Mycopathologia最新文献

Introduction: Cryptococcosis is a systemic mycosis prevalent in immunosuppressed individuals, particularly those with HIV/AIDS. Immune recovery achieved through antiretroviral therapy (ART) is crucial for controlling opportunistic infections in AIDS. Given clinical observations and evidence suggesting Cryptococcus spp. accelerates HIV replication in vitro, we hypothesized that cryptococcosis may hinder immune recovery in severely immunosuppressed AIDS patients.

Objective: To investigate the association between cryptococcosis and immune recovery in AIDS patients with severe immunosuppression (CD4 + T-cells ≤ 200 cells/mm³) after starting ART.

Methods: From 230 consecutive patients, those followed for > 100 days were included in a matched cohort study: 21 with cryptococcosis and 67 without, matched by CD4 + T-cells range at a 3:1 ratio. Immune recovery was defined as achieving a CD4 + T-cells count ≥ 350 cells/mm³. Statistical analyses included chi-square, Fisher's exact, Mann-Whitney U tests, multivariate logistic regression, and Kaplan-Meier curves analyzed with Log Rank. A p-value < 0.05 was significant.

Results: Immune recovery rates were lower in the cryptococcosis group (19.0 vs. 38.8%, p = 0.096). Multivariate analysis revealed that younger age (< 40 years), undetectable HIV viral load, and longer follow-up were independently associated with immune recovery. Patients with cryptococcosis had a 3.61-fold increased odds of immune recovery failure (95% CI 0.90-14.53; p = 0.071), approaching statistical significance.

Conclusion: These findings suggest that cryptococcosis may impair immune recovery in AIDS patients with severe immunosuppression. Further studies with larger cohorts are needed to confirm these results.

Invasive candidiasis (IC) is a life-threatening fungal infection caused by Candida species. Current diagnostic methods are based on blood culture of the fungus, a technique with limited sensitivity and slow turnaround times. To address these limitations, novel diagnostic strategies are under investigation. This study evaluates the diagnostic potential of the Candida albicans germ tube protein Hyr1 and a subterminal Hyr1 fragment (D22b), both produced in an eukaryotic expression system, for the diagnosis of IC; for that purpose, recombinant Hyr1 and D22b were expressed in Pichia pastoris and tested by ELISA using sera from 176 patients at risk of invasive fungal infections. The diagnostic performance of these antigens was determined and compared with other biomarkers (CAGTA and β-D-glucan). Interestingly, the recombinant proteins exhibited higher apparent molecular weights than predicted, suggesting the presence of post-translational modifications. Serological detection of antibodies against the recombinant Hyr1 and D22b fragment successfully distinguished patients with IC caused by the most commonly isolated Candida species, achieving sensitivities greater than 70% and specificities above 80%. These findings highlight the potential of the serological detection of antibodies to Hyr1 and D22b as a promising diagnostic approach that overcomes the drawbacks of CAGTA detection and could serve as a valuable complement to blood culture, supporting earlier diagnosis and guiding timely treatment decisions in IC. Furthermore, comparing results obtained with antigens produced in eukaryotic and prokaryotic systems, results suggest that accurate protein folding and post-translational processing influence the success of the diagnostic technique.

Mycological diagnostics play a crucial role in patient management and treatment of invasive fungal infections. Despite the significant global burden of fungal diseases, awareness and diagnostic capabilities in mycology laboratories lag behind other microbiological disciplines. Mycological diagnostics often require microscopic analysis of clinical samples and culture. The interpretation of microscopy requires extensive expertise in clinical mycology. This study aimed to explore the feasibility of remote digital reading for preliminary identification of fungi. In this study, five mycology-trained participants were asked to analyze a total of 474 images divided into three main groups of yeasts (73 images), filamentous fungi (341 images), and direct fluorescent microscopy from clinical samples (60 images). The accuracy of the assessments varied, with an average correct decision rate between 78 and 93% across the three image groups. Individual participant's performance showed a mean accuracy rate ranging between 76 and 92%. A significant difference was observed in the assessment accuracy across specimen groups and among individual participants (p < 0.05). However, there was no significant interaction effect between participants and image group (p = 0.118). In conclusion, telemycology offers a promising alternative to standard microscopy diagnostics of fungal infections, especially in settings where skilled mycologists are lacking, including low- and middle-income countries.

Malassezia species are lipophilic yeasts that inhabit the skin of warm-blooded animals and that are associated with various skin disorders. Although Malassezia is frequently isolated from the external ear canal of cats, the influence of ectoparasites such as Otodectes cynotis (ear mites) on Malassezia species diversity has received limited attention. During an investigation of Malassezia diversity in cat ear canals infested with Otodectes cynotis, five Malassezia strains were isolated from the external ear canals. Phylogenetic analyses based on the internal transcribed spacer (ITS) region and the D1/D2 domains of the Large Subunit rDNA (LSU rDNA) revealed that those five isolates represent two known species, namely Malassezia globosa and Malassezia slooffiae, and a putative novel candidate species of Malassezia. The candidate species was found to be closely related to Malassezia gallinae and M. slooffiae, yet it differed from M. gallinae by 78 nucleotides (nt) in the ITS region and 9 nt in the D1/D2 domains, and from M. slooffiae by 70 nt in the ITS region and 5 nt in the D1/D2 domains. Based on phylogenetic analysis and phenotypic characteristics, we propose a novel species for which we suggest the name Malassezia cafarchiae sp. nov.

Aim: Invasive candidiasis is a major contributor to morbidity and mortality in hospitalized children, particularly in those with comorbidities or prolonged hospitalizations. This study evaluated the epidemiology, antifungal susceptibility, and outcomes of invasive Candida infections over an 11-year period.

Methods: A retrospective study was conducted at Hacettepe University Children's Hospital from 2013 to 2024. Pediatric patients with culture-confirmed invasive Candida infections were included. Data on species distribution, antifungal susceptibility, and clinical outcomes were analyzed.

Results: A total of 158 invasive candidiasis episodes were identified, yielding 166 Candida isolates. Candida albicans was most common (40.3%), followed by Candida parapsilosis SC (24.1%), Nakaseomyces glabratus (7.8%), Candida tropicalis (7.8%), Clavispora lusitaniae (7.2%), and others (12%). Candidemia accounted for 89.9% of cases; less common manifestations included meningitis, peritonitis, endocarditis, and pneumonia. Over time, C. albicans cases declined, while C. parapsilosis SC remained the predominant non-albicans species. Fluconazole resistance was highest in C. parapsilosis SC (13.2%). Overall mortality was 35.4%, with 14.6% directly attributed to invasive candidiasis. Catheter removal significantly reduced mortality (OR = 8.44, 95% CI: 2.81-25.3, p < 0.001).

Conclusions: Non-albicans Candida species became increasingly prevalent, while C. albicans declined. Mortality significantly decreased, likely due to improved patient management. Rising azole resistance in C. parapsilosis SC and the benefit of early catheter removal highlight the need for timely, species-specific strategies.

Sporotrichosis, caused by the thermodimorphic fungus Sporothrix brasiliensis, is an emerging zoonotic infection in Brazil and other Latin American countries. Typically, the parasitic form in host tissue is yeast; however, we report three cases in immunocompromised patients exhibiting simultaneous yeast and mycelial structures in biopsies. Identification of S. brasiliensis was confirmed through calmodulin gene sequencing, with phylogenetic analysis supporting species-level classification. Direct examination and histopathology revealed both budding yeast cells (3-8 μm) and hyphae, a rare morphological phenomenon previously unreported for this species in humans. This atypical dimorphism may be influenced by local tissue conditions, such as oxygen exposure and lower temperatures, and has significant diagnostic implications. Recognition of polymorphic forms is essential for pathologists and mycologists, highlighting the evolving histopathological and diagnostic challenges in sporotrichosis.

Background: Pneumocystis jirovecii pneumonia (PjP) is a life-threatening infection in immunocompromised individuals. Its diagnosis remains challenging, especially in microscopy-negative cases. This study aimed to standardize and validate a qPCR assay targeting the mtLSU rRNA gene for detecting P. jirovecii DNA in respiratory samples from patients in Argentina.

Materials and methods: The assay was optimized using plasmid dilutions containing the target gene. Analytical specificity was evaluated against 60 fungal, 21 mycobacterial, and 16 bacterial species. Clinical validation included 101 respiratory samples from symptomatic patients and 37 from healthy individuals. An internal positive control (IPC) was included in all reactions to detect inhibitors.

Results: The qPCR assay showed a detection limit of 8.8 copies/μL and no cross-reactivity. Among microscopy-confirmed cases, 95.5% were qPCR-positive. Notably, 14.9% of microscopy-negative but clinically compatible cases tested positive. ROC analysis yielded an AUC of 0.96, with an optimal Ct cutoff ≤ 36, providing 90.7% sensitivity and 95.8% specificity. No healthy controls tested positive. A "grey zone" (Ct 36-37.8) was observed, requiring clinical correlation.

Conclusions: This qPCR assay is highly sensitive and specific, offering a valuable diagnostic tool for PjP. Its performance supports implementation in routine diagnostics, especially when microscopy is inconclusive. However, interpretation in the grey zone requires complementary clinical or biomarker data.

The dermatophytes, classified in a single family Arthrodermataceae (Onygenales). This family has received more attention due to their keratin-degrading properties and the ability of some taxa to invade the skin and cause dermatophytes in humans and/or mammals. The phylogeny of Arthrodermataceae is remarkably stable, with Arthroderma representing the ancestral geophilic lineage and Trichophyton constituting a derived clade of anthropophiles and some zoophiles. The other genera appear to represent intermediate forms along this ecological spectrum. During a survey of Arthrodermataceae in China, a geophilic species was isolated. A multi-locus phylogenetic analysis of three markers (ITS, β-tubulin, and tef1-α) reveals that this taxon is a sister species to Arthroderma cuniculi. It can be differentiated from other species in Arthroderma by two types of microconidia: (i) smooth-walled, cylindrical to clavate, (ii) smooth-walled, obovate to pyriform. Phylogenetic analyses, and morphology provide evidence that the new isolate is a distinct species. This study enriches the Arthroderma species inventory and expands our understanding of dermatophyte biodiversity.