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

Trichosporon asahii is an emerging opportunistic pathogen that causes potentially fatal disseminated trichosporonosis. The global prevalence of coronavirus disease 2019 (COVID-19) poses an increasing fungal infection burden caused by T. asahii. Allicin is the main biologically active component with broad-spectrum antimicrobial activity in garlic. In this study, we performed an in-depth analysis of the antifungal characteristics of allicin against T. asahii based on physiological, cytological, and transcriptomic assessments. In vitro, allicin inhibited the growth of T. asahii planktonic cells and biofilm cells significantly. In vivo, allicin improved the mean survival time of mice with systemic trichosporonosis and reduced tissue fungal burden. Electron microscopy observations clearly demonstrated damage to T. asahii cell morphology and ultrastructure caused by allicin. Furthermore, allicin increased intracellular reactive oxygen species (ROS) accumulation, leading to oxidative stress damage in T. asahii cells. Transcriptome analysis showed that allicin treatment disturbed the biosynthesis of cell membrane and cell wall, glucose catabolism, and oxidative stress. The overexpression of multiple antioxidant enzymes and transporters may also place an additional burden on cells, causing them to collapse. Our findings shed new light on the potential of allicin as an alternative treatment strategy for trichosporonosis. IMPORTANCE Systemic infection caused by T. asahii has recently been recognized as an important cause of mortality in hospitalized COVID-19 patients. Invasive trichosporonosis remains a significant challenge for clinicians, due to the limited therapeutic options. The present work suggests that allicin holds great potential as a therapeutic candidate for T. asahii infection. Allicin demonstrated potent in vitro antifungal activity and potential in vivo protective effects. In addition, transcriptome sequencing provided valuable insights into the antifungal effects of allicin.

Invasive fungal infections in COVID-19 patients from Pakistan

Objective: The objective of this study is to report the frequency and clinical characteristic of IFI in COVID-19 patients. Method(s): This observational study was conducted in Karachi, Pakistan from March 2020-April 2021. Patients with COVID-19 associated aspergillosis (CAPA) were diagnosed using ECMM/ISHAM criteria modified to include tracheal aspirate culture and/or Galactomannan Index (GMI) >4.5 in the possible CAPA category. COVID-19 associated candidemia (CAC) was defined by isolation of Candida species from blood cultures. COVID-19 associated mucormycosis (CAM) was defined as updated EORTC/MSG criteria with inclusion of COVID-19 as host factor. Pneumocystis jirovecii pneumonia (PJP) was defined by consistent clinical and radiological features and PCR positivity. Result(s): During the study period a total of 123 (3.3%) IFI in 3506 hospitalized COVID-19 patients were identified. This included 78 (2.2%) CAPA patients (42 probable;36 possible), 29 (0.8%) CAC (5 C. auris;24 non-C. auris), 10 (0.3%) CAM (7 pulmonary;3 rhinocerebral), 3 (0.08%) PJP and three (0.08%) cases of rare invasive fungal infections (2 C. neoformans;1 Trichosporon asahii). Outcome data was available on 117/123 patients. Of these 117 patients, 78 expired (66.7%). These include 52/74 (70%) CAPA patients, 17/27 (63%) CAC patients, 7/10 (70%) CAM patients and 2/3 (67%) PJP patients. Conclusion(s): We report a rate of 3.3% IFI amongst hospitalized COVID-19 patients at our center. We consider this rate to be an underestimate due to less bronchoscopic procedures and inclusion of only candidemia cases. We also report higher mortality rate with IFI in our patients than global data probably due to delayed diagnosis, co-infections and limited therapeutic options.

A Case of Fatal Invasive Trichosporonosis in the Setting of Immunosuppression and Post-COVID-19 Pneumonia.

Trichosporon asahii is an opportunistic fungus that forms septate hyphae and pseudohyphae, resembling Candida albicans, and causes fungemia in susceptible individuals. Risk factors for T. asahii infection include immunosuppression, IV catheters, and malignancy. In the present case, a 67-year-old male with a history of renal transplant on immunosuppressive therapy was hospitalized for coronavirus disease 2019 (COVID-19) pneumonia. Despite treatment with steroids and broad initial antibiotic coverage with cefepime, doxycycline, and vancomycin, the patient underwent continual respiratory decline. His sputum culture on hospital day 10 was positive for non-candidal yeast, and despite subsequent appropriate empiric coverage with micafungin and amphotericin B, the patient continued to decline and ultimately died due to the resistance of T. asahii to these antifungals. This case highlights the importance of suspecting T. asahii as an infectious cause in patients whose cultures show non-candidal yeast and initiating appropriate antifungal treatment early in their treatment course.

White piedra: An uncommon cause of pseudonits in Northeast Mexico

Introduction: White piedra is a rare superficial mycosis caused by the genus Trichosporon. Its prevalence is higher among tropical climates and predominantly affects children and women. Less than 17 cases have been described in Mexico, none of them in the Northeast region. We present the first case reported in this zone. Case presentation: A 27-year-old otherwise healthy woman presented to our clinic with a 1-month history of asymptomatic pseudonits on her scalp hair. Physical evaluation revealed numerous small white concretions over the majority of the hair shafts. At trichoscopic inspection, multiple white-yellowish ovoid nodules were observed. Direct microscopic examination with 20% potassium hydroxide (KOH) and blue cotton showed nodules composed of arthroconidia and hyphae over the hair shaft. Additionally, fungal culture was positive for Trichosporon inkin, confirming the diagnosis of white piedra. Treatment was initiated with ketoconazole shampoo and systemic itraconazole with favorable response. Discussion(s): Since the first case description by Beigel in Germany, most white piedra cases have been reported in tropical and humid climates. This mycosis typically affects females and subjects under 15 years of age. Some risk factors include poor hygiene, excess humidity, diabetes, and long, curly hair. In our case, the patient had curly hair and she constantly tied her hair up wet as she worked as a full-time nurse in a COVID-19 reference center. In our country, 50% of previous reported cases are from nontropical regions. Although infrequent in cosmopolitan areas in Northeast Mexico, white piedra should be considered in the differential diagnosis of pseudonits. Copyright © 2022

Possible Trichosporon asahii urinary tract infection in a critically ill COVID-19 patient.

BACKGROUND: Trichosporon asahii, an emerging fungal pathogen, has been frequently associated with invasive infections in critically ill patients. CASE REPORT: A 74-year-old male patient diagnosed with COVID-19 was admitted to an Intensive Care Unit (ICU). During hospitalization, the patient displayed episodes of bacteremia by Staphylococcus haemolyticus and a possible urinary tract infection by T. asahii. While the bacterial infection was successfully treated using broad-spectrum antibiotics, the fungal infection in the urinary tract was unsuccessfully treated with anidulafungin and persisted until the patient died. CONCLUSIONS: With the evolving COVID-19 pandemic, invasive fungal infections have been increasingly reported, mainly after taking immunosuppressant drugs associated with long-term broad-spectrum antibiotic therapy. Although Candida and Aspergillus are still the most prevalent invasive fungi, T. asahii and other agents have emerged in critically ill patients. Therefore, a proper surveillance and diagnosing any fungal infection are paramount, particularly in COVID-19 immunocompromised populations.

Fungal Bloodstream Co-infection by Trichosporon asahii in a COVID-19 Critical Patient: Case Report and Literature Review.

Opportunistic infections are serious complications in critically ill COVID-19 patients, especially co-infections with bacterial and fungal agents. Here we report a rare case of bloodstream co-infection by Trichosporon asahii, an emerging yeast, and Acinetobacterbaumannii, an opportunistic nosocomial pathogen, both multidrug resistant, in a tertiary hospital from southern Brazil. A review of the literature regarding similar cases is also included. Treatment with multiple antimicrobials failed, and the patient progressed to death four days after the diagnosis of bacteremia and fungemia.

Demonstration of virulence factors of Trichosporon species isolated from clinical samples during the COVID 19 pandemic - A study from a tertiary care medical college hospital from South India

Background:Genus Tricosporon consists of basidiomycetous yeast that form a part of the human microbiota.They cause an array of human diseases, both in imunocompetant and immunocompromised patients. They are the second most commonly reported cause of disseminated infections in humans. Their ability to form Biofilms make them a potential agent of Catheter associated Fungemia. They exhibit virulence factors like Biofilm formation, hemolysis and produce enzymes like proteases and phospholipases that increases the pathogenicity by breaking down the proteins and dis- rupting the host cell membranes. The proteolytic activity plays an important role in its pathogenicity by facilitating inva- sion through degradation of keratin and collagen. Methods:This observational period study was performed at our hospital from 20/06/2020 to 20/10/2020.The isolates were subjected to tests to demonstrate virulence factors. Determination of phospholipase activity was performed using using egg yolk agar, hemolytic activity by SDA with 7% sheep blood, esterase activity was determined by using Tween -80 opacity test medium and the production of Biofilm formation was done by micro titre plate method. All results were recorded. The isolates were confirmed by MALDI TOF mass spectrometry. Results:1.Colony morphology 2.Urease production using christensons urea agar (2%) 3.Phenotypic and Biochemical test result were per- formed and tabulated. Proteomic confirmation results are awaited. [Formula presented] Conclusions:Knowing the virulence factor and the commonly occurring Trichosporon species aids in understanding the pathogenesis and to plan strategic treatment modalities

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 asahii fungemia and COVID-19 co-infection: An emerging fungal pathogen; case report and review of the literature.

With the evolving COVID-19 pandemic, increasing concerns about invasive fungal infections have been reported particularly with the use of potent immunosuppressant medications to treat the immunological storms in patients with severe COVID-19 illnesses. Trichosporon asahii (T. asahii) is an emerging highly resistant pathogen with considerable mortality particularly in critically ill patients and immunocompromised individuals. We describe a case of a 58-year-old patient who developed T. asahii fungemia after using immunosuppressant agents for his severe COVID-19 related cytokines release syndrome. Pseudohyphae, arthroconidia, and lateral blastoconidia were seen in the stain, and later confirmed to be T. asahii. Voriconazole successfully treated this multi-drug-resistant fungal infection. The clinical presentation, assessment, and management are reviewed to raise awareness of the circumstances leading to coinfection with this emerging resistant yeast.

Trichosporon asahii superinfections in critically ill COVID-19 patients overexposed to antimicrobials and corticosteroids.

OBJECTIVES: To investigate the occurrence of Trichosporon asahii fungemia among critically ill COVID-19 patients. METHODS: From 1 July to 30 September 2020, cases of T asahii fungemia (TAF) in a Brazilian COVID-19 referral centre were investigated. The epidemiology and clinical courses were detailed, along with a mycological investigation that included molecular species identification, haplotype diversity analysis and antifungal susceptibility testing. RESULTS: Five critically ill COVID-19 patients developed TAF in the period. All five patients had common risk conditions for TAF: central venous catheter at fungemia, previous exposure to broad-spectrum antibiotics, prior echinocandin therapy and previous prolonged corticosteroid therapy. The average time of intensive care unit hospitalisation previous to the TAF episode was 23 days. All but one patient had voriconazole therapy, and TAF 30-day mortality was 80%. The five T asahii strains from the COVID-19 patients belonged to 4 different haplotypes, mitigating the possibility of skin origin and cross-transmission linking the 5 reported episodes. The antifungal susceptibility testing revealed low minimal inhibitory concentrations for azole derivatives. CONCLUSIONS: Judicious prescription of antibiotics, corticosteroids and antifungals needs to be discussed in critically ill COVID-19 patients to prevent infections by hard-to-treat fungi like T asahii.