and other molds such as Zygomycetes or Fusarium spp. represent the most frequently isolated micro-organisms. Less commonly, pneumonia could be due to other 'no-molds' fungal agents such as Candida spp, Cryptococcus spp, or Pneumocystis jirovecii . This review mainly focuses on practical aspects relevant to epidemiology, diagnosis and therapeutic management of the rare cases of pneumonia due to no-molds agents in patients affected by hematological malignancies.

Infections due to emerging and uncommon medically important fungal pathogens

The emergence of less common but medically important fungal pathogens contributes to the rate of morbidity and mortality, especially in the increasingly expanding population of immunocompromised patients. These pathogens include septate filamentous fungi (e.g., Fusarium spp., Scedosporium spp., Trichoderma spp.), nonseptate Zygomycetes, the endemic dimorphic pathogen Penicillium marneffei, and non-Cryptococcus, non-Candida pathogenic yeast (e.g., Trichosporon spp.). The medical community is thus called upon to acquire an understanding of the microbiology, epidemiology and pathogenesis of these previously uncommon pathogens in order to become familiar with the options for prevention and treatment.

White piedra: further evidence of a synergistic infection

White piedra is a fungal infection of the hair shaft caused by Trichosporon beigelii. A synergistic coryneform bacterial infection is often present with T beigelii. White piedra, although not commonly reported to infect scalp hair in North America, is an important consideration in the differential diagnosis of scalp hair concretions. We report a case of white piedra of scalp hair with synergistic coryneform bacterial infection in two sisters, both US natives. Culture and light and electronmicroscopic evidence of the synergistic infection are presented.

Superficial mycotic infections of the foot in a native pediatric population: a pathogenic role for Trichosporon cutaneum?

Superficial mycotic infections of the feet are usually caused by Tricophyton rubrum, predominantly affecting adults and resulting from the use of occlusive footwear. We carried out a mycologic study of superficial foot infections in a rural school in Mexico where most people wear a leather, nonocclusive sandal. Forty students had clinical signs of 50 fungal infections of the foot: 39 athlete's foot and 11 onychomycosis. Thirty-one boys and 9 girls were studied. Hyphae were seen in 11 cases of athlete's foot and 5 of onychomycosis. Twenty-one cultures were positive (42%). The most frequently isolated fungi were the opportunistic Trichosporon cutaneum in 42.8%, Candida sp. (23.8%), Trichophyton mentagrophytes (23.8%), and Candida glabrata (9.5%). Superficial mycotic infections of the feet and nails were most frequent in children and adolescents who usually wear nonocclusive shoes. The most frequent pathogens were Candida sp. and T. mentagrophytes. It is interesting to note the prevalence of T. cutaneum that has recently been implicated in mycoses of the feet and nails. We did not isolate T. rubrum in any patient.

Trichosporon pullulans infection in 2 patients with chronic granulomatous disease: an emerging pathogen and review of the literature

BACKGROUND

Chronic granulomatous disease is a genetically determined primary immunodeficiency disease in which phagocytic cells are unable to kill certain bacteria and fungi after ingestion. Manifestations include recurrent pyogenic infections caused by catalase-positive microbes. Trichosporon species are emerging as opportunistic agents that cause systemic disease in immunocompromised patients. Typically disease has been described in association with T beigelii in patients with secondary immunodeficiency, such as underlying malignancy.

OBJECTIVE

The objective was to report the first 2 cases of T pullulans infection in 2 male children with chronic granulomatous disease.

METHODS

The records of the 2 patients were reviewed. In addition, all cases of T pullulans infection reported in the English language literature are presented.

RESULTS

This report brings to 7 the total number of cases of T pullulans reported and the first in patients with chronic granulomatous disease, one with invasive pneumonia and the other with an infected paronychium and localized cellulitis. In the 5 additional cases malignancy was the principal risk factor.

CONCLUSION

T pullulans has rarely been reported as a fungal pathogen. The most prominent risk factor for the development of trichosporonosis is immunocompromise, most notably with neutropenia. Abnormally functioning neutrophils, such as with chronic granulomatous disease, may also predispose individuals to this opportunistic pathogen.