Cryptococcus gattii infections

Autochthonous Cryptococcus gattii genotype VGIIb infection in a Japanese patient with anti-granulocyte-macrophage colony-stimulating factor antibodies

A 31-year-old Japanese man presented with cerebral and pulmonary cryptococcosis. Cryptococcus gattii (C. gattii) genotype VGIIb was detected in the patient's sputum and cerebrospinal fluid specimens. The serum levels of anti-granulocyte-macrophage colony-stimulating factor (GM-CSF) antibodies were elevated in this patient, which has been associated with pulmonary alveolar proteinosis and is considered a risk factor for C. gattii infection. After undergoing >12 months of antifungal treatments, the patient showed improvements in symptoms and findings on brain and lung imaging. Several Japanese patients who develop C. gattii infection have also been reported; however, most of these patients have been infected outside Japan, as C. gattii infection is rare in Japan. Only one patient with C. gattii genotype VGIIb infection has been reported in Japan, and it is believed that this patient contracted the infection in China. In the present case, our patient has never been outside Japan, indicating that the infection originated in Japan. Our findings suggest that C. gattii might be spreading in Japan. Therefore, patients with positive serum anti-GM-CSF antibodies should be thoroughly monitored for C. gattii infection, even those living in Japan.

Global guideline for the diagnosis and management of cryptococcosis: an initiative of the ECMM and ISHAM in cooperation with the ASM

Cryptococcosis is a major worldwide disseminated invasive fungal infection. Cryptococcosis, particularly in its most lethal manifestation of cryptococcal meningitis, accounts for substantial mortality and morbidity. The breadth of the clinical cryptococcosis syndromes, the different patient types at-risk and affected, and the vastly disparate resource settings where clinicians practice pose a complex array of challenges. Expert contributors from diverse regions of the world have collated data, reviewed the evidence, and provided insightful guideline recommendations for health practitioners across the globe. This guideline offers updated practical guidance and implementable recommendations on the clinical approaches, screening, diagnosis, management, and follow-up care of a patient with cryptococcosis and serves as a comprehensive synthesis of current evidence on cryptococcosis. This Review seeks to facilitate optimal clinical decision making on cryptococcosis and addresses the myriad of clinical complications by incorporating data from historical and contemporary clinical trials. This guideline is grounded on a set of core management principles, while acknowledging the practical challenges of antifungal access and resource limitations faced by many clinicians and patients. More than 70 societies internationally have endorsed the content, structure, evidence, recommendation, and pragmatic wisdom of this global cryptococcosis guideline to inform clinicians about the past, present, and future of care for a patient with cryptococcosis.

Reframing the clinical phenotype and management of cryptococcal meningitis

Cryptococcal meningitis is an important global health problem, resulting from infection with the yeast Cryptococcus, especially Cryptococcus neoformans and Cryptococcus gattii, which cause a spectrum of disease ranging from pulmonary and skin lesions to life-threatening central nervous system involvement. The diagnosis and management of cryptococcal meningitis have substantially changed in recent years. Cryptococcal meningitis often occurs in people living with advanced HIV infection, though in high-income countries with robust HIV detection and treatment programmes, it increasingly occurs in other groups, notably solid-organ transplant recipients, other immunosuppressed patients and even immunocompetent hosts. This review outlines the clinical presentation, management and prognosis of cryptococcal meningitis, including its salient differences in people living with HIV compared with HIV-negative patients. We discuss the importance of managing raised intracranial pressure and highlight the advantages of improved multidisciplinary team working involving neurologists, infectious disease specialists and neurosurgeons.

Autoantibodies Neutralizing GM-CSF in HIV-Negative Colombian Patients Infected with Cryptococcus gattii and C. neoformans

BACKGROUND

Cryptococcosis is a life-threatening disease caused by Cryptococcus neoformans or C. gattii. Neutralizing autoantibodies (auto-Abs) against granulocyte-macrophage colony-stimulating factor (GM-CSF) in otherwise healthy adults with cryptococcal meningitis have been described since 2013. We searched for neutralizing auto-Abs in sera collected from Colombian patients with non-HIV-associated cryptococcosis in a retrospective national cohort from 1997 to 2016.

METHODS

We reviewed clinical and laboratory records and assessed the presence of neutralizing auto-Abs against GM-CSF in 30 HIV negative adults with cryptococcosis (13 caused by C. gattii and 17 caused by C. neoformans).

RESULTS

We detected neutralizing auto-Abs against GM-CSF in the sera of 10 out of 13 (77%) patients infected with C. gattii and one out of 17 (6%) patients infected with C. neoformans.

CONCLUSIONS

We report eleven Colombian patients diagnosed with cryptococcosis who had auto-Abs that neutralize GM-CSF. Among these patients, ten were infected with C. gattii and only one with C. neoformans.

Influence of the agrochemical benomyl on Cryptococcus gattii-plant interaction in vitro and in vivo

Cryptococcus gattii, an environmental fungus, is one of the agents of cryptococcosis. The influence of agrochemicals on fungal resistance to antifungals is widely discussed. However, the effects of benomyl (BEN) on fungal interaction with different hosts is still to be understood. Here we studied the influence of adaptation to BEN in the interaction with a plant model, phagocytes and with Tenebrio molitor. First, the strain C. gattii L24/01 non-adapted (NA), adapted (A) to BEN, and adapted with further culture on drug-free media (10p) interact with Nicotiana benthamiana, with a peak in the yeast burden on the 7th day post-inoculation. C. gattii L24/01 A and 10p provided lower fungal burden, but these strains increased cell diameter and capsular thickness after the interaction, together with decreased fungal growth. The strains NA and A showed reduced ergosterol levels, while 10p exhibited increased activity of laccase and urease. L24/01 A recovered from N. benthamiana was less engulfed by murine macrophages, with lower production of reactive oxygen species. This phenotype was accompanied by increased ability of this strain to grow inside macrophages. Otherwise, L24/01 A showed reduced virulence in the T. molitor larvae model. Here, we demonstrate that the exposure to BEN, and interaction with plants interfere in the morphophysiology and virulence of the C. gattii.

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.

Clinical treatment of cryptococcal meningitis: an evidence-based review on the emerging clinical data

Cryptococcal meningitis (CM) is a fatal fungal central nervous system (CNS) infection caused by Cryptococcus infecting the meninges and/or brain parenchyma, with fever, headache, neck stiffness, and visual disturbances as the primary clinical manifestations. Immunocompromised individuals with human immunodeficiency virus (HIV) infection or who have undergone organ transplantation, as well as immunocompetent people can both be susceptible to CM. Without treatment, patients with CM may have a mortality rate of up to 100% after hospital admission. Even after receiving therapy, CM patients may still suffer from problems such as difficulty to cure, poor prognosis, and high mortality. Therefore, timely and effective treatment is essential to improve the mortality and prognosis of CM patients. Currently, the clinical outcomes of CM are frequently unsatisfactory due to limited drug choices, severe adverse reactions, drug resistance, etc. Here, we review the research progress of CM treatment strategies and discuss the suitable options for managing CM, hoping to provide a reference for physicians to select the most appropriate treatment regimens for CM patients.

Studying Human Pathogenic Cryptococcus Gattii Lineages by Utilizing Simple Sequence Repeats to Create Diagnostic Markers and Analyzing Diversity

In this study, we compared the occurrence, relative abundance (RA), and density (RD) of simple sequence repeats (SSRs) among the lineages of human pathogenic Cryptococcus gattii using an in-silico approach to gain a deeper understanding of the structure and evolution of their genomes. C. gattii isolate MF34 showed the highest RA and RD of SSRs in both the genomic and transcriptomic sequences, followed by isolate WM276. In both the genomic (50%) and transcriptomic (65%) sequences, trinucleotide SSRs were the most common SSR class. A motif conservation study found that the isolates had stronger conservation (56.1%) of motifs, with isolate IND107 having the most (5.7%) unique motifs. We discovered the presence of SSRs in genes that are directly or indirectly associated with disease using gene enrichment analysis. Isolate-specific unique motifs identified in this study could be utilized as molecular probes for isolate identification. To improve genetic resources among C. gattii isolates, 6499 primers were developed. These genomic resources developed in this study could help with diversity analysis and the development of isolate-specific markers.

An improved expression and purification protocol enables the structural characterization of Mnt1, an antifungal target from Candida albicans

BACKGROUND

Candida albicans is one of the most prevalent fungi causing infections in the world. Mnt1 is a mannosyltransferase that participates in both the cell wall biogenesis and biofilm growth of C. albicans. While the cell wall performs crucial functions in pathogenesis, biofilm growth is correlated with sequestration of drugs by the extracellular matrix. Therefore, antifungals targeting CaMnt1 can compromise fungal development and potentially also render Candida susceptible to drug therapy. Despite its importance, CaMnt1 has not yet been purified to high standards and its biophysical properties are lacking.

RESULTS

We describe a new protocol to obtain high yield of recombinant CaMnt1 in Komagataella phaffii using methanol induction. The purified protein's identity was confirmed by MALDI-TOF/TOF mass spectroscopy. The Far-UV circular dichroism (CD) spectra demonstrate that the secondary structure of CaMnt1 is compatible with a protein formed by α-helices and β-sheets at pH 7.0. The fluorescence spectroscopy results show that the tertiary structure of CaMnt1 is pH-dependent, with a greater intensity of fluorescence emission at pH 7.0. Using our molecular modeling protocol, we depict for the first time the ternary complex of CaMnt1 bound to its two substrates, which has enabled the identification of residues involved in substrate specificity and catalytic reaction. Our results corroborate the hypothesis that Tyr209 stabilizes the formation of an oxocarbenium ion-like intermediate during nucleophilic attack of the acceptor sugar, opposing the double displacement mechanism proposed by other reports.

CONCLUSIONS

The methodology presented here can substantially improve the yield of recombinant CaMnt1 expressed in flask-grown yeasts. In addition, the structural characterization of the fungal mannosyltransferase presents novelties that can be exploited for new antifungal drug's development.

Clinical Characteristics of Patients with Cryptococcal Meningitis in Hokkaido: A Case Series

We retrospectively reviewed the medical histories, examination results, treatments, and prognoses of nine patients with cryptococcal meningitis who were diagnosed and treated at Hokkaido University Hospital and its affiliated hospitals over the past 10 years. Cryptococcal meningitis can develop even in immunocompetent hosts, and its prognosis is poor owing to diagnostic difficulties and delayed treatment. Although liposomal amphotericin B and oral 5-fluorocytosine are standard therapies, voriconazole or intraventricular administration of amphotericin B may also be considered treatment options for refractory patients. Some patients develop delayed exacerbations owing to immunological mechanisms that require steroid therapy.

Disseminated Cryptococcus neoformans infection involving multiple bones and lung in an immunocompetent patient: a case report

BACKGROUND

Cryptococcal osteomyelitis is a rare and potentially serious condition, typically encountered in individuals with compromised immune systems. This case underscores the unusual occurrence of disseminated Cryptococcosis in an immunocompetent person, involving multiple bones and lungs, with Cryptococcus neoformans identified as the causative agent.

CASE PRESENTATION

An Indonesian man, previously in good health, presented with a chief complaint of successive multiple bone pain lasting for more one month, without any prior history of trauma. Additionally, he reported a recent onset of fever. On physical examination, tenderness was observed in the left lateral chest wall and right iliac crest. Laboratory findings indicated mildly elevated inflammatory markers. A computed tomography (CT) scan of the chest revealed an ovoid solid nodule in the right lower lung and multifocal osteolytic lesions in the sternum, ribs, and humeral head. A magnetic resonance imaging (MRI) study of the sacrum showed multiple lesions in the bilateral iliac bone and the lower L4 vertebral body. Confirmation of Cryptococcal osteomyelitis involved a fine-needle biopsy and culture, identifying Cryptococcus neoformans in the aspirate. The patient responded positively to targeted antifungal treatments, leading to a gradual improvement in his condition.

CONCLUSIONS

This case emphasizes the need to consider Cryptococcus neoformans osteomyelitis in immunocompetent patients with bone pain. A definitive diagnosis involves a fine-needle biopsy for pathology and culture, and prompt initiation of appropriate antifungal treatment has proven effective in preventing mortality.

Molecular epidemiological investigation of Cryptococcus spp. carried by captive koalas (Phascolarctos cinereus) in Japan

Cryptococcus neoformans and Cryptococcus gattii cause cryptococcosis, a systemic mycosis that infects a wide range of species. Recent molecular biological investigations have allowed for the genotyping of these species, providing more detailed information on their pathogenicity and infection routes. Koalas (Phascolarctos cinereus) are frequently colonized by Cryptococcus spp., but molecular epidemiological studies have yet to be conducted in Japan. Here, we conducted multi-locus sequence typing (MLST) analysis on Cryptococcus spp. colonization isolates obtained from all koalas kept in seven parks across Japan. Out of 46 koalas examined, 10 (22%) were positive for C. gattii and 3 (6.5%) were positive for C. neoformans. All C. gattii isolates belonged to molecular type VGI and were either sequence type (ST) 51 or a novel ST, and all C. neoformans isolates belonged to molecular type VNI and ST23. Despite the frequent movement of koalas between parks, the STs were relatively park-specific, suggesting that the floor of the rearing barns is a source of infection and may act as a reservoir. MLST analysis confirmed that C. gattii was transported, established, and spread by koalas in areas where C. gattii was not originally present. MLST analysis is considered useful in assessing the pathogenicity and tracing the transmission routes of Cryptococcus spp. carried by koalas.IMPORTANCEThis is the first study to conduct a multi-locus sequence typing analysis on Cryptococcus spp. carried by captive koalas in Japan. Cryptococcosis remains a globally high-fatality fungal infection in humans, and captive koalas are known to carry a high percentage of Cryptococcus spp. Through this research, the molecular types and transmission routes of Cryptococcus spp. carried by koalas have been elucidated, revealing the potential role of enclosure flooring as a reservoir. It has been confirmed that Cryptococcus gattii, which is not endemic in Japan, has become established through koalas and is spreading to new individuals in Japan. This study is believed to provide valuable insights into koala conservation and contribute to the One Health approach for Cryptococcosis, a zoonotic infection.

Minimum inhibitory concentrations of antifungals against invasive isolates of Cryptococcus species worldwide: Global antifungal antimicrobial testing leadership and surveillance program, 2010-2020

This study examined the geographic distribution of minimum inhibitory concentrations (MICs) of antifungals against Cryptococcus isolates. Data were collected on the MICs of specific antifungals (amphotericin B, 5-flucytosine, fluconazole, voriconazole, posaconazole, and isavuconazole) against various Cryptococcus species for the period 2010 to 2020 from the Antimicrobial Testing Leadership and Surveillance database. Cryptococcus isolates were collected from samples of blood and cerebrospinal fluid (CSF) from patients hospitalized in different regions worldwide. We applied the epidemiological cutoff values (ECVs) of antifungals against various Cryptococcus species to distinguish wild-type (WT) from non-WT Cryptococcus isolates. A total of 395 isolates of Cryptococcus species cultured from blood (n = 201) or CSF (n = 194) were analyzed. C. grubii (n = 270), C. neoformans (n = 111), and C. gattii (n = 11) were the three predominant species causing bloodstream infections (BSI) or meningitis/meningoencephalitis (MME). The proportion of MICs above the ECV (1 mg/L) for amphotericin B among C. neoformans isolates was significantly lower than that among C. gattii isolates (MICs >0.5 mg/L; P < 0.001), as evaluated using the chi-square test. For most isolates of the three predominant Cryptococcus species, the MICs of new triazoles were ≤0.25 mg/L. The MICs of fluconazole and amphotericin B in the BSI/MME-causing Cryptococcus isolates collected from patients hospitalized in the Asia-Western Pacific region and Europe were significantly lower (i.e., the distributions were more leftward) than those in North America and Latin America. Ongoing monitoring of MIC data for important antifungals against cryptococcosis is crucial.

Cryptococcal meningitis in apparently immunocompetent patients

Cryptococcal meningitis (CM) is an invasive fungal disease that currently poses a threat to human health worldwide, with high morbidity and mortality, particularly in immunocompromised patients. Although CM mainly occurs in HIV-positive patients and other immunocompromised patients, it is also increasingly seen in seemingly immunocompetent hosts. The clinical characteristics of CM between immunocompromised and immunocompetent populations are different. However, few studies have focussed on CM in immunocompetent individuals. This review summarizes the clinical characteristics of apparently immunocompetent CM patients in terms of aetiology, immune pathogenesis, clinical presentation, laboratory data, imaging findings, treatment strategies and prognosis. It is of great significance to further understand the disease characteristics of CM, explore new treatment strategies and improve the prognosis of CM in immunocompetent individuals.

The Ecology of Non-Candida Yeasts and Dimorphic Fungi in Cetaceans: From Pathogenicity to Environmental and Global Health Implications

Cetaceans, which are integral to marine ecosystems, face escalating anthropogenic threats, including climate change and pollution, positioning them as critical sentinel species for ocean and human health. This review explores the neglected realm of non-Candida yeasts in cetaceans, addressing the gaps in the understanding of their prevalence, pathogenicity, and environmental impacts. By examining identified species such as Cryptococcus spp., Paracoccidioides spp., and several dimorphic fungi, this review emphasizes global prevalence, epidemiology and ecology, pathogenicity, and potential zoonotic implications. It also discusses the fine line between yeast commensalism and pathogenicity by considering environmental influences such as pollution, climate shifts, and immune suppression. Environmental impact discussions delve into how rising ocean temperatures and pollution can modify yeast mycobiota, potentially affecting marine host health and broader ecosystem dynamics. The cetacean's unique physiology and ecological niches are considered, highlighting potential impacts on behaviors, reproductive success, and survival rates. Identifying crucial knowledge gaps, the review calls for intensified research efforts, employing advanced molecular techniques to unravel the cetacean mycobiome. Systematic studies on yeast diversity, antifungal susceptibility, and their influence on environmental and ecosystem health are proposed, and the balance between commensal and pathogenic species emphasizes the significance of the One Health approach. In conclusion, as marine mammals face unprecedented challenges, unveiling non-Candida yeasts in cetaceans emerges as a critical endeavor with far-reaching implications for the conservation of marine ecosystems and for both animal and human public health.

Whole-genome shotgun sequencing unravels the influence of environmental microbial co-infections on the treatment efficacy for severe pediatric infectious diseases

Background

The microbiome plays a pivotal role in mediating immune deviation during the development of early-life viral infections. Recurrent infections in children are considered a risk factor for disease development. This study delves into the metagenomics of the microbiome in children suffering from severe infections, seeking to identify potential sources of these infections.

Aims

The aim of this study was to identify the specific microorganisms and factors that significantly influence the treatment duration in patients suffering from severe infections. We sought to understand how these microbial communities and other variables may affect the treatment duration and the use of antibiotics of these patients with severe infections.

Method

Whole-genome shotgun sequencing was conducted on samples collected from children aged 0-14 years with severe infections, admitted to the Pediatrics Department of Xiamen First Hospital. The Kraken2 algorithm was used for taxonomic identification from sequence reads, and linear mixed models were employed to identify significant microorganisms influencing treatment duration. Colwellia, Cryptococcus, and Citrobacter were found to significantly correlate with the duration of clinical treatment. Further analysis using propensity score matching (PSM) and rank-sum test identified clinical indicators significantly associated with the presence of these microorganisms.

Results

Using a linear mixed model after removed the outliers, we identified that the abundance of Colwellia, Cryptococcus, and Citrobacter significantly influences the treatment duration. The presence of these microorganisms is associated with a longer treatment duration for patients. Furthermore, these microorganisms were found to impact various clinical measures. Notably, an increase in hospitalization durations and medication costs was observed in patients with these microorganisms. In patients with Colwellia, Cryptococcus, and Citrobacter, we discover significant differences in platelets levels. We also find that in patients with Cryptococcus, white blood cells, hemoglobin, and neutrophils levels are lower.

Conclusion

These findings suggest that Colwellia, Cryptococcus, and Citrobacter, particularly Cryptococcus, could potentially contribute to the severity of infections observed in this cohort, possibly as co-infections. These microorganisms warrant further investigation into their pathogenic roles and mechanisms of action, as their presence in combination with disease-causing organisms may have a synergistic effect on disease severity. Understanding the interplay between these microorganisms and pathogenic agents could provide valuable insights into the complex nature of severe pediatric infections and guide the development of targeted therapeutic strategies.

Autoantibodies neutralizing GM-CSF in HIV-negative Colombian patients infected with Cryptococcus gattii and C. neoformans

Background

Cryptococcosis is a life-threatening disease caused by Cryptococcus neoformans or C. gattii. Autoantibodies (auto-Abs) neutralizing granulocyte-macrophage colony-stimulating factor (GM-CSF) in otherwise healthy adults with cryptococcal meningitis have been described since 2013. We searched for neutralizing auto-Abs in sera from Colombian patients with non-HIV related cryptococcosis in a retrospective national cohort collected from 1997 to 2016.

Methods

We reviewed clinical and laboratory records and assessed the presence of neutralizing auto-Abs in 30 HIV (-) adults presenting cryptococcosis (13 by C. gattii, and 17 by C. neoformans).

Results

We detected auto-Abs neutralizing GM-CSF in the plasma of 9 out of 13 (69%) patients infected with C. gattii and 1 out of 17 (6%) patients with C. neoformans.

Conclusions

We report ten Colombian patients with cryptococcosis due to auto-Abs neutralizing GM-CSF. Nine of the ten patients were infected with C. gattii, and only one with C. neoformans.

Trends in the Incidence of Disseminated Cryptococcosis in Japan: A Nationwide Observational Study, 2015-2021

BACKGROUND

Cryptococcus species can cause severe disseminated infections in immunocompromised hosts. This study investigated the epidemiological features and trends in disseminated cryptococcosis in Japan.

METHODS

We used publicly available Infectious Diseases Weekly Reports to obtain data on the incidence of disseminated cryptococcosis in Japan from 2015 to 2021. Patient information, including age, sex, and regional and seasonal data, were extracted. The Joinpoint regression program was used to determine the age-adjusted incidence rate (AAR) per 100,000 population, annual percentage change (APC), and average APC (AAPC).

RESULTS

A total of 1047 cases of disseminated cryptococcosis were reported, of which those aged ≥ 70 years accounted for 68.8%. The AAR in men was significantly higher than that in women (median: 0.13 vs. 0.09: p = 0.0024). APC for the overall cases increased by 9.9% (95% confidence interval [95% CI] - 5.4-27.7) from 2015 to 2018 and then decreased by 3.3% (95% CI - 15.5-10.7) from 2018 to 2021. AAPC for the entire study period was 3.1% (95% CI - 1.5-8.0), indicating a possible increase in its number, although not statistically significant. In terms of regional distribution, the average AAR was highest in Shikoku District (0.17) and lowest in Hokkaido District (0.04). Northern Japan exhibited a significantly lower median AAR (median [interquartile range]: 0.06 [0.05, 0.08]) than the Eastern (0.12 [0.12, 0.13]), Western (0.11 [0.10, 0.13]), and Southern (0.14 [0.12, 0.15]) regions. No seasonal variation in incidence was observed.

CONCLUSION

The prevalence of disseminated cryptococcosis has not increased in Japan. Geographically, the incidence is lower in Northern Japan. Further investigations that incorporate detailed clinical data are required.

Proteomic profile of Cryptococcus gattii biofilm: Metabolic shift and the potential activation of electron chain transport

Cryptococcus gattii is a primary pathogenic fungus that causes pneumonia. This species is also responsible for an outbreak in Vancouver, Canada, and spreading to the mainland and United States. The use of medical devices is often complicated by infections with biofilm-forming microbes with increased resistance to antimicrobial agents and host defense mechanisms. This study investigated the comparative proteome of C. gattii R265 (VGIIa) grown under planktonic and biofilm conditions. A brief comparison with C. neoformans H99 biofilm and the use of different culture medium and surface were also evaluated. Using Multidimensional Protein Identification Technology (MudPIT), 1819 proteins were identified for both conditions, where 150 (8.2%) were considered differentially regulated (up- or down-regulated and unique in biofilm cells). Overall, the proteomic approach suggests that C. gattii R265 biofilm cells are maintained by the induction of electron transport chain for reoxidation, and by alternative energy metabolites, such as succinate and acetate. SIGNIFICANCE: Since C. gattii is considered a primary pathogen and is one of the most virulent and less susceptible to antifungals, understanding how biofilms are maintained is fundamental to search for new targets to control this important mode of growth that is difficult to eradicate.

Virulence profiling of Cryptococcus gattii isolates in China: insights from a multi-center study

IMPORTANCE

Our study indicates that the molecular typing of Cryptococcus gattii is unrelated to virulence. The integration of animal experiments and clinical prognosis demonstrated that pathogenicity did not exhibit a direct correlation with in vitro virulence phenotypes or molecular genotypes, emphasizing the intricate nature of virulence. In conclusion, our research holds the potential to provide valuable insights into understanding the microbiological attributes of C. gattii in China.

Finger-Prick Whole Blood Cryptococcal Antigen Lateral Flow Assay for the Diagnosis of Cryptococcosis in HIV-Negative Patients: A Case Series Study in Two Tertiary Centers in São Paulo, Brazil

Cryptococcosis in HIV-negative patients can be an opportunistic or endemic disease. There are no published studies on the use of the finger-prick whole blood (point-of-care) cryptococcal antigen lateral flow assay (CrAg LFA) for diagnosing cryptococcosis in HIV-negative patients. We conducted a case series study of HIV-negative patients with cryptococcosis in two centers in São Paulo, Brazil. The objectives were to identify the sensitivity of a finger-prick whole blood CrAg LFA and to describe the main characteristics of this population. We identified 30 HIV-negative patients with cryptococcosis [19 (63%), male; median age, 47 years]. Ten (33%) patients were immunosuppressed, ten (33%) had other comorbidities, and ten (33%) were apparently immunocompetent and without comorbidities. The distribution of the sites of cryptococcosis was as follows: the central nervous system, 90% (n = 27); pulmonary, 43% (n = 13); and other extrapulmonary sites, 40% (n = 12). The sensitivity of the finger-prick whole blood CrAg LFA for the diagnosis of cryptococcosis was 97% (29/30). Among 26 participants with cryptococcal meningitis, the sensitivity of testing cerebrospinal fluid was as follows: CrAg latex agglutination, 77% (20/26); CrAg LFA, 96% (25/26); and culture, 81% (21/26). Culture speciation identified Cryptococcus gattii in 16 (62%) cases, and all had a positive finger-prick whole blood CrAg LFA. This test presented high sensitivity to the diagnosis of cryptococcosis in HIV-negative patients, including those caused by C. gattii.

Cryptococcal meningitis

Cryptococcus neoformans and Cryptococcus gattii species complexes cause meningoencephalitis with high fatality rates and considerable morbidity, particularly in persons with deficient T cell-mediated immunity, most commonly affecting people living with HIV. Whereas the global incidence of HIV-associated cryptococcal meningitis (HIV-CM) has decreased over the past decade, cryptococcosis still accounts for one in five AIDS-related deaths globally due to the persistent burden of advanced HIV disease. Moreover, mortality remains high (~50%) in low-resource settings. The armamentarium to decrease cryptococcosis-associated mortality is expanding: cryptococcal antigen screening in the serum and pre-emptive azole therapy for cryptococcal antigenaemia are well established, whereas enhanced pre-emptive combination treatment regimens to improve survival of persons with cryptococcal antigenaemia are in clinical trials. Short courses (≤7 days) of amphotericin-based therapy combined with flucytosine are currently the preferred options for induction therapy of cryptococcal meningitis. Whether short-course induction regimens improve long-term morbidity such as depression, reduced neurocognitive performance and physical disability among survivors is the subject of further study. Here, we discuss underlying immunology, changing epidemiology, and updates on the management of cryptococcal meningitis with emphasis on HIV-associated disease.

Cryptococcal Meningoencephalitis in Phenotypically Normal Patients

Cryptococcosis is an invasive fungal infection found worldwide that causes significant morbidity and mortality among a broad range of hosts. There are approximately 223,000 new cases of cryptococcosis annually throughout the world, and at least 180,000 deaths are attributed to this infection each year. Most of these are due to complications of cryptococcal meningoencephalitis among HIV-infected patients in resource-limited environments. The majority of individuals diagnosed with cryptococcosis have underlying conditions associated with immune dysfunction such as HIV, solid organ transplant, hematologic malignancy, organ failure syndromes, and/or the use of immunosuppressive agents such as glucocorticosteroids and biologic agents. In most clinical series, there is a small proportion of patients with cryptococcosis who are phenotypically normal; that is, they have no clinically obvious predisposition to disease. Cryptococcal meningoencephalitis (CME) presentation and management differ substantially between these normal individuals and their immunocompromised counterparts. In this review, we will focus on CME in the phenotypically normal host and underscore differences in the clinical presentation, management, outcome, and potential risk factors for these patients compared to immunocompromised persons who develop this potential devastating invasive fungal infection.

Diabetes Mellitus Type 2 as a Risk Factor and Outcome Modifier for Cryptococcosis in HIV Negative, Non-transplant Patients, a Propensity Score Match Analysis

Cryptococcosis is an opportunistic fungal infection of worldwide distribution with significant associated morbidity and mortality. HIV, organ transplantation, malignancy, cirrhosis, sarcoidosis, and immunosuppressive medications are established risk factors for cryptococcosis. Type 2 diabetes mellitus (DM2) has been hypothesized as a risk factor and an outcome modifier for cryptococcosis. We aimed to compare outcomes among HIV-negative, non-transplant (NHNT) patients with and without DM2. We queried a global research network to identify NHNT patients (n = 3280). We performed a propensity score-matched (PSM) analysis comparing clinical outcomes among cryptococcosis patients by DM status. We also characterize adults with cryptococcosis and DM2 as the only risk factor. After PSM, NHNT patients with DM2 were more likely to develop cognitive dysfunction [9% vs. 6%, OR 1.6; 95% CI (1.1-2.3); P = 0.01] but had similar mortality, hospitalization, ICU, and stroke risk after acquiring cryptococcosis when compared to NHNT patients without DM2. Pulmonary cryptococcosis was the most common site of infection. Among 44 cryptococcosis patients with DM2 as the only identifiable risk factor for disease, the annual incidence of cryptococcosis was 0.001%, with a prevalence of 0.002%. DM2 is associated with increased cognitive dysfunction risk in NHNT patients with cryptococcosis. It is rare for DM2 to be the only identified risk factor for developing cryptococcosis. Kidney disease, hyperglycemia, and immune dysfunction can increase the risk of cryptococcosis in patients with DM2.

Current Epidemiology and Clinical Features of Cryptococcus Infection in Patients Without Human Immunodeficiency Virus: A Multicenter Study in 46 Hospitals in Australia and New Zealand

BACKGROUND

Patients without human immunodeficiency virus (HIV) are increasingly recognized as being at risk for cryptococcosis. Knowledge of characteristics of cryptococcosis in these patients remains incomplete.

METHODS

We conducted a retrospective study of cryptococcosis in 46 Australian and New Zealand hospitals to compare its frequency in patients with and without HIV and describe its characteristics in patients without HIV. Patients with cryptococcosis between January 2015 and December 2019 were included.

RESULTS

Of 475 patients with cryptococcosis, 90% were without HIV (426 of 475) with marked predominance in both Cryptococcus neoformans (88.7%) and Cryptococcus gattii cases (94.3%). Most patients without HIV (60.8%) had a known immunocompromising condition: cancer (n = 91), organ transplantation (n = 81), or other immunocompromising condition (n = 97). Cryptococcosis presented as incidental imaging findings in 16.4% of patients (70 of 426). The serum cryptococcal antigen test was positive in 85.1% of tested patients (319 of 375); high titers independently predicted risk of central nervous system involvement. Lumbar puncture was performed in 167 patients to screen for asymptomatic meningitis, with a positivity rate of 13.2% where meningitis could have been predicted by a high serum cryptococcal antigen titer and/or fungemia in 95% of evaluable cases. One-year all-cause mortality was 20.9% in patients without HIV and 21.7% in patients with HIV (P = .89).

CONCLUSIONS

Ninety percent of cryptococcosis cases occurred in patients without HIV (89% and 94% for C. neoformans and C. gattii, respectively). Emerging patient risk groups were evident. A high level of awareness is warranted to diagnose cryptococcosis in patients without HIV.

Genotyping Analysis of Cryptococcus deuterogattii and Correlation with Virulence Factors and Antifungal Susceptibility by the Clinical and Laboratory Standards Institute and the European Committee on Antifungal Susceptibility Testing Methods

Data about the relationship between their molecular types, virulence factors, clinical presentation, antifungal susceptibility profile, and outcome are still limited for Cryptococcus deuterogattii. This study aimed to evaluate the molecular and phenotypic characteristics of 24 C. deuterogattii isolates from the southeast region of Brazil. The molecular characterization was performed by multilocus sequence typing (MLST). The antifungal susceptibility profile was obtained according to CLSI-M27-A3 and EUCAST-EDef 7.1 methods. The virulence factors were evaluated using classic techniques. The isolates were divided into four populations. The molecular analysis suggests recombinant events in most of the groups evaluated. Resistance and susceptibility dose-dependent to fluconazole were evidenced in four isolates (16%) by EUCAST and in four isolates (16%) by CLSI methods. The agreement at ±two dilutions for both methods was 100% for itraconazole, ketoconazole, and voriconazole, 96% for amphotericin B, and 92% for fluconazole. Significant differences in virulence factor expression and antifungal susceptibility to itraconazole and amphotericin B were found. The mixed infection could be suggested by the presence of variable sequence types, differences in virulence factor production, and decreased antifungal susceptibility in two isolates from the same patient. The data presented herein corroborate previous reports about the molecular diversity of C. deuterogattii around the world.

Reduced Susceptibility to Azoles in Cryptococcus gattii Correlates with the Substitution R258L in a Substrate Recognition Site of the Lanosterol 14-α-Demethylase

Cryptococcus neoformans and Cryptococcus gattii cause cryptococcosis, a life-threatening fungal infection affecting mostly immunocompromised patients. In fact, cryptococcal meningitis accounts for about 19% of AIDS-related deaths in the world. Because of long-term azole therapies to treat this mycosis, resistance to fluconazole leading to treatment failure and poor prognosis has long been reported for both fungal species. Among the mechanisms implicated in resistance to azoles, mutations in the ERG11 gene, encoding the azole target enzyme lanosterol 14-α-demethylase, have been described. This study aimed to establish the amino acid composition of ERG11 of Colombian clinical isolates of C. neoformans and C. gattii and to correlate any possible substitution with the in vitro susceptibility profile of the isolates to fluconazole, voriconazole, and itraconazole. Antifungal susceptibility testing results showed that C. gattii isolates are less susceptible to azoles than C. neoformans isolates, which could correlate with differences in the amino acid composition and structure of ERG11 of each species. In addition, in a C. gattii isolate with high MICs for fluconazole (64 μg/mL) and voriconazole (1 μg/mL), a G973T mutation resulting in the substitution R258L, located in substrate recognition site 3 of ERG11, was identified. This finding suggests the association of the newly reported substitution with the azole resistance phenotype in C. gattii. Further investigations are needed to determine the exact role that R258L plays in the decreased susceptibility to fluconazole and voriconazole, as well as to determine the participation of additional mechanisms of resistance to azole drugs. IMPORTANCE The fungal species Cryptococcus neoformans and C. gattii are human pathogens for which drug resistance or other treatment and management challenges exist. Here, we report differential susceptibility to azoles among both species, with some isolates displaying resistant phenotypes. Azoles are among the most commonly used drugs to treat cryptococcal infections. Our findings underscore the necessity of testing antifungal susceptibility in the clinical setting in order to assist patient management and beneficial outcomes. In addition, we report an amino acid change in the sequence of the target protein of azoles, which suggests that this change might be implicated in resistance to these drugs. Identifying and understanding possible mechanisms that affect drug affinity will eventually aid the design of new drugs that overcome the global growing concern of antifungal resistance.

Post-infectious inflammatory response syndrome in an HIV-negative patient after Cryptococcus gattii meningoencephalitis: a case report and review of the literature

BACKGROUND

Cryptococcal meningitis (CM) is an inflammatory mycosis of the central nervous system caused by meninge infection or brain parenchyma with Cryptococcus species. It is associated with high morbidity and mortality, and patients with acquired immune deficiency syndrome are particularly susceptible. There have been increasing reports of CM in HIV-negative patients in China over the last few years.

CASE PRESENTATION

A 31-year-old healthy Chinese male presented with fever and gradually developed headache, projectile vomiting, and other manifestations that were later confirmed as Cryptococcus gattii meningoencephalitis. However, multiple disease changes occurred during the course of treatment, and the regimen was accordingly modified after the diagnosis of post-infectious inflammatory response syndrome (PIIRS). The patient eventually recovered.

CONCLUSION

There has been a growing trend in the incidence of C. gattii meningoencephalitis in HIV-negative patients. It shows rapid onset and severe prognosis. This case report can provide a reference to treat PIIRS following CM in HIV-negative patients.

Cryptococcal Meningitis in Young, Immunocompetent Patients: A Single-Center Retrospective Case Series and Review of the Literature

Background

Cryptococcal meningitis is an uncommon but serious infection with high mortality and morbidity. Classically described in immunocompromised patients, including those with solid organ transplants or HIV/AIDS, cryptococcosis has also been reported in young and otherwise healthy patients, albeit rarely.

Methods

We retrospectively searched for all cases of cryptococcal meningitis in young (≤50 years) and previously healthy patients with no known immunocompromising conditions from January 2015 to January 2022 at Indiana University Health (IU Health). Additionally, a PubMed literature review was performed with the keywords "cryptococcal meningitis" and "immunocompetent" from January 1988 to January 2022. Clinical courses, including outcomes and treatment regimens, were evaluated.

Results

We identified 4 local cases of cryptococcal meningitis in otherwise healthy patients age ≤50 years. Three cases were due to Cryptococcus neoformans, with 1 experiencing a postinfectious inflammatory response syndrome (PIIRS). The PubMed search identified 51 additional cases, with 32 (63%) being caused by Cryptococcus neoformans and 8 (17%) by Cryptococcus gattii. Of the 51 cases, only 2 resulted in death directly due to cryptococcosis. Fifteen (29%) had PIIRS, with steroid treatment documented in 11 of 15. Antifungal induction regimens and duration were varied but predominately consisted of amphotericin and flucytosine, with a mean induction duration of 5.0 weeks.

Conclusions

Cryptococcal meningitis in young, previously healthy patients is likely under-recognized. PIIRS (akin to immune reconstitution inflammatory syndrome observed in HIV/AIDS) with prolonged recovery should be of concern. Determining risk factors for cryptococcosis in these patients remains elusive.

Staphylococcus aureus triggers a protective inflammatory response against secondary Cryptococcus gattii infection in a murine model

Prior infections can provide protection or enhance susceptibility to a subsequent infection through microorganism's interaction or host immunomodulation. Staphylococcus aureus (SA) and Cryptococcus gattii (CG) cause lungs infection, but it is unclear how they interact in vivo. This study aimed to study the effects of the primary SA lung infection on secondary cryptococcosis caused by CG in a murine model. The mice's survival, fungal burden, behavior, immune cells, cytokines, and chemokines were quantified to evaluate murine cryptococcosis under the influence of a previous SA infection. Further, fungal-bacterial in vitro interaction was studied in a culture medium and a phagocytosis assay. The primary infection with SA protects animals from the subsequent CG infection by reducing lethality, improving behavior, and impairing the fungal proliferation within the host. This phenotype was associated with the proinflammatory antifungal host response elicited by the bacteria in the early stage of cryptococcosis. There was no direct inhibition of CG by SA, although the phagocytic activity of macrophages was reduced. Identifying mechanisms involved in this protection may lead to new approaches for preventing and treating cryptococcosis.

Neurological worsening during treatment of HIV-negative cryptococcal meningitis in a patient with Evans syndrome

A 49-year-old woman with a rare autoimmune hematological disease, Evans syndrome, was admitted to the authors' hospital with immune reconstitution inflammatory syndrome-like reconstitution syndrome after effective antifungal therapy for cryptococcal meningitis. She initially improved after receiving corticosteroid treatment; after prednisone was tapered, her clinical presentation and brain imaging deteriorated but finally improved with the addition of thalidomide. Immune reconstitution inflammatory syndrome-like reconstitution syndrome is a rare complication in cryptococcal meningitis patients receiving immunosuppressive therapy. Thalidomide can be given in addition to corticosteroid therapy to effectively control the paradoxical inflammatory response and improve clinical outcomes.

Fluconazole Resistance and Virulence in In Vitro Induced-Fluconazole Resistant Strains and in Clinical Fluconazole Resistant Strain of Cryptococcus deuterogattii

Neuromeningeal cryptococcosis is a life-threatening infection of the central nervous system, caused by encapsulated yeast belonging to the Cryptococcus neoformans and Cryptococcus gattii species complexes. Recent data showed that virulence and antifungal resistance are variable for yeasts belonging to the C. gattii species complex. There is an increase in resistance to fluconazole for yeasts of the C. gattii species complex and the virulence is variable according to the genotype. In the present study, (i) we explored and compared the mechanisms of resistance to fluconazole between C. deuterogattii clinically resistant strains and induced fluconazole-resistant strains by exposure to fluconazole in vitro, and (ii) we studied their virulence in the Galleria mellonella study model. We demonstrated that the fluconazole resistance mechanisms involved were different between clinically resistant strains and induced resistant strains. We also demonstrated that fluconazole-induced resistant strains are less virulent when compared to the original susceptible strains. On the contrary, the clinically resistant strain tested maintains its virulence compared to fluconazole-susceptible strains of the same sequence type.

Disseminated Cryptococcosis Revealing an HIV Infection: A Case Report

Cryptococcosis is a common fungal infection regarded as a disease of immunocompromised patients with high mortality. Cryptococcosis is usually observed in the central nervous system and lungs. However, other organs may be involved such as skin, soft tissue, and bones. Disseminated cryptococcosis is defined as fungemia or the involvement of two distinct sites. Here, we report the case of a 31-year-old female patient with disseminated cryptococcosis with neuro-meningeal and pulmonary involvement revealing a human immunodeficiency virus (HIV) infection. Chest computed tomography scan showed a right apical excavated lesion, pulmonary nodules, and mediastinal lymphadenopathy. Concerning biological tests, hemoculture, sputum, and cerebrospinal fluid (CSF) culture were positive for Cryptococcus neoformans. The latex agglutination test for cryptococcal polysaccharide antigen was positive in CSF and serum and HIV infection was confirmed by serological testing. The patient did not respond to initial antifungal therapy with amphotericin B and flucytosine. Despite the adaptation of antifungal treatment, the patient died of respiratory distress.

Cryptococcal Meningitis: Differences between Patients with and without HIV-Infection

Background: Cryptococcal meningitis is one of the most devastating infections, particularly in HIV-infected individuals. The increased use of immunosuppressants led to an increase in the incidence of cryptococcosis in HIV-uninfected individuals. This study aimed to compare the characteristics between groups. Methods: This retrospective cohort study was conducted from 2011 to 2021 in northern Thailand. Individuals diagnosed with cryptococcal meningitis aged ≥15 years were enrolled onto the study. Results: Out of 147 patients, 101 were individuals infected with HIV and 46 were non-infected. Factors associated with being infected with HIV included age < 45 years (OR 8.70, 95% CI 1.78–42.62), white blood cells < 5000 cells/cu.mm. (OR 7.18, 95% CI 1.45–35.61), and presence of fungemia (OR 5.86, 95% CI 1.17–42.62). Overall, the mortality rate was 24% (18% in HIV-infected vs. 37% in HIV-uninfected individuals, p-value = 0.020). Factors associated with mortality included concurrent pneumocystis pneumonia (HR 5.44, 95% CI 1.55–19.15), presence of alteration of consciousness (HR 2.94, 95% CI 1.42–6.10), infection caused by members of C. gattii species complex (HR 4.19, 95% CI 1.39–12.62), and anemia (HR 3.17, 95% CI 1.17–8.59). Conclusions: Clinical manifestations of cryptococcal meningitis differed between patients with and without HIV-infection in some aspects. Increasing awareness in physicians of this disease in HIV-uninfected individuals may prompt earlier diagnosis and timely treatment.

Epidemiology, management and outcomes of Cryptococcus gattii infections: A 22-year cohort

BACKGROUND

Cryptococcus gattii is a globally endemic pathogen causing disease in apparently immune-competent hosts. We describe a 22-year cohort study from Australia's Northern Territory to evaluate trends in epidemiology and management, and outcome predictors.

METHODS

A retrospective cohort study of all C. gattii infections at the northern Australian referral hospital 1996-2018 was conducted. Cases were defined as confirmed (culture-positive) or probable. Demographic, clinical and outcome data were extracted from medical records.

RESULTS

45 individuals with C. gattii infection were included: 44 Aboriginal Australians; 35 with confirmed infection; none HIV positive out of 38 tested. Multifocal disease (pulmonary and central nervous system) occurred in 20/45 (44%). Nine people (20%) died within 12 months of diagnosis, five attributed directly to C. gattii. Significant residual disability was evident in 4/36 (11%) survivors. Predictors of mortality included: treatment before the year 2002 (4/11 versus 1/34); interruption to induction therapy (2/8 versus 3/37) and end-stage kidney disease (2/5 versus 3/40). Prolonged antifungal therapy was the standard approach in this cohort, with median treatment duration being 425 days (IQR 166-715). Ten individuals had adjunctive lung resection surgery for large pulmonary cryptococcomas (median diameter 6cm [range 2.2-10cm], versus 2.8cm [1.2-9cm] in those managed non-operatively). One died post-operatively, and 7 had thoracic surgical complications, but ultimately 9/10 (90%) treated surgically were cured compared with 10/15 (67%) who did not have lung surgery. Four patients were diagnosed with immune reconstitution inflammatory syndrome which was associated with age <40 years, brain cryptococcomas, high cerebrospinal fluid pressure, and serum cryptococcal antigen titre >1:512.

CONCLUSION

C. gattii infection remains a challenging condition but treatment outcomes have significantly improved over 2 decades, with eradication of infection the norm. Adjunctive surgery for the management of bulky pulmonary C. gattii infection appears to increase the likelihood of durable cure and likely reduces the required duration of antifungal therapy.

Factors Influencing the Nitrogen-Source Dependent Flucytosine Resistance in Cryptococcus Species

Flucytosine (5-FC) is an antifungal agent commonly used for treatment of cryptococcosis and several other systemic mycoses. In fungi, cytosine permease and cytosine deaminase are known major players in flucytosine resistance by regulating uptake and deamination of 5-FC, respectively. Cryptococcus species have three paralogs each of cytosine permease (FCY2, FCY3, and FCY4) and cytosine deaminase (FCY1, FCY5 and FCY6). As in other fungi, we found FCY1 and FCY2 to be the primary cytosine deaminase and permease gene, respectively, in C. neoformans H99 (VNI), C. gattii R265 (VGIIa) and WM276 (VGI). However, when various amino acids were used as the sole nitrogen source, C. neoformans and C. gattii diverged in the function of FCY3 and FCY6. Though there was some lineage-dependent variability, the two genes functioned as the secondary permease and deaminase, respectively, only in C. gattii when the nitrogen source was arginine, asparagine, or proline. Additionally, the expression of FCY genes, excluding FCY1, was under nitrogen catabolic repression in the presence of NH₄. Functional analysis of GAT1 and CIR1 gene deletion constructs demonstrated that these two genes regulate the expression of each permease and deaminase genes individually. Furthermore, the expression levels of FCY3 and FCY6 under different amino acids corroborated the 5-FC susceptibility in fcy2Δ or fcy1Δ background. Thus, the mechanism of 5-FC resistance in C. gattii under diverse nitrogen conditions is orchestrated by two transcription factors of GATA family, cytosine permease and deaminase genes. IMPORTANCE 5-FC is a commonly used antifungal drug for treatment of cryptococcosis caused by Cryptococcus neoformans and C. gattii species complexes. When various amino acids were used as the sole nitrogen source for growth, we found lineage dependent differences in 5-FC susceptibility. Deletion of the classical cytosine permease (FCY2) and deaminase (FCY1) genes caused increased 5-FC resistance in all tested nitrogen sources in C. neoformans but not in C. gattii. Furthermore, we demonstrate that the two GATA family transcription factor genes GAT1 and CIR1 are involved in the nitrogen-source dependent 5-FC resistance by regulating the expression of the paralogs of cytosine permease and deaminase genes. Our study not only identifies the new function of paralogs of the cytosine permease and deaminase and the role of their regulatory transcription factors but also denotes the differences in the mechanism of 5-FC resistance among the two etiologic agents of cryptococcosis under different nitrogen sources.

Emerging and re-emerging fungal threats in Africa

The emergence of deadly fungal infections in Africa is primarily driven by a disproportionately high burden of human immunodeficiency virus (HIV) infections, lack of access to quality health care, and the unavailability of effective antifungal drugs. Immunocompromised people in Africa are therefore at high risk of infection from opportunistic fungal pathogens such as Cryptococcus neoformans and Pneumocystis jirovecii, which are associated with high morbidity, mortality, and related socioeconomic impacts. Other emerging fungal threats include Emergomyces spp., Histoplasma spp., Blastomyces spp., and healthcare-associated multi-drug resistant Candida auris. Socioeconomic development and the Covid-19 pandemic may influence shifts in epidemiology of invasive fungal diseases on the continent. This review discusses the epidemiology, clinical manifestations, and current management strategies available for these emerging fungal diseases in Africa. We also discuss gaps in knowledge, policy, and research to inform future efforts at managing these fungal threats.

Genotypic Diversity and Antifungal Susceptibility of Clinical Isolates of Cryptococcus Gattii Species Complex from Argentina

The aim of this study was to determine the genotypic diversity of 22 Cryptococcus gattii species complex clinical isolates from Argentina and to place these genotypes within the diversity of clinical, veterinary and environmental isolates from Latin America. Mating type and antifungal susceptibility of the isolates were also determined. By URA5-RFLP, nine isolates were identified as molecular type VGI, 10 as VGII, one as VGIII and two as VGIV. Multilocus sequence typing (MSLT), following the International Society for Human and Animal Mycology (ISHAM) consensus MLST scheme, was used to determine the genotypic diversity. Our results suggest that, in Argentina, VGI isolates have low genetic diversity, while VGII isolates have high genetic diversity. Both isolates identified as VGIV by URA5-RFLP were genotyped by MLST as belonging to the currently named VGVI clade. From all isolates, eight sequence types (STs) were unique for Argentina, while five STs have been reported already in other countries, being of high interest the genotypes ST20 and ST7 since they belong to the subtypes VGIIa and VGIIb, respectively, which are associated with hypervirulent strains responsible for outbreaks in North America. To note, geographical analysis showed that some genotypes may be associated with some regions in Argentina. Most isolates were MATα, but we are reporting one isolate MATa for the first time in the country. Antifungal susceptibility tests showed that itraconazole, voriconazole and posaconazole had high activity against all isolates, while amphotericin B, fluconazole and 5-fluorocytosine were the least active drugs against all studied isolates.

Cryptococcal infection causing longitudinal extensive transverse myelitis in an immunocompetent individual: Case report and literature review

Cryptococcal CNS infections in immunocompetent individuals are occasionally reported in literature. The spinal manifestations of cryptococcal CNS infections are epidural abscess, chronic arachnoiditis, intramedullary granuloma, myelitis and vasculitis. We report a rare case of CNS cryptococcal infection presenting as a longitudinal extensive transverse myelitis (LETM) in an immunocompetent male. This report highlights cryptococcus as an important etiology among infectious causes in acute LETM patients in-spite of the immunocompetent status of the patient and the utility of CRAG (cryptococcal antigen) for diagnosis in such patients. We also present a literature review of all reported cases of cryptococcal myelitis.

Effects of combination of Cryptococcus gattii and IFN-γ, IL-4 or IL-27 on human bronchial epithelial cells

BACKGROUND

Airway epithelial cells are crucial for the establishment of cryptococcosis. In experimental cryptococcosis, the Th2 immune response is associated with host susceptibility, while Th1 cells are associated with protection. The absence of IL-27 receptor alpha in mice favor the increase Cryptococcus neoformans burden in the lung. Here, we evaluated the effects of the combination of IL-4, IFN-γ or IL-27 with C. gattii on human bronchial epithelial cells (BEAS-2B).

METHODS

BEAS-2B were stimulated with IL-4, IFN-γ or IL-27 (100 ng/mL) and/or live yeast forms of C. gattii (multiplicities of infection (MOI) of 1-100) and vice-versa, as well as with heat-killed cells of C. gattii for 24 h.

RESULTS

None of the C. gattii MOIs had cytotoxic effects on BEAS-2B when compared to control. The cells stimulated by cytokines (IL-4, IFN-γ or IL-27) followed by live yeast forms of C. gattii (MOI of 100) infection and vice-versa demonstrated a reduction in IL-6, IL-8 and/or CCL2 production and activation of STAT6 (induced by IL-4) and STAT1 (induced by IL-27 or IFN-γ) when compared to cells stimulated with C. gattii, IL-4, IFN-γ or IL-27. In the combination of cytokines and heat-killed cells of C. gattii, no inhibition of these inflammatory parameters was observed. The growth of C. gattii was increased while the phagocytosis of live yeast forms of C. gattii in the BEAS-2B were reduced in the presence of IL-4, IFN-γ or IL-27. Conclusion The association of live yeast forms, but not heat-killed yeast forms, of C. gattii with IL-4, IFN-γ or IL-27 induced an anti-inflammatory effect.

Diagnostic and therapeutic approach to chronic meningitis in Brazil: a narrative review

BACKGROUND

Chronic meningitis (CM) is characterized by neurological symptoms associated with the evidence of cerebrospinal fluid pleocytosis lasting > 4 weeks. Studies on the management of CM in Brazil are scarce.

OBJECTIVE

To critically review the literature on CM and propose a rational approach in the Brazilian scenario.

METHODS

Narrative literature review discussing the epidemiology, clinical evaluation, basic and advanced diagnostic testing, and empirical and targeted therapy for the most relevant causes of CM. The present review was contextualized with the local experience of the authors. In addition, we propose an algorithm for the management of CM in Brazil.

RESULTS

In Brazil, tuberculosis and cryptococcosis are endemic and should always be considered in CM patients. In addition to these diseases, neurosyphilis and other endemic conditions should be included in the differential diagnosis, including neurocysticercosis, Baggio-Yoshinari syndrome, and endemic mycosis. After infectious etiologies, meningeal carcinomatosis and autoimmune diseases should be considered. Unbiased and targeted methods should be used based on availability and clinical and epidemiological data.

CONCLUSION

We propose a rational approach to CM in Brazil, considering the epidemiological scenario, systematizing the etiological investigation, and evaluating the timely use of empirical therapies.

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.

The Cryptococcus gattii species complex: Unique pathogenic yeasts with understudied virulence mechanisms

Members of Cryptococcus gattii/neoformans species complex are the etiological agents of the potentially fatal human fungal infection cryptococcosis. C. gattii and its sister species cause disease in both immunocompetent and immunocompromised hosts, while the closely related species C. neoformans and C. deneoformans predominantly infect immunocompromised hosts. To date, most studies have focused on similarities in pathogenesis between these two groups, but over recent years, important differences have become apparent. In this review paper, we highlight some of the major phenotypic differences between the C. gattii and neoformans species complexes and justify the need to study the virulence and pathogenicity of the C. gattii species complex as a distinct cryptococcal group.

The Dynamics of Cryptococcus neoformans Cell and Transcriptional Remodeling during Infection

The phenotypic plasticity of Cryptococcus neoformans is widely studied and demonstrated in vitro, but its influence on pathogenicity remains unclear. In this study, we investigated the dynamics of cryptococcal cell and transcriptional remodeling during pulmonary infection in a murine model. We showed that in Cryptococcus neoformans, cell size reduction (cell body ≤ 3 µm) is important for initial adaptation during infection. This change was associated with reproductive fitness and tissue invasion. Subsequently, the fungus develops mechanisms aimed at resistance to the host’s immune response, which is determinant for virulence. We investigated the transcriptional changes involved in this cellular remodeling and found an upregulation of transcripts related to ribosome biogenesis at the beginning (6 h) of infection and a later (10 days) upregulation of transcripts involved in the inositol pathway, energy production, and the proteasome. Consistent with a role for the proteasome, we found that its inhibition delayed cell remodeling during infection with the H99 strain. Altogether, these results further our understanding of the infection biology of C. neoformans and provide perspectives to support therapeutic and diagnostic targets for cryptococcosis.

Clinical features, outcomes, and long-term survival times of cats and dogs with central nervous system cryptococcosis in Australia: 50 cases (2000-2020)

OBJECTIVE

To describe the clinical findings and outcomes of Australian cats and dogs with CNS cryptococcosis.

ANIMALS

19 cats and 31 dogs with CNS cryptococcosis diagnosed between 2000 and 2020.

PROCEDURES

A case series and cohort study were performed using the same 50 animals. Both studies were multi-institutional and both retrospective and prospective. Disease features were compared between cats and dogs, and associations between putative risk factors and survival time (ST) were assessed.

RESULTS

Dogs were younger at initial presentation than cats and had lower latex cryptococcal antigen agglutination titers. Extraneurologic signs were common and frequently involved sinonasal and contiguous tissues. Neuroanatomic localization was predominantly forebrain, central vestibular (including cerebellum), multifocal, or diffuse. CSF analysis predominantly showed pleocytosis, with eosinophilic inflammation common in dogs. Seventy-eight percent (39/50) of patients received antifungal treatment. Median STs (from presentation) in treated patients were 1,678 days for cats and 679 days for dogs. Abnormal mentation at presentation (in dogs) and CSF collection (in cats) were associated with shorter STs. In treated dogs, those that received glucocorticoids prior to diagnosis, or single rather than multiple antifungal agents, had shorter STs.

CLINICAL RELEVANCE

The prognosis for feline and canine CNS cryptococcosis is guarded, yet long STs are possible with appropriate treatment. Presence of subtle upper respiratory tract signs may suggest cryptococcosis in patients with neurologic signs, while the absence of neurologic signs does not preclude CNS involvement.

Modification of Hinge/Transmembrane and Signal Transduction Domains Improves the Expression and Signaling Threshold of GXMR-CAR Specific to Cryptococcus spp

Chimeric antigen receptors (CARs) redirect T cells to recognize a specific target. CAR components play a pivotal role in antigen specificity, structure stability, expression on cell surface, and induction of cellular activation, which together determine the success of CAR T-cell therapy. CAR products targeting B-cell lymphoma encouraged the development of new CAR applications beyond cancer. For example, our group developed a CAR to specifically target glucuronoxylomannan (GXM) in the capsule of Cryptococcus species, called GXMR-CAR or GXMR-IgG4-28ζ. Cryptococcus are fungi that cause the life-threatening disease cryptococcosis, and GXMR-IgG4-28ζ redirected T cells to target yeast and titan cell forms of Cryptococcus spp. Here, we replaced the IgG4-hinge and CD28-transmembrane domains from GXMR-CAR with a CD8α molecule as the hinge/transmembrane and used CD28 or 4-1BB molecules as co-stimulatory domains, creating GXMR-8-28ζ and GXMR-8-BBζ, respectively. Jurkat cells expressing GXMR-CAR containing CD8α as the hinge/transmembrane improved the CAR expression and induced a tonic signaling. GXMR-8-28ζ and GXMR-8-BBζ induced high levels of IL-2 and up-regulation of CD69 expression in the presence of reference strains of C. neoformans and C. gattii. Moreover, GXMR-8-28ζ and GXMR-8-BBζ showed increased strength in response to incubation with clinical isolates of Cryptococcuss spp., and 4-1BB co-stimulatory domain triggered a more pronounced cellular activation. Dasatinib, a tyrosine kinase inhibitor, attenuated the GXMR-CAR signaling cascade's engagement in the presence or absence of its ligand. This study optimized novel second-generation GXMR-CARs containing the CD8-hinge/transmembrane domain that improved CAR expression, antigen recognition, and signal strength in T-cell activation.

Emergence of infectious diseases and role of advanced nanomaterials in point-of-care diagnostics: a review

Infectious outbreaks are the foremost global public health concern, challenging the current healthcare system, which claims millions of lives annually. The most crucial way to control an infectious outbreak is by early detection through point-of-care (POC) diagnostics. POC diagnostics are highly advantageous owing to the prompt diagnosis, which is economical, simple and highly efficient with remote access capabilities. In particular, utilization of nanomaterials to architect POC devices has enabled highly integrated and portable (compact) devices with enhanced efficiency. As such, this review will detail the factors influencing the emergence of infectious diseases and methods for fast and accurate detection, thus elucidating the underlying factors of these infections. Furthermore, it comprehensively highlights the importance of different nanomaterials in POCs to detect nucleic acid, whole pathogens, proteins and antibody detection systems. Finally, we summarize findings reported on nanomaterials based on advanced POCs such as lab-on-chip, lab-on-disc-devices, point-of-action and hospital-on-chip. To this end, we discuss the challenges, potential solutions, prospects of integrating internet-of-things, artificial intelligence, 5G communications and data clouding to achieve intelligent POCs.