Global warming impact on the expansion of fundamental niche of Cryptococcus gattii VGI in Europe

Cryptococcosis Associated With Biologic Therapy: A Narrative Review

Cryptococcus is an opportunistic fungal pathogen that can cause disseminated infection with predominant central nervous system involvement in patients with compromised immunity. Biologics are increasingly used in the treatment of neoplasms and autoimmune/inflammatory conditions and the prevention of transplant rejection, which may affect human defense mechanisms against cryptococcosis. In this review, we comprehensively investigate the association between cryptococcosis and various biologics, highlighting their risks of infection, clinical manifestations, and clinical outcomes. Clinicians should remain vigilant for the risk of cryptococcosis in patients receiving biologics that affect the Th1/macrophage activation pathways, such as tumor necrosis factor α antagonists, Bruton tyrosine kinase inhibitors, fingolimod, JAK/STAT inhibitors (Janus kinase/signal transducer and activator of transcription), and monoclonal antibody against CD52. Other risk factors-such as age, underlying condition, and concurrent immunosuppressants, especially corticosteroids-should also be taken into account during risk stratification.

Molecular characterization of clinical and environmental isolates from the Cryptococcus neoformans/C. Gattii species complexes of Maceió, Alagoas, Brazil

Cryptococcosis is one of the major life-threatening opportunistic/systemic fungal diseases of worldwide occurrence, which can be asymptomatic or establish pneumonia and meningoencephalitis mainly in immunosuppressed patients, caused by the Cryptococcus neoformans and C. gattii species complexes. Acquisition is by inhaling fungal propagules from avian droppings, tree hollows and decaying wood, and the association of the molecular types with geographic origin, virulence and antifungal resistance have epidemiological importance. Since data on cryptococcosis in Alagoas are limited, we sought to determine the molecular types of etiological agents collected from clinical and environmental sources. We evaluated 21 isolates previously collected from cerebrospinal fluid and from environment sources (pigeon droppings and tree hollows) in Maceió-Alagoas (Brazil). Restriction fragment length polymorphism of URA5 gene was performed to characterize among the eight standard molecular types (VNI-VNIV and VGI-VGIV). Among isolates, 66.67% (14) were assigned to C. neoformans VNI - 12 of them (12/14) recovered from liquor and 2 from a tree hollow (2/14). One isolate from pigeon droppings (4.76%) corresponded to C. neoformans VNIV, while five strains from tree hollows and one from pigeon droppings (6, 28.57%) to C. gattii VGII. VNI-type was present in clinical and environmental samples and most C. neoformans infections were observed in HIV-positive patients, while types VNIV and VGII were prevalent in environmental sources in Alagoas. This is the first molecular characterization of Cryptococcus spp. in Alagoas, our study provides additional information on the ecoepidemiology of Cryptococcus spp. in Brazil, contributing to a closer view of the endemic species.

Invasive Fungal Infections and Oomycoses in Cats: 1. Diagnostic approach

CLINICAL RELEVANCE

In contrast to superficial fungal infections, such as dermatophytosis, invasive fungal infections (IFIs) are characterised by penetration of tissues by fungal elements. Disease can spread locally within a region or can disseminate haematogenously or via the lymphatics. The environment is the most common reservoir of infection. Since fungal spores are airborne, indoor cats are also susceptible to IFIs. Some environmental fungi are ubiquitous and present globally, while others are endemic or hyperendemic within specific geographic regions. Zoonotic pathogens include Microsporum canis, Sporothrix schenckii and Sporothrix brasiliensis.

AIM

In the first of a two-part article series, the approach to the investigation of feline IFIs and oomycoses is reviewed. As well as tips for diagnosis, and information on the ecological niche and distribution of fungal pathogens, the review covers clinical presentation of the most common IFIs, including cryptococcosis, histoplasmosis, blastomycosis, coccidioidomycosis, sporotrichosis, phaeohyphomycosis, aspergillosis and dermatophytic pseudomycetoma, as well as the oomycoses pythiosis, lagenidiosis and paralagenidiosis. In Part 2, the spectrum of activity, mechanisms of action, pharmacokinetic and pharmacodynamic properties and adverse effects of antifungal drugs are reviewed, and the treatment and prognosis for specific IFIs and oomycoses are discussed.

EVIDENCE BASE

The review draws on published evidence and the authors' combined expertise in feline medicine, mycology, dermatology, clinical pathology and anatomical pathology.

A New Paradigm for Pandemic Preparedness

Purpose of Review

Preparing for pandemics requires a degree of interdisciplinary work that is challenging under the current paradigm. This review summarizes the challenges faced by the field of pandemic science and proposes how to address them.

Recent Findings

The structure of current siloed systems of research organizations hinders effective interdisciplinary pandemic research. Moreover, effective pandemic preparedness requires stakeholders in public policy and health to interact and integrate new findings rapidly, relying on a robust, responsive, and productive research domain. Neither of these requirements are well supported under the current system.

Summary

We propose a new paradigm for pandemic preparedness wherein interdisciplinary research and close collaboration with public policy and health practitioners can improve our ability to prevent, detect, and treat pandemics through tighter integration among domains, rapid and accurate integration, and translation of science to public policy, outreach and education, and improved venues and incentives for sustainable and robust interdisciplinary work.

The role of methionine synthases in fungal metabolism and virulence

Methionine synthases (MetH) catalyse the methylation of homocysteine (Hcy) with 5-methyl-tetrahydrofolate (5, methyl-THF) acting as methyl donor, to form methionine (Met) and tetrahydrofolate (THF). This function is performed by two unrelated classes of enzymes that differ significantly in both their structures and mechanisms of action. The genomes of plants and many fungi exclusively encode cobalamin-independent enzymes (EC.2.1.1.14), while some fungi also possess proteins from the cobalamin-dependent (EC.2.1.1.13) family utilised by humans. Methionine synthase's function connects the methionine and folate cycles, making it a crucial node in primary metabolism, with impacts on important cellular processes such as anabolism, growth and synthesis of proteins, polyamines, nucleotides and lipids. As a result, MetHs are vital for the viability or virulence of numerous prominent human and plant pathogenic fungi and have been proposed as promising broad-spectrum antifungal drug targets. This review provides a summary of the relevance of methionine synthases to fungal metabolism, their potential as antifungal drug targets and insights into the structures of both classes of MetH.

Fertile Cryptococcus neoformans var. neoformans (C. deneoformans) isolates from natural environment in Kosovo

A total of 300 tree-associated samples were collected from green areas in three towns in Kosovo, and cultured to isolate Cryptococcus species. One soil sample from Prizren tested positive, yielding three isolates identified as C. neoformans var. neoformans (C. deneoformans), molecular type VNIV, two MATα, and one MATa. Mating experiments revealed that they were fertile when crossed together, and multilocus sequence typing analysis showed unique sequence types not found in the global database. The study reports the presence of C. neoformans strains in the environment in Kosovo and highlights the importance of monitoring pathogen distribution and the potential impacts of climate change.

Environmental and bioclimatic factors influencing yeasts and molds distribution along European shores

The present study employed data collected during the Mycosands survey to investigate the environmental factors influencing yeasts and molds distribution along European shores applying a species distribution modelling approach. Occurrence data were compared to climatic datasets (temperature, precipitation, and solar radiation), soil datasets (chemical and physical properties), and water datasets (temperature, salinity, and chlorophyll-a concentration) downloaded from web databases. Analyses were performed by MaxEnt software. Results suggested a different probability of distribution of yeasts and molds along European shores. Yeasts seem to tolerate low temperatures better during winter than molds and this reflects a higher suitability for the Northern European coasts. This difference is more evident considering suitability in waters. Both distributions of molds and yeasts are influenced by basic soil pH, probably because acidic soils are more favorable to bacterial growth. Soils with high nitrogen concentrations are not suitable for fungal growth, which, in contrast, are optimal for plant growth, favored by this environment. Finally, molds show affinity with soil rich in nickel and yeasts with soils rich in cadmium resulting in a distribution mainly at the mouths of European rivers or lagoons, where these metals accumulate in river sediments.

What's New in Cryptococcus gattii: From Bench to Bedside and Beyond

Cryptococcus species are a major cause of life-threatening infections in immunocompromised and immunocompetent hosts. While most disease is caused by Cryptococcus neoformans, Cryptococcus gattii, a genotypically and phenotypically distinct species, is responsible for 11-33% of global cases of cryptococcosis. Despite best treatment, C. gattii infections are associated with early mortality rates of 10-25%. The World Health Organization's recently released Fungal Priority Pathogen List classified C. gattii as a medium-priority pathogen due to the lack of effective therapies and robust clinical and epidemiological data. This narrative review summarizes the latest research on the taxonomy, epidemiology, pathogenesis, laboratory testing, and management of C. gattii infections.

Climate change, human health, and the exposome: Utilizing OMIC technologies to navigate an era of uncertainty

Climate change is an anthropogenic phenomenon that is alarming scientists and non-scientists alike. The emission of greenhouse gases is causing the temperature of the earth to rise and this increase is accompanied by a multitude of climate change-induced environmental exposures with potential health impacts. Tracking human exposure has been a major research interest of scientists worldwide. This has led to the development of exposome studies that examine internal and external individual exposures over their lifetime and correlate them to health. The monitoring of health has also benefited from significant technological advances in the field of "omics" technologies that analyze physiological changes on the nucleic acid, protein, and metabolism levels, among others. In this review, we discuss various climate change-induced environmental exposures and their potential health implications. We also highlight the potential integration of the technological advancements in the fields of exposome tracking, climate monitoring, and omics technologies shedding light on important questions that need to be answered.

Three Models of Vaccination Strategies Against Cryptococcosis in Immunocompromised Hosts Using Heat-Killed Cryptococcus neoformans Δsgl1

Vaccines are one of the greatest medical accomplishments to date, yet no fungal vaccines are currently available in humans mainly because opportunistic mycoses generally occur during immunodeficiencies necessary for vaccine protection. In previous studies, a live, attenuated Cryptococcus neoformans Δsgl1 mutant accumulating sterylglucosides was found to be avirulent and protected mice from a subsequent lethal infection even in absence of CD4⁺ T cells, a condition most associated with cryptococcosis (e.g., HIV). Here, we tested three strategies of vaccination against cryptococcosis. First, in our preventative model, protection was achieved even after a 3-fold increase of the vaccination window. Second, because live C. neoformans Δsgl1-vaccinated mice challenged more than once with WT strain had a significant decrease in lung fungal burden, we tested C. neoformans Δsgl1 as an immunotherapeutic. We found that therapeutic administrations of HK C. neoformans Δsgl1 post WT challenge significantly improves the lung fungal burden. Similarly, therapeutic administration of HK C. neoformans Δsgl1 post WT challenge resulted in 100% or 70% survival depending on the time of vaccine administration, suggesting that HK Δsgl1 is a robust immunotherapeutic option. Third, we investigated a novel model of vaccination in preventing reactivation from lung granuloma using C. neoformans Δgcs1. Remarkably, we show that administration of HK Δsgl1 prevents mice from reactivating Δgcs1 upon inducing immunosuppression with corticosteroids or by depleting CD4⁺ T cells. Our results suggest that HK Δsgl1 represents a clinically relevant, efficacious vaccine that confers robust host protection in three models of vaccination against cryptococcosis even during CD4-deficiency.

Vaccine protection by Cryptococcus neoformans Δsgl1 is mediated by γδ T cells via TLR2 signaling

We previously reported that administration of Cryptococcus neoformans Δsgl1 mutant vaccine, accumulating sterylglucosides (SGs) and having normal capsule (GXM), protects mice from a subsequent infection even during CD4⁺ T cells deficiency, a condition commonly associated with cryptococcosis. Here, we studied the immune mechanism that confers host protection during CD4⁺T deficiency. Mice receiving Δsgl1 vaccine produce IFNγ and IL-17A during CD4⁺ T (or CD8⁺ T) deficiency, and protection was lost when either cytokine was neutralized. IFNγ and/or IL-17A are produced by γδ T cells, and mice lacking these cells are no longer protected. Interestingly, ex vivo γδ T cells are highly stimulated in producing IFNγ and/or IL-17A by Δsgl1 vaccine, but this production was significantly decreased when cells were incubated with C. neoformans Δcap59/Δsgl1 mutant, accumulating SGs but lacking GXM. GXM modulates toll-like receptors (TLRs), including TLR2. Importantly, neither Δsgl1 nor Δcap59/Δsgl1 stimulate IFNγ or IL-17A production by ex vivo γδ T cells from TLR2^-/- mice. Finally, TLR2^-/- animals do not produce IL-17A in response to Δsgl1 vaccine and were no longer protected from WT challenge. Our results suggest that SGs may act as adjuvants for GXM to stimulate γδ T cells in producing IFNγ and IL-17A via TLR2, a mechanism that is still preserved upon CD4⁺ T deficiency.

Prevalence, Genetic Structure, and Antifungal Susceptibility of the Cryptococcus neoformans/C. gattii Species Complex Strains Collected from the Arboreal Niche in Poland

Fungi belonging to the Cryptococcus neoformans/C. gattii species complex (CNGSC) are etiological agents of serious and not infrequently fatal infections in both humans and animals. Trees are the main ecological niche and source of potential exposition concerning these pathogens. With regard to epidemiology of cryptococcosis, various surveys were performed worldwide, enabling the establishment of a map of distribution and genetic structure of the arboreal population of the CNGSC. However, there are regions, among them Central and Eastern Europe, in which the data are lacking. The present study shows the results of such an environmental study performed in Wrocław, Poland. The CNGSC strains were detected in 2.2% of the tested trees belonging to four genera. The obtained pathogen population consisted exclusively of C. neoformans, represented by both the major molecular type VNI and VNIV. Within the tested group of isolates, resistance to commonly used antimycotics was not found, except for 5-fluorocytosine, in which about 5% of the strains were classified as a non-wild type.