Medical mycology最新文献

Antifungal stewardship is important for promoting quality care and tackling the emergence of drug resistance. Evaluation of the quantity and appropriateness of common antifungal prescriptions like fluconazole is essential in the development of these programmes. To perform a clinical audit of fluconazole prescribing and explore whether involvement of pharmacy students in this process was feasible and meaningful from both pharmacy student and health system perspectives. An audit was conducted of all fluconazole prescriptions from January 2024 to March 2024 at two Sydney hospitals. Trained pharmacy students, under the supervision of antimicrobial stewardship pharmacists and physicians, completed the audit using the Antifungal National Antimicrobial Prescribing Survey audit tool. Prescriptions were assessed for their compliance to guidelines and appropriateness. Data on pharmacy students' educational experience was collected by a 5-point Likert scale survey. A total of 145 fluconazole prescriptions were audited: 34 for empiric therapy, 56 for directed therapy, and 56 for prophylaxis. A total of 91 (62.8%) prescriptions were assessed as appropriate, 46 (31.7%) were inappropriate, and 8 (5.5%) were not assessable. Potential drug-drug interactions were identified in 17 patients receiving fluconazole doses of 200 mg or greater, of which three were clinically significant, requiring intervention. Students had positive experiences contributing to quality use of medicines, in terms of enjoyment, support, and education. Inappropriate fluconazole use was common. Pharmacy students made a positive contribution to the antifungal audit, promoting good stewardship practises for the hospital while accessing enhanced learning and development opportunities.

Sporothrix schenckii is the most prevalent etiological agent of sporotrichosis in Mexico, a neglected subcutaneous mycosis with hyperendemic foci in mountainous regions. Despite its public health importance, the phenotypic and virulence-related features of clinical isolates circulating in these areas remain poorly characterized. Ten clinical isolates were molecularly identified and assessed for virulence by determining enzymatic activity (proteases, lipases, catalase), biofilm formation, adhesion to extracellular matrix proteins, antifungal susceptibility, and cell wall composition. Host interaction was evaluated through cytokine profiling in human peripheral blood mononuclear cells, and virulence was assessed using the Galleria mellonella invertebrate infection model. All isolates were confirmed as S. schenckii. Compared to a reference strain, a subset of isolates (740, 742, 183, and 1798) displayed reduced adhesion, extracellular enzymatic activity, and catalase production, as well as altered mannose and rhamnose cell wall content. These isolates induced significantly lower TNFα and higher IL-10 levels in PBMCs and were markedly less virulent in G. mellonella, exhibiting lower mortality, cytotoxicity, and immune activation. All isolates were biofilm producers, and some showed reduced susceptibility to itraconazole or fluconazole. This study reveals phenotypic diversity among S. schenckii clinical isolates in a Mexican hyperendemic region and identifies a subgroup with reduced virulence and immune stimulation capacity. These findings enhance our understanding of the host-pathogen dynamics of sporotrichosis and may inform future diagnostic and therapeutic strategies in endemic settings.

The human skin is a crucial defense system, protecting against external stressors. However, the skin also hosts various microorganisms that impact skin health and disease. Therefore, the polymicrobial interaction in the skin is particularly interesting since it can significantly influence alterations in the virulence traits of microbes and the immune responses of the hosts. This study aimed to investigate the influence of Malassezia restricta, a predominant fungal species on human skin, on the virulence of Staphylococcus aureus, a prominent skin bacterium associated with atopic dermatitis. Our findings revealed that M. restricta effectively interferes with the invasion of S. aureus into human keratinocytes, suggesting a potential mechanism for influencing bacterial infection by the fungus. Additionally, we observed that M. restricta exhibits fibronectin binding capabilities, a key mediator in the S. aureus invasion of keratinocytes. Physicochemical analysis indicated the involvement of a heat-unstable component, likely a M. restricta cell surface protein, which necessitates physical contact between the fungus and keratinocytes for fibronectin binding. Collectively, our results suggest the influential role of M. restricta in the pathogenesis of S. aureus and reveal a novel aspect of this fungal species within the human skin microbial community.

Early diagnosis and treatment are essential for improving outcomes of coccidioidal meningitis. While the detection of IgG by serologic testing of the cerebrospinal fluid (CSF) has been a mainstay of diagnosis for years, the diagnosis of coccidioidal meningitis in clinical practice can be very challenging due to suboptimal sensitivity of laboratory tests. We reviewed the results of the CSF diagnostic test results from the initial lumbar puncture in 110 patients with proven, probable, and likely coccidioidal meningitis from 1989 to 2024. One hundred four patients were diagnosed with coccidioidal meningitis on the initial CSF examination. The positivity rate of the first CSF testing was 89.1% (n = 64) for IgG by enzyme immunoassay, 62.2% (n = 98) for IgG by immunodiffusion, and 70.2% (n = 104) for IgG by complement fixation, 4.4% (n = 90) for fungal culture, 18.8% (n = 69) for polymerase chain reaction, and 33% (n = 21) for Coccidioides antigen. The non-specific fungal marker 1,3-β-d-glucan was positive in the CSF in 70.4% (n = 27) of samples. Contrasted brain magnetic resonance imaging identified leptomeningeal enhancement in 53.1%. Optimal detection of coccidioidal meningitis requires a combination of diagnostic modalities.

Scedosporium/Lomentospora species are ubiquitous moulds that can cause deep-seated infections and allergic bronchopulmonary mycoses (ABPM). Serodiagnosis is currently performed by immunoprecipitation (IP) techniques, which are time-consuming and lack reproducibility. In addition, as antigenic extracts for these fungi are not commercially available, many centers stopped performing this analysis. Therefore, there is a need for automated quantitative alternatives, such as Enzyme linked Immunosorbent Assay (ELISA) . The aim of this study was to develop an ELISA for serodiagnosis of Scedosporium/Lomentospora infections. All sera received for Scedosporium/Lomentospora serodiagnosis expertise from April 2022 to February 2024 were tested in parallel using IP and an in-house ELISA with antigenic extracts from both Scedosporium apiospermum and Lomentospora prolificans. Clinical and biological data such as positive culture, total IgE level, and final diagnosis retained were also collected prospectively. The concordance between techniques was calculated, with χ² tests performed to investigate the correlation between ELISA and culture results or final diagnosis. We tested 58 serum samples from 41 different patients. The concordance between IP and ELISA was 64% for S. apiospermum and 62% for L. prolificans. ELISA results obtained with S. apiospermum antigen extract were significantly correlated with culture results (P < .001, χ² test). ELISA was also more effective than IP to diagnose ABPM. The Scedosporium/Lomentospora ELISA gave satisfactory results, particularly for S. apiospermum. Further validation on a larger cohort is required to implement this ELISA for routine practice instead of IP. In addition, studies should be conducted on purified native proteins or in combination with recombinant antigens to improve standardization.

Trichophyton indotineae has emerged as a significant global public health concern due to its role in recalcitrant dermatophytosis and antifungal treatment failure. Precise identification of T. indotineae is essential for timely and effective therapy, and for curbing the spread of antifungal resistance. However, current routine diagnostic methods are limited to reliably distinguish T. indotineae from other closely related dermatophytes. This study aimed to develop and evaluate three simple, cost-effective molecular methods for the accurate differentiation of T. indotineae. In silico analyses were performed to identify specific restriction enzyme cut sites within the internal transcribed spacer (ITS) region and the topoisomerase II gene of T. indotineae. A total of 430 dermatophyte isolates, including 267 previously identified by ITS sequencing and 163 clinical isolates of unknown identity, were subjected to PCR amplification of ITS and topoisomerase II followed by restriction fragment length polymorphism (PCR-RFLP) analysis using EarI (Eam11041) and BsuRI (HaeIII), respectively. Additionally, a previously described T. indotineae-specific PCR assay was evaluated. The enzyme EarI digested the ITS region of T. indotineae, producing a distinct PCR-RFLP pattern; likewise, BsuRI digested the topoisomerase II gene, enabling accurate differentiation of T. indotineae. The isolates previously identified by ITS sequencing were correctly classified by both methods, achieving high sensitivity and specificity. The T. indotineae-specific PCR assay demonstrated high sensitivity, although faint cross-reactivity was observed with T. tonsurans isolates. The ITS-PCR-RFLP and topoisomerase II-PCR-RFLP methods demonstrated high accuracy, affordability, and speed for the reliable identification of T. indotineae, making them suitable for routine use in clinical laboratories, especially in resource-limited settings. Although the T. indotineae-specific PCR assay showed high sensitivity, occasional cross-reactivity with T. tonsurans suggests that it should be interpreted with caution and ideally used alongside confirmatory tests.

We aim to describe the epidemiology and risk factors for invasive fungal infections (IFI) and invasive mould infections (IMI) in hospitalized hematologic patients within the context of current hematologic therapies. Retrospective observational cohort study conducted on consecutive hematologic patients admitted to a tertiary hospital (2020-2023). Two populations were analysed: the full cohort of hospitalized patients (FC) and the subset of patients for whom mycological testing was specifically requested to rule out an IFI (SC). Proven or probable IFI was classified using European Organization for Research and Treatment of Cancer criteria. Risk factors for IFI and IMI were identified. A total of 1975 patients were included in the FC, whereas 1154 were included in the SC. IFI was diagnosed in 64 patients (65 episodes), and IMI in 43 patients (44 episodes). Aspergillosis was the most common IFI (58.4%), followed by candidemia (18.5%), Pneumocystis jirovecii pneumonia (PJP) (15.4%), mucormycosis (6.2%), and fusariosis (4.6%). Independent risk factors for IFI in the FC included acute leukemia (aOR 2.40, 95% CI 1.37-4.10, P = .002), corticosteroid use (aOR 2.36, 95% CI 1.40-4.03, P = .001) and graft versus host disease (GVHD) (aOR 2.13, 95% CI 0.93-4.46, P = .05). For IMI, risk factors were acute leukemia (aOR 2.71, 95% CI 1.33-5.52, P = .006), corticosteroid use (aOR 1.96, 95% CI 0.98-4.03, P = .05) and chronic lung disease (aOR 2.25, 95% CI 1.06-4.5, P = .02). In the SC, corticosteroid use (aOR 2.45, 95% CI 1.44-4.25, P = .001) was the independent risk factor for IFI, and corticosteroid use (aOR 2.40, 95% CI 1.21-4.91, P = .01) and GVHD (aOR 2.95, 95% CI 1.23-6.52, P = .009) were independent factors associated with IMI. Mortality was significantly higher in IFI patients compared to non-IFI patients (51.6% vs. 20.3%, P < .001). In this new era of haematology, the epidemiology of IFI is shifting, with Pneumocystis, Mucorales, and Fusarium becoming more prevalent. While corticosteroids and GVHD remain key risk factors, factors such as chronic lung disease are increasing its importance. Prolonged neutropenia may have decreased in relevance, likely due to prophylaxis. Preventing PJP has become a new challenge in IFI management.

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.