Medical mycology最新文献

The environmental niche and mode of transmission from the environment to humans of the emerging pathogenic yeast, Candidozyma (Candida) auris is a subject of speculation, with hypotheses including avian species and marine environments. Interestingly, yeasts related to Candidozyma auris have been repeatedly observed associated with various insects. This prompted us to investigate a thermophilic insect, Locustana pardalina, as a possible host for C. auris. Here, we report the isolation and identification of three C. auris strains from the gut of L. pardalina as well as the phenotypic characterisation of one of these isolates. Interestingly, the isolate was able to survive at 50°C and grew at 15% NaCl. In addition, it was susceptible to the tested disinfectants and antifungals, except fluconazole. Genome sequencing and single-nucleotide polymorphism analyses placed the isolate in Clade III, which is common in South African hospitals. This highlights the potential role of thermotolerant insects in the evolution and dissemination of emerging pathogenic yeasts.

Melanized fungi have occasionally been identified as causative agents of severe phaeohyphomycoses, chromoblastomycosis, and mycetoma. In a retrospective study conducted from January 2012 to December 2022, a total of 133 melanized fungi were isolated from hospitalized patients at the NIH Clinical Center, both with and without known underlying predisposing factors. Isolate identification was based on phenotypic characteristics, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-ToF MS), and PCR sequencing of the rDNA internal transcribed spacer (ITS) region. Members of the black yeast order Chaetothyriales were the most prevalent (40, 30%), predominantly Exophiala dermatitidis (30/40, 75%). Other major groups included: Capnodiales (30, 22.6%), Pleosporales (24, 18%), Mycosphaerellales (19, 14.3%), Calosphaeriales (8, 6%), and Venturiales (7, 5.3%). MALDI-ToF often failed to accurately identify the isolates, except for E. dermatitidis, which yielded scores ≥2. ITS sequencing was effective in accurately identifying the melanized fungi encountered in clinical settings. Antifungal susceptibility testing against eight antifungal agents showed that azoles, micafungin, and terbinafine exhibited in vitro activity against most isolates. In contrast, olorofim and amphotericin B were less effective. Notably, Phaeoacremonium species (Calosphaeriales) exhibited distinct antifungal susceptibility patterns. Accurate identification of melanized fungi in clinical laboratories is essential for selecting effective antifungal therapy, understanding susceptibility patterns to available agents, supporting epidemiological monitoring, and ultimately enhancing clinical outcomes in patients affected by these often complex and opportunistic infections.

Considering the need for a rapid, sensitive, and specific test for the early diagnosis of cryptococcal meningitis in critical regions where lumbar puncture and culture are inaccessible, we analyzed the specificity of the Lateral Flow Assay (LFA) for cryptococcal antigen in 217 serum specimens. Group 1: 68 Human Immunodeficiency Virus (HIV)-uninfected patients with paracoccidioidomycosis, histoplasmosis, aspergillosis, trichosporonosis, and tuberculosis; Group 2: 149 patients with HIV infection, including seven with histoplasmosis, and one with aspergillosis, and Group 3 with 24 proven cryptococcosis patients. Cross-reactivity of cryptococcal mannans and polysaccharides secreted by Paracoccidioides brasiliensis, Histoplasma capsulatum, and Trichosporon spp. has been described in vitro. However, only a few cases of positive LFA tests in aspergillosis, trichosporonosis, candidemia, and bacterial infections sera have been reported. We observed false-positive LFA in 2/29 aspergillosis specimens but not in other mycoses or tuberculosis. Among 149 HIV-infected patients, three specimens tested positive, two had cytomegalovirus infections, one of whom also had toxoplasmosis and the other, Kaposi´s sarcoma; one patient had no opportunistic infections. We observed sensitivities of 0.933 (serum), 0.95 (cerebrospinal fluid [CSF]), and 1.0 (serum or CSF) for LFA, and for all negative controls (N = 217, serum), a specificity of 0.977, and a negative predictive value (NPV) of 0.938. The specificity and NPV were 0.964 and 0.791, respectively, for 55 patients with mycoses; and 0.98 and 0.912 for 149 HIV-infected patients. We confirmed LFA's high specificity and accuracy for the control groups. There were 6.89% of false-positive results for aspergillosis, and no false-positive results for paracoccidioidomycosis, histoplasmosis, tuberculosis, or other bacterial diseases.

Vulvovaginal candidiasis (VVC), primarily caused by Candida albicans, affects a large proportion of women and often recurs due to drug resistance. This study investigates octyl gallate, a naturally derived compound, as a novel treatment for VVC in a mouse model. Female Bagg albino, laboratory-bred strain of the House Mouse (BALB/c) mice were infected with C. albicans and treated intravaginally with octyl gallate at low and high concentrations. Results demonstrated that octyl gallate significantly reduced fungal burden, restored beneficial Lactobacillus populations, and improved histological features of the vaginal tissue. Moreover, levels of pro-inflammatory cytokines, including interleukin (IL)-17A, IL-22, IL-23, and IL-1β, were markedly reduced, suggesting anti-inflammatory activity. No severe systemic side effects or hematological abnormalities were observed. These findings highlight the therapeutic potential of octyl gallate as a natural, dual-action agent for managing VVC through both antifungal and immunomodulatory effects. Further research is needed to evaluate its efficacy and safety in clinical settings.

To investigate the molecular mechanisms of Talaromyces marneffei (TM)-induced bone destruction through proteomic analysis using Data-Independent Acquisition (DIA) technology. Bone tissue samples were collected from eight patients (four TM-infected cases, four non-infectious controls). Samples underwent histopathological evaluation (Hematoxylin and Eosin Staining and Wright-Giemsa staining), DIA proteomics analysis, and protein validation through immunohistochemistry and enzyme-linked immunosorbent assay (ELISA). Comparative analysis between Control (Con) and Infected (Inf) groups showed similar demographics but significantly elevated inflammatory markers in Inf. Histopathology revealed extensive bone destruction, marked inflammatory infiltration, fibrinoid necrosis, and altered hematopoietic cell populations in Inf specimens compared to Con. DIA proteomics identified 5930 quantifiable proteins, with 509 differentially expressed proteins (DEPs) between groups. Gene ontology and Kyoto encyclopedia of genes and genomes pathway analyses revealed significant enrichment of inflammation and immune response-related functions in Inf. COMMD1 was significantly downregulated while IL-17 was upregulated in Inf, as validated by immunohistochemistry and ELISA. DIA proteomics identified downregulated COMMD1 and upregulated IL-17 in TM-induced bone destruction, suggesting potential diagnostic biomarkers and therapeutic targets through inflammatory pathway modulation.

Microsporidia are single-celled, fungi-related eukaryotic intracellular parasites able to infect a wide diversity of invertebrate and vertebrate hosts. Among them, Enterocytozoon bieneusi and Encephalitozoon spp. (including Enc. cuniculi, Enc. hellem, and Enc. intestinalis) are known causative agents of infectious diseases in immunocompromised individuals, including HIV/AIDS patients and organ transplant recipients. Additionally, asymptomatic microsporidial infections seem more frequent than initially anticipated and might represent an overlooked public health threat. Here, we provide novel data on the occurrence and genetic diversity of microsporidial infections in individual stool samples (n = 247) collected from apparently healthy schoolchildren (age range: 5-18 years; male/female ratio: 1.1) in Lusaka, Zambia. Stool DNA samples were analysed by PCR and Sanger sequencing methods. A basic epidemiological questionnaire was used to retrieve data on variables potentially linked with higher odds of harbouring E. bieneusi infections. A high prevalence rate was found for E. bieneusi (9.3%, 23/247; 95% CI: 6.0-13.6), whereas Enc. intestinalis was much less frequent (0.4%, 1/247; 95% CI: 0.01-2.2). Four known (D, S2, S6, and Type IV) and three novel (HhZbEb1, HhZbEb2, and HhZbEb3) genotypes were identified within E. bieneusi. Genotype D was the predominant genotype found (30.8%, 4/13), followed by genotypes Type IV, HhZbEb2, and HhZbEb3 (15.4%, 2/13 each), and genotypes S2, S6, and HhZbEb1 (7.7%, 1/13 each). The only Encephalitozoon-positive sample was identified as Enc. intestinalis. Subclinical infections by E. bieneusi were common in the investigated paediatric population. Infected children could act as disregarded spreaders of microsporidial pathogens at the community level, thus representing a potential public health concern.

Pentraxin 3 (Ptx3) is an acute-phase protein that specifically targets fungal galactosaminogalactan and has been proposed as a promising biomarker for invasive fungal infections. However, its stability in clinical samples over time has not yet been established. This study aimed to evaluate the stability of Ptx3 in serum and bronchoalveolar lavage fluid (BALF) samples during mid- and long-term storage. A total of 44 serum and 52 BALF samples were examined or re-examined for Ptx3 concentrations using enzyme immunoassay in pooled and individual sample formats. Samples were stored at -80°C, -20°C, and +37°C for periods ranging from 0 to 56 months. Statistical analyses included a paired two-sample Wilcoxon signed-rank test, analysis of variance, Bonferroni test, and linear regression analysis. Ptx3 remained highly stable in serum and BALF samples for up to 8 months at -20°C, with variations ranging from -1.8% to +2.8%. Long-term stability was observed at -80°C for 48 months, followed by a slow decline in Ptx3 levels. In contrast, storage at +37°C resulted in rapid degradation, with a 36.5%-60.7% increase or a 92.9%-97% decrease in Ptx3 levels in serum and BALF, respectively. These findings confirm that Ptx3 is a stable and reliable biomarker for invasive fungal infections when appropriate storage conditions are maintained.

(1→3)-ß-d-glucans (BDG), major cell wall components of most pathogenic fungi, are useful for the diagnosis of invasive fungal diseases (IFD) due to their high negative predictive value. For several years, a number of BDG detection tests are commercially available, including Fungitell Assay (FA) and Wako assay, and more recently Fungitell STAT (STAT) unit test. Our aim was to compare the performance of the two Fungitell assays for IFD diagnosis. Sera from 90 patients with Pneumocystis jirovecii pneumonia (PJP, n = 30), candidemia (n = 30), and invasive pulmonary aspergillosis (IPA, n = 30), 30 patients colonized by P. jirovecii, and 70 healthy controls (women followed-up during pregnancy) were analyzed retrospectively. STAT and FA assays were performed according to manufacturer's instructions. The overall level of agreement between two Fungitell assays was excellent (weighted Cohen's kappa = 0.87 [95% CI: 0.80-0.94]). BDG rates were significantly higher in candidemia, IPA and PJP than in healthy controls (P < .0001). BDG rates were also significantly higher in PJP than for P. jirovecii colonization (P < .0001). Area Under the Curve (AUC) of STAT (0.92) was higher than FA (0.86) for IFD diagnosis. Using optimized positivity thresholds for IFD diagnosis (94 pg/ml and 0.86 for FA and STAT, respectively), sensitivities and specificities were 78.9% and 90% for FA and 85.6% and 88.6% for STAT, respectively. AUC of FA and STAT were higher for PJP diagnosis than for candidemia and IPA diagnosis. Compared to FA, STAT assay represents an interesting option for emergency IFD diagnosis and for small care centers.

Fungal infections affect 2% of Malaysia's population, yet little is known about mycology laboratory practices in the country. This study surveyed 48 medical institutions, including 14 state hospitals, 26 major specialist hospitals, 4 minor specialist hospitals, 3 university hospitals, and 1 reference laboratory, to assess current practices and identify areas for improvement. Nearly all hospitals performed germ tube testing for Candida albicans (87.5%, 42/48). Yeast identification was conducted using API® (52%, 25/48) or VITEK® (52%, 25/48), with two institutions employing both methods. Advanced methods like matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) were used in only 39.6% (19/48) of institutions, while PCR and DNA sequencing (6.3%, 3/48 each) were limited to university and reference labs. Mould identification primarily relied on the tease mount method (91.7%, 44/48), indicating widespread capability for morphological identification. Antifungal susceptibility testing for yeast was available in all hospitals except minor specialist hospitals, using VITEK® (35.4%, 17/48), Sensititre® (20.8%, 10/48), or Etest® (8.3%, 4/48). Serology testing focused on opportunistic mycoses, particularly Cryptococcus spp. (50.0%, 24/48), while testing for endemic pathogens like Histoplasma was rare (2.1%, 1/48). Aspergillosis testing was limited to galactomannan enzyme immunoassay and lateral flow assay (6.3%, 3/48 each), and no institutions performed (1,3)-beta-d-glucan testing. While advanced diagnostics were available in state and major hospitals, minor specialist hospitals lacked access. These findings highlight the urgent need to enhance laboratory infrastructure, expand access to advanced diagnostics like MALDI-TOF, and train personnel to improve fungal infection management in Malaysia.

The Candida parapsilosis complex, consisting of C. parapsilosis sensu stricto, C. orthopsilosis, and C. metapsilosis, is a major cause of Candida onychomycosis. Increasing reports of high levels of resistance to antifungal drugs, particularly fluconazole and echinocandin, have raised concerns about C. parapsilosis complex. This study investigates antifungal resistance and hydrolytic enzyme activity in these species. Species were identified using polymerase chain reaction (PCR)-restriction fragment length polymorphism (RFLP) and internal transcribed spacer (ITS) 1-4 sequencing. Antifungal susceptibility was assessed using Sensititre™ YeastOne™. Hydrolytic enzyme production was assessed by agar plate culture. Among 43 isolates, C. parapsilosis sensu stricto was most prevalent (48.8%, n = 21/43), followed by C. orthopsilosis (39.6%, n = 17/43) and C. metapsilosis (11.6%, n = 5/43). All C. parapsilosis sensu stricto isolates were susceptible to antifungal agents, except 4.8% (n = 1/21) showing dose-dependent susceptibility to fluconazole and 4.8% (n = 1/21) resistance to amphotericin B. Candida orthopsilosis showed significant resistance to fluconazole and voriconazole (52.9% each, n = 9/17), posaconazole (23.5%, n = 4/17), and low resistance to amphotericin B (5.9%, n = 1/17). One C. metapsilosis isolate (20%) showed cross-resistance to fluconazole and voriconazole, and another (20%) was resistant to 5-flucytosine. Enzymatic assays showed higher protease and lipase activity in C. parapsilosis sensu stricto and C. orthopsilosis compared to C. metapsilosis, with C. parapsilosis sensu stricto showing the highest protease activity. Comprehensive research into antifungal susceptibility and virulence factors of the C. parapsilosis species complex is essential to monitor the growing threat of antifungal resistance and to better understand its role in onychomycosis pathogenesis.