Diagnostic Mycology Laboratories Should Have a Central Role for the Management of Fungal Disease

In vitro activity of manogepix and comparators against infrequently encountered yeast and mold isolates from the SENTRY Surveillance Program (2017-2022)

Manogepix is a potent new antifungal agent targeting the fungal Gwt1 enzyme. Manogepix has previously demonstrated potent in vitro activity against clinical isolates of both Candida (except Candida krusei) and Aspergillus species. This study determined the in vitro activity of manogepix and comparators against a large collection of infrequently encountered yeast and molds. Manogepix demonstrated potent in vitro activity against infrequently encountered yeasts exhibiting elevated MIC values to other drug classes, including Candida spp. (MIC50/90, 0.008/0.12 mg/L), Saprochaete clavata (Magnusiomyces clavatus) (MIC50/90, 0.03/0.06 mg/L), Magnusiomyces capitatus (MICrange, 0.016-0.06 mg/L), Rhodotorula minuta (MIC, 0.016 mg/L), and Rhodotorula mucilaginosa (MIC50/90, 0.03/0.12 mg/L). Similarly, manogepix was active against infrequently encountered mold isolates and strains exhibiting elevated MIC/MEC values to echinocandins, azoles, and amphotericin B, including Coprinopsis cinerea (MEC, 0.004 mg/L), Fusarium spp. (MEC50/90, 0.016/0.06 mg/L), Fusarium (Gibberella) fujikuroi species complex (MEC50/90, 0.016/0.03 mg/L), Lomentospora prolificans (MEC50/90, 0.03/0.06 mg/L), Microascus cirrosus (MEC, 0.008 mg/L), Paecilomyces spp. (MEC50/90, ≤0.008/0.016 mg/L), Pleurostomophora richardsiae (MEC, 0.06 mg/L), Sarocladium kiliense (MEC range, 0.016-0.12 mg/L), and Scedosporium spp. (MEC50/90, 0.03/0.06 mg/L). Manogepix demonstrated potent activity against a majority of the infrequently encountered yeast and mold isolates tested including strains with elevated MIC/MEC values to other drug classes. Additional clinical development of manogepix (fosmanogepix) in difficult-to-treat, resistant fungal infections is warranted.

The Nairobi Declaration 2023: A commitment to address deadly yet neglected fungal diseases in Africa

On May 30th and 31st, 2023, delegates representing various African subregions, together with global representatives from the International Society of Human and Animal Mycology (ISHAM), the European Confederation of Medical Mycology (ECMM), the United States Centre for Disease Control and Prevention (CDC), and Global Action for Fungal Infections (GAFFI), convened in Nairobi, Kenya under the aegis of the Pan African Mycology Working Group, a working group of ISHAM. The meeting objectives were, amongst others, to deliberate on a continental response to the World Health Organisation Fungal Priority Pathogen List and facilitate interaction between global and regional leaders. Country delegates and international speakers addressed Africa's fungal disease burden; capacity for diagnosis and management; ongoing surveillance; knowledge gaps and trends in invasive fungal diseases such as Candida auris, mucormycosis, aspergillosis, and Acquired Immune Deficiency Syndrome (AIDS)-related mycoses; and current laboratory practice. During the technical sessions, expert panels deliberated on establishing and financing of national/regional surveillance networks for mycoses; establishing and sustaining African-led collaborations; expanding on existing laboratory and point-of-care diagnostic capacity as well as planning a mycology reference laboratory service and network in Africa. The meeting also highlighted successful African-led collaborations, capacity building, and clinical trial initiatives. The meeting conclusions informed the resolutions of the Nairobi Declaration calling for improved awareness; strong collaborations between clinical and laboratory teams across Africa; improved fungal disease surveillance within the continent; access to antifungals and diagnostics; and leveraging qualified human resources for mycology present within and outside Africa to facilitate trainings, collaborations, and exchanges.

Evaluation of the yeast phase-specific monoclonal antibody 4D1 and Galanthus nivalis agglutinin sandwich ELISA to detect Talaromyces marneffei antigen in human urine

Talaromyces (Penicillium) marneffei (TM) is an important, but neglected, thermally dimorphic fungus. It is the pathogenic cause of talaromycosis, which is strongly associated with the immunodeficiency state present in individuals with advanced HIV disease. The purpose of this study was to develop a sandwich enzyme-linked immunosorbent assay (sandwich ELISA) for the detection of T. marneffei cytoplasmic yeast antigen (TM CYA) in human urine. Monoclonal antibody (MAb) 4D1 specifically binds to TM CYA. Galanthus nivalis agglutinin (GNA), a mannose -binding lectin, recognizes and binds to mannose residues of TM CYA. For the sandwich ELISA, the microplate was coated with GNA as the capturing molecule for absorbing immune complexes of MAb 4D1-TM CYA. The MAb 4D1-GNA sandwich ELISA did not detect a cross-reaction with other antigens from other fungi or bacteria. Seventy-four urine samples from patients with blood culture -confirmed talaromycosis and 229 urine samples from people without talaromycosis residing in the endemic area were subjected to the MAb 4D1-GNA sandwich ELISA. At an optical density (OD) cutoff value of 0.356, the sensitivity was 89.19% [95% confidence interval (CI): 79.80% -95.22%]; the specificity was 98.69% (95% CI: 96.22% -99.73%). The diagnostic performance of the MAb 4D1-GNA sandwich ELISA was highly consistent with those of blood culture and the Platelia Aspergillus galactomannan (GM) ELISA kit. Collectively, the MAb 4D1-GNA sandwich ELISA is a promising technique for the rapid diagnosis of T. marneffei infection, which would facilitate the early treatment of patients with talaromycosis and it may be used to monitor treatment responses.

Dynamic full-field optical coherence tomography for live-cell imaging and growth-phase monitoring in Aspergillus fumigatus

Introduction

The diagnosis of cutaneous manifestations of deep mycoses relies on both histopathological and direct examinations. Yet, the current diagnostic criteria cannot prevent missed cases, including invasive aspergillosis, which requires the development of a novel diagnostic approach and imaging tools. We recently introduced the use of dynamic full-field optical coherence tomography (D-FF-OCT) in fungal diagnostics with a definition approaching that of conventional microscopy and the ability to return metabolic information regarding different fungal species. The present work focuses on subcellular dynamics and live-cell imaging of Aspergillus fumigatus with D-FF-OCT to follow the fungal growth stages.

Methods

The A. fumigatus ATCC 204305 quality-control strain was used for all imaging experiments, following incubation times varying between 24 and 72 h at 30°C in a humidified chamber on Sabouraud dextrose agar. Fungal growth was subsequently monitored with D-FF-OCT for up to 5 h at room temperature and following the pharmacological stress of either voriconazole, amphotericin B, or caspofungin gradient concentration.

Results

D-FF-OCT images allow not only the visualization of intracellular trafficking of vacuoles but also an evolving dynamic segmentation of conidiophores depending on the chronological development and aging of the hyphae or the effect of antifungal treatment. The same applies to conidial heads, with the most intense D-FF-OCT signal coming from vesicles, revealing a changing dynamic within a few hours only, as well as complete extinction following subsequent drying of the Sabouraud dextrose agar.

Discussion

These results provide additional data on the ability of D-FF-OCT to monitor some of the main life cycle processes, dynamics, and intracellular trafficking of vacuoles in A. fumigatus, with or without the effect of pharmacological stress. Such complementary metabolic information could help both clinicians and microbiologists in either mechanistic studies toward experimental mycology or the development of a potential D-FF-OCT-guided diagnosis of superficial fungal infections.