Non-Aspergillus Hyaline Molds: A Host-Based Perspective of Emerging Pathogenic Fungi Causing Sinopulmonary Diseases

Invasive fungal disease in the immunocompromised host: changing epidemiology, new antifungal therapies, and management challenges

BACKGROUND

Invasive fungal disease (IFD) causes morbidity and mortality in immunocompromised hosts (ICHs). Based on increasing recognition of the impact of IFD on human disease, a recent WHO priority list identified key areas of need.

OBJECTIVES

This review examines changes in the epidemiology of IFD, in particular the emergence of antifungal-resistant pathogens and the current availability of rapid diagnostic tests and antifungal treatment options.

SOURCES

Literature between 2000 and January 2024 regarding fungal epidemiology, diagnostic tests, antifungal resistance, emerging fungal pathogens, and novel antifungal agents in both adult and paediatric ICH were reviewed.

CONTENT

We describe the changing epidemiology and continued burden and mortality of IFD in ICH. Furthermore, we discuss the emergence of antifungal-resistant organisms driven by new immunosuppressed populations, climate change, and antifungal exposure in the individual and environment. We highlight novel antifungal agents and how they will address current unmet needs.

IMPLICATIONS

The changing epidemiology and increased population at risk for IFD, lack of recognition or quantification of risks for IFD with new therapies, current gaps in the availability of rapid diagnostic tests, and the imminent availability of novel antifungals with distinct spectra of activity argue for improved availability of and access to rapid diagnostics, antifungal stewardship programmes, and global access to antifungal agents.

Antifungal properties of cathelicidin LL-37: current knowledge and future research directions

The threat of fungal diseases is substantially underestimated worldwide, but they have serious consequences for humans, animals, and plants. Given the limited number of existing antifungal drugs together with the emergence of drug-resistant strains, many researchers have actively sought alternatives or adjuvants to antimycotics. The best way to tackle these issues is to unearth potential antifungal agents with new modes of action. Antimicrobial peptides are being hailed as a promising source of novel antimicrobials since they exhibit rapid and broad-spectrum microbicidal activities with a reduced likelihood of developing drug resistance. Recent years have witnessed an explosion in knowledge on microbicidal activity of LL-37, the sole human cathelicidin. Herein, we provide a summary of the current understanding about antifungal properties of LL-37, with particular emphasis on its molecular mechanisms. We further illustrate fruitful areas for future research. LL-37 is able to inhibit the growth of clinically and agronomically relevant fungi including Aspergillus, Candida, Colletotrichum, Fusarium, Malassezia, Pythium, and Trichophyton. Destruction of the cell wall integrity, membrane permeabilization, induction of oxidative stress, disruption of endoplasmic reticulum homeostasis, formation of autophagy-like structures, alterations in expression of numerous fungal genes, and inhibition of cell cycle progression are the key mechanisms underlying antifungal effects of LL-37. Burgeoning evidence also suggests that LL-37 may act as a potential anti-virulence peptide. It is hoped that this review will not only motivate researchers to conduct more detailed studies in this field, but also inspire further innovations in the design of LL-37-based drugs for the treatment of fungal infections.

Scedosporium Sinusitis: A Rare Opportunistic Infection

Scedosporium sinusitis is an opportunistic fungal infection that is difficult to treat due to its inherent resistance to many antifungal agents. Infections may cause both localized or disseminated disease usually in skin and soft tissues. Immunocompetent persons are typically unaffected and disseminated disease occurs in immunocompromised hosts. Scedosporiumis a common hyaline mold causing sinopulmonary disease in those with hematologic malignancies and neutropenia. A 38-year-old Caucasian male with a medical history significant for HIV with intermittent treatment compliance, high-grade diffuse large B cell lymphoma (DLBCL) on chemotherapy, and hemophagocytic lymphohistiocytosis (HLH) presented with right-sided facial pain and fever. Maxillofacial computed tomography (CT) showed thickening and opacification of the sphenoid and maxillary sinuses concerning for fungal sinusitis. Endoscopic transsphenoidal debridement showed fungal growth of Scedosporium and the patient's blood cultures were ultimately negative. The patient underwent debridement of fungal sinusitis as well as right medial maxillectomy and ethmoidectomy. A three-month course of voriconazole was started and completed with weekly liver enzyme tests to monitor medication side effects. He has since been observed well as an outpatient with his oncologist after three months loss to follow-up and his infection has resolved.

Special Issue "Diagnosis and Treatment of Invasive Pulmonary Fungal Infections"

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