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

A novel report on the emerging and zoonotic neurotropic fungus Trichosporon japonicum in the brain tissue of the endangered Brazilian guitarfish (Pseudobatos horkelii) off the southeastern coast of Brazil

Yeast infections have gained significant attention in the field of marine biology in recent years. Among the broad diversity of marine organisms affected by these infections, elasmobranchs (sharks and rays) have emerged as highly susceptible, due to climate change effects, such as increasing water temperatures and pollution, which can alter the composition and abundance of fungal communities. Additionally, injuries, or compromised immune systems resulting from pollution or disease may increase the likelihood of fungal infections in elasmobranchs. Studies are, however, still lacking for this taxonomic group. In this context, this study aimed to screen yeast species in cell cultures obtained from the brain of artisanally captured Pseudobatos horkelii, a cartilaginous fish that, although endangered, is highly captured and consumed worldwide. Fungi were isolated during an attempt to establish primary cultures of elasmobranch neural cells. Culture flasks were swabbed and investigated using morphological, phenotypic, and molecular techniques. Two isolates of the emerging opportunistic pathogen Trichosporon japonicum were identified, with high scores (1.80 and 1.85, respectively) by the MALDI-ToF technique. This is the first report of the basidiomycetous yeast T. japonicum in Pseudobatos horkelii in Brazil. This finding highlights the need for further research to determine the potential impact on elasmobranch health, ecology, as well as on commercial fisheries.

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.

Heterologous extracellular DNA facilitates the development of Trichosporon asahii and T. inkin biofilms and enhances their tolerance to antifungals

Trichosporon asahii and T. inkin are emergent agents of deep-seated and disseminated infections in immunocompromised patients. The present study aimed to investigate the role of extracellular DNA (eDNA) and the enzyme deoxyribonuclease (DNase) on the structure of T. asahii and T. inkin biofilms, as well as to examine their effect on the susceptibility to antifungals. Biofilms reached maturity at 48 h; eDNA concentration in the supernatant increased over time (6 < 24 h < 48h). Exogenous eDNA increased biomass of Trichosporon biofilms at all stages of development, enhanced their tolerance to antifungals and improved their structural complexity. DNase reduced biomass, biovolume and thickness of Trichosporon biofilms, thereby rendering them more susceptibility to voriconazole. The results suggest the relevance of eDNA in the structure and antifungal susceptibility of Trichosporon biofilms and highlight the potential of DNase as adjuvant in biofilm control.

Pericardial Effusion Due to Trichosporon japonicum: A Case Report and Review of the Literature

Invasive infections due to Trichosporon spp. are life-threatening opportunistic fungal infections that may affect a wide array of organs. Here, we described a case of pericardial effusion due to Trichosporon japonicum in a 42-year-old female after a heart transplantation. T. japonicum was isolated from the pericardial fluid, pericardial drain hole and the swab of the sternal surgery scar wound. The late mycological diagnosis due to blood culture negative, the ineffective control of pulmonary bacterial infection and the late start antifungal therapy were the contributing factors in the patient’s death.

Trichosporon asahii causing subcutaneous mycoses in an immunocompetent patient: case report and a minireview

Trichosporon spp. are a constituent of the normal flora of humans that can cause both superficial and invasive infections, mainly in immunocompromised and immunocompetent hosts, respectively. Herein, we a report of Trichosporon asahii causing subcutaneous fungal infection (SFI) in an immunocompetent patient after carpal tunnel surgery. Although susceptible to fluconazole, the treatment of SFI failed even using high doses of this azole. The skin lesion improved following the administration of voriconazole. We conducted a literature minireview searching reports on SFI in immunocompetent patients to check for epidemiological, diagnostic, therapeutic, and outcome characteristics. A total of 32 cases were reported. Despite being uncommon, the clinical suspicion and early diagnosis of SFI in immunocompetent patients undergoing previous surgery are important. Our study indicated that the azoles are the most active antifungal agents against Trichosporon spp., except for fluconazole, and voriconazole can be considered the first therapeutic option.

Case Report: Trichosporon japonicum Fungemia in a Pediatric Patient With Refractory Acute B Cell Lymphoblastic Leukemia

Trichosporon japonicum is a very rare opportunistic yeast causing fungal disease in humans, especially in immunocompromised hosts. Here, we describe a new case of T. japonicum isolated from the blood of a pyrexial pediatric patient with refractory acute B cell lymphoblastic leukemia and acute respiratory distress. Prompt diagnosis through early clinical suspicion and appropriate molecular microbiology analysis allowed the yeast to be accurately identified at species level. Subsequent drug susceptibility testing and focused antifungal treatment with voriconazole and amphotericin B led to a complete clinical and mycological resolution of the infection, which represents the second successful case of T. japonicum bloodstream infection described in literature to date.

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.

Contemporary Management Strategies in VAD Infection

PURPOSE OF REVIEW

The use of durable ventricular assist devices (VAD) to manage end-stage heart failure is increasing, but infection remains a leading cause of morbidity and mortality among patients with VAD. In this review, we synthesize recent data pertaining to the epidemiology, diagnosis, management, and prevention of VAD infections, discuss transplant considerations in patients with VAD infections, and highlight remaining knowledge gaps. We also present a conceptual framework for treating clinicians to approach these infections that draws on the same principles that guide the treatment of analogous infections that occur in patients without VAD.

RECENT FINDINGS

Despite advances in device design, surgical techniques, and preventative interventions, more than a third of VAD recipients still experience infection as an adverse outcome. Positron emission tomography has emerged as a promising modality for identifying and characterizing VAD infections. High-quality data to support many of the routine therapeutic strategies currently used for VAD infections-including suppressive antibiotic therapy, surgical debridement/device exchange, and novel antimicrobials for emerging multidrug-resistant organisms-remain limited. Although pre-transplant VAD infection may impact some early transplant outcomes, transplantation remains a viable option for patients with most types of VAD infection. Standardized definitions of VAD infection applied to large registry datasets have yielded key insights into the epidemiology of infectious complications among VAD recipients, but more prospective studies are needed to evaluate the effectiveness of existing and novel diagnostic and therapeutic strategies.

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.