Cryptococcal meningitis

Defence Warriors: Exploring the crosstalk between polyamines and oxidative stress during microbial pathogenesis

Microbial infections have been a widely studied area of disease research since historical times, yet they are a cause of severe illness and deaths worldwide. Furthermore, infections by pathogens are not just restricted to humans; instead, a diverse range of hosts, including plants, livestock, marine organisms and fish, cause significant economic losses and pose threats to humans through their transmission in the food chain. It is now believed that both the pathogen and the host contribute to the outcomes of a disease pathology. Researchers have unravelled numerous aspects of host-pathogen interactions, offering valuable insights into the physiological, cellular and molecular processes and factors that contribute to the development of infectious diseases. Polyamines are key factors regulating cellular processes and human ageing and health. However, they are often overlooked in the context of host-pathogen interactions despite playing a dynamic role as a defence molecule from the perspective of the host as well as the pathogen. They form a complex network interacting with several molecules within the cell, with reactive oxygen species being a key component. This review presents a thorough overview of the current knowledge of polyamines and their intricate interactions with reactive oxygen species in the infection of multiple pathogens in diverse hosts. Interestingly, the review covers the interplay of the commensals and pathogen infection involving polyamines and reactive oxygen species, highlighting an unexplored area within this field. From a future perspective, the dynamic interplay of polyamines and oxidative stress in microbial pathogenesis is a fascinating area that widens the scope of developing therapeutic strategies to combat deadly infections.

Natural Products in Precision Neurological Disease (Cryptococcal Meningitis): Structure-Based Phytochemical Screening of Glycyrrhiza glabra Plant Against Cryptococcus neoformans Farnesyltransferase (FTase)

Cryptococcus neoformans causes cryptococcal meningitis, which is lethal to immune-compromised people, especially AIDS patients. This study employed diverse in silico techniques to find the best phytochemical to block farnesyltransferase (FTase). Based on molecular docking, the top two compounds selected from a screening of 5807 phytochemical compounds from 29 medicinal plants were CID_8299 (hydroxyacetone) and CID_71346280 (1,7-bis (4-hydroxyphenyl)-1,4,6-heptatrien-3-one), with docking scores of -5.786 and -0.078 kcal/mol, respectively, indicating stronger binding affinities than the control CID_3365 (fluconazole), which scored -4.2 kcal/mol. The control and lead compounds bind at the common active site of protein by interacting with common amino acid residues (HIS97, GLN408, PHE93, and TRP94). Post-docking MM-GBSA verified docking score where CID_8299 and CID_71346280 had negative binding free energies of -19.81 and -0.27 kcal/mol, respectively. These two lead compounds were reassessed through molecular dynamics simulation (100 ns), and several post-dynamics analyses were conducted. CID_71346280, 8299, and 3365 (control) showed average RSMD values of 3.17, 1.904, and 2.08; average root mean square fluctuation values of 1.167, 0.886, and 1.028 Å; average radius of gyration values of 5.13, 1.58, and 3.54 Å; average solvent accessible surface area values of 121.16, 3.51, and 183.81 Å2; average H-bond values of 466.05, 470.84, and 456.84 Å, respectively. The results revealed that CID_8299 had the highest stability and consistent interaction with the target protein throughout the simulation period. According to the toxicity analysis, CID_8299, which is found in the Glycyrrhiza glabra plant, can also cross the BBB, which makes it unbeatable in treating neuro-disease caused by C. neoformans and may potentially block FTase protein's activity inhibiting post-translational lipidation of essential signal transduction protein.

Latex microspheres lateral flow immunoassay with smartphone-based device for rapid detection of Cryptococcus

Cryptococcus is a pathogenic fungus that poses a threat to human health. Conventional detection methods have limited the rapid and accurate qualitative and quantitative analysis of Cryptococcus, affecting early diagnosis and treatment. In this study, we developed a Point-of-Care Testing (POCT) platform that integrates lateral flow immunoassay (LFIA) with smartphones, enabling both rapid qualitative and quantitative detection of Cryptococcus. The LFIA strip utilizes latex microspheres (LMs) as labeling probes, achieving a detection limit of 3000 CFU/mL and presenting higher sensitivity than the Colloidal Gold Nanoparticles Lateral Flow Immunoassay (AuNPs-LFIA) strip, and approximately eight times that of the AuNPs-LFIA strip. Additionally, it exhibiting no cross-reactivity with over 24 common pathogens and validated in clinical samples. For quantitative analysis, artificial intelligence algorithms were employed to convert smartphone-captured images into grayscale values. Eleven feature values were utilized as a dataset for machine learning to construct a linear regression model, with Mean Squared Error (MSE) and R2 reaching 0.45 and 0.91, respectively. Moreover, the recovery rates in the serum samples ranged from 90.0 % to 108 %, indicating a good practicability. This research presents a rapid diagnostic technology for Cryptococcus and lays the theoretical and technical groundwork for detecting other pathogens.

Spectrum of cryptococcal manifestations in a young male with human immunodeficiency virus

We present the case of a young male with human immunodeficiency virus and a history of nonadherence to antiretroviral therapy who developed cryptococcal meningitis. This case highlights the diverse medical and clinical presentations of central nervous system cryptococcosis in an immunocompromised individual from a radiology perspective. CT and MR imaging demonstrated basal ganglia enhancement and leptomeningeal involvement, characteristic of this pathogen. This report underscores the significance of advanced imaging modalities, in particular MRI, in diagnosing cryptococcal meningitis. Additionally, other manifestations of cryptococcus, including within the thorax, are highlighted in the same patient. The combination of these findings, along with confirmatory cerebral spinal fluid analysis, are crucial to the rapid initiation of an appropriate antifungal regimen for treatment.

A rare case of cryptococcal meningitis with infarction of the splenium of the corpus callosum in an immunocompetent patient: A case report

Meningitis is a severe infection of the central nervous system. Cryptococcus neoformans is an uncommon fungal agent that can cause meningitis and often manifests unusual symptoms. While this infection is more prevalent in immunocompromised patients, it can also affect immunocompetent patients. A 33-year-old housewife living in the village visited our hospital emergency department complaining of a severe headache and mild fever for 7 days. We diagnosed an unusual occurrence of cryptococcal meningitis with infarction of the splenium of the corpus callosum in a patient who appeared to have a healthy immune system. This disease should be considered in immunocompetent individuals with persistent headache or other neurological findings, even in the absence of overt risk factors.

Roles of Different Signaling Pathways in Cryptococcus neoformans Virulence

Cryptococcus neoformans is a widespread fungal pathogen that can infect the human central nervous system (CNS) and cause fungal meningitis, leading to hundreds of thousands of deaths worldwide each year. Previous studies have demonstrated that many signal transduction pathways are crucial for the morphological development and virulence of C. neoformans. In this review, data from over 116 research articles have been compiled to show that many signaling pathways control various characteristics of C. neoformans, individually or in association with other pathways, and to establish strong links among them to better understand C. neoformans pathogenesis. Every characteristic of C. neoformans is closely linked to these signaling pathways, making this a rich area for further research. It is essential to thoroughly explore these pathways to address questions that remain and apply a molecular mechanistic approach to link them. Targeting these pathways is crucial for understanding the exact mechanism of infection pathogenesis and will facilitate the development of antifungal drugs as well as the diagnosis and prevention of cryptococcosis.

Polymerase chain reaction negative cryptococcal meningitis

A 61-year-old male with subacute headache was found to have cryptococcal meningitis despite a negative BioFire FilmArray meningitis/encephalitis panel. This case underscores the importance of liberal cryptococcal antigen testing, and that a negative FilmArray panel is inadequate in excluding cryptococcal meningitis, particularly in a HIV-negative host.

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.

Rapid duplex flap probe-based isothermal assay to identify the Cryptococcus neoformans and Cryptococcus gattii

Cryptococcosis is a life-threatening invasive fungal infection with significantly increasing mortality worldwide, which is mainly caused by Cryptococcus neoformans and Cryptococcus gattii. These two species complexes have different epidemiological and clinical characteristics, indicating the importance of accurate differential diagnosis. However, the clinically used culture method and cryptococcal capsular antigen detection couldn't achieve the above goals. Herein, we established a novel duplex flap probe-based isothermal assay to identify the Cryptococcus neoformans and Cryptococcus gattii within 1 hour. This assay combined the highly sensitive nucleic acid isothermal amplification and highly specific fluorescence probe method, which could effectively distinguish the sequence differences of the two species complexes using two different fluorescence flap probes in a single reaction system. This novel method showed excellent detection performance with sensitivity (10 copies/μL each) and specificity (100%) compared to traditional culture and sequencing methods. Furthermore, we applied this method to spiked clinical samples, 30 cerebrospinal fluids and 30 bronchoalveolar lavage fluids, which kept good detection performance. This novel rapid duplex flap probe-based isothermal assay is a promising and robust tool for applications in differential diagnosis of the Cryptococcus neoformans and Cryptococcus gattii in clinical settings, especially when clinical suspicion for cryptococcal disease is high and epidemiological studies.

A comparison of the surgical outcomes of ventriculoperitoneal versus lumbar peritoneal shunts in the management of intracranial hypertension secondary to cryptococcal meningitis in HIV infected adult patients

OBJECTIVE

Cryptococcal meningitis (CM), an AIDS-defining illness, significantly impacts morbidity and mortality. This study aims to compare complications arising from ventriculoperitoneal shunt (VPS) and lumbar peritoneal shunt (LPS) procedures used to manage refractory intracranial hypertension (IH) secondary to CM in HIV-infected patients.

METHODS

Retrospective data were collected from January 2003 to January 2015 for HIV-infected adults diagnosed with refractory IH secondary to CM and subsequently shunted. Demographics, clinical characteristics, antiretroviral therapy, laboratory findings (including CD4 count and CSF results), CT brain scan results, shunt-related complications, and mortality were compared between VPS and LPS groups.

RESULTS

This study included 83 patients, with 60 (72%) undergoing VPS and 23 (28%) receiving LPS. Mean ages were comparable between VPS (32.5) and LPS (32.2) groups (p = 0.89). Median CD4+ counts were 76 cells/µl (IQR= 30-129) in VPS versus 54 cells/µl (IQR= 31-83) in LPS (p=0.45). VPS group showed a higher mean haemoglobin of 11.5 g/dl compared to 9.9 g/dl in the LPS group (p=0.001). CT brain scans showed hydrocephalus in 55 VPS and 13 LPS patients respectively. Shunt complications were observed in 17 (28%) VPS patients versus 10 (43.5%) LPS patients (p=0.5). Patients developing shunt sepsis in the VPS group exhibited a median CD4+ count of 117 cells/µl (IQR= 76-129) versus 48 cells/µl (IQR= 31- 66) in the LPS group (p=0.03). Early shunt malfunction occurred more frequently in the LPS group compared to VPS group (p=0.044). The mean hospital stay was 6.2 days for VPS versus 5.4 days for LPS patients (p=0.9). In-hospital mortality was 6%, occurring in three VPS and two LPS patients respectively.

CONCLUSION

Shunting procedures remain important surgical interventions for refractory IH secondary to HIV-related CM. However, cautious consideration is warranted for patients with CD4 counts below 200 cells/µL due to increased shunt complications. This study suggests a trend toward higher complication rates in patients undergoing LPS insertion.

Chronic cryptococcal meningitis with a cryptococcoma presenting as normal pressure hydrocephalus: a case report

Chronic meningitis may present with clinical features related to hydrocephalus. We report a 76-year-old female who presented to an outpatient clinic with cognitive decline and gait disturbance with recurrent falls. The initial diagnosis of normal pressure hydrocephalus (NPH) was based on the clinical symptoms and magnetic resonance imaging (MRI) of the brain, which showed ventriculomegaly without an obstructive lesion. During follow-up, however, there was remarkable cognitive decline, and she was unable to walk without assistance. Lumbar puncture and brain MRI showed respective lymphocyte-dominant pleocytosis that was positive for cryptococcal antigen and a new encapsulated abscess-like lesion in a left caudate head. Treatment for cryptococcal meningitis was initiated, and the patient was cured after a long treatment with an antifungal agent. As chronic meningitis could be misdiagnosed as NPH, differential diagnoses of etiologies that can cause hydrocephalus should be addressed.

Predictive Performance of Scoring Systems for Mortality Risk in Patients with Cryptococcemia: An Observational Study

Cryptococcal infection is usually diagnosed in immunocompromised individuals and those with meningeal involvement, accounting for most cryptococcosis. Cryptococcemia indicates a poor prognosis and prolongs the course of treatment. We use the scoring systems to predict the mortality risk of cryptococcal fungemia. This was a single hospital-based retrospective study on patients diagnosed with cryptococcal fungemia confirmed by at least one blood culture collected from the emergency department covering January 2012 and December 2020 from electronic medical records in the Taichung Veterans General Hospital. We enrolled 42 patients, including 28 (66.7%) males and 14 (33.3%) females with a mean age of 63.0 ± 19.7 years. The hospital stay ranged from 1 to 170 days (a mean stay of 44.4 days), and the overall mortality rate was 64.3% (27/42). In univariate analysis, the AUC of ROC for MEWS, RAPS, qSOFA, MEWS plus GCS, REMS, NEWS, and MEDS showed 0.833, 0.842, 0.848, 0.846, 0.846, 0.878, and 0.905. In the multivariate Cox regression analysis, all scoring systems, older age, lactate, MAP, and DBP, indicated significant differences between survivor and non-survivor groups. Our results show that all scoring systems could apply in predicting the outcome of patients with cryptococcal fungemia, and the MEDS displays the best performance. We recommend a further large-scale prospective study for patients with cryptococcal fungemia.

Comparative metabolomic profiling of Cupriavidus necator B-4383 revealed production of cupriachelin siderophores, one with activity against Cryptococcus neoformans

Cupriavidus necator H16 is known to be a rich source of linear lipopeptide siderophores when grown under iron-depleted conditions; prior literature termed these compounds cupriachelins. These small molecules bear β-hydroxyaspartate moieties that contribute to a photoreduction of iron when bound as ferric cupriachelin. Here, we present structural assignment of cupriachelins from C. necator B-4383 grown under iron limitation. The characterization of B-4383 cupriachelins is based on MS/MS fragmentation analysis, which was confirmed by 1D- and 2D-NMR for the most abundant analog (1). The cupriachelin congeners distinguish these two strains with differences in the preferred lipid tail; however, our rigorous metabolomic investigation also revealed minor analogs with changes in the peptide core, hinting at a potential mechanism by which these siderophores may reduce biologically unavailable ferric iron (4-6). Antifungal screening of the C. necator B-4383 supernatant extract and the isolated cupriachelin analog (1) revealed inhibitory activity against Cryptococcus neoformans, with IC50 values of 16.6 and 3.2 μg/mL, respectively. This antifungal activity could be explained by the critical role of the iron acquisition pathway in the growth and pathogenesis of the C. neoformans fungal pathogen.

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.

Clinical and pathological characterization of Central Nervous System cryptococcosis in an experimental mouse model of stereotaxic intracerebral infection

Infection of the Central Nervous System (CNS) by the encapsulated fungus Cryptococcus neoformans can lead to high mortality meningitis, most commonly in immunocompromised patients. While the mechanisms by which the fungus crosses the blood-brain barrier to initiate infection in the CNS are well recognized, there are still substantial unanswered questions about the disease progression once the fungus is established in the brain. C. neoformans is characterized by a glucuronoxylomannan (GXM)-rich polysaccharide capsule which has been implicated in immune evasion, but its role during the host CNS infection needs further elucidation. Therefore, the present study aims to examine these key questions about the mechanisms underlying cryptococcal meningitis progression and the impact of fungal GXM release by using an intracerebral rodent infection model via stereotaxic surgery. After developing brain infection, we analyzed distinct brain regions and found that while fungal load and brain weight were comparable one-week post-infection, there were region-specific histopathological (with and without brain parenchyma involvement) and disease manifestations. Moreover, we also observed a region-specific correlation between GXM accumulation and glial cell recruitment. Furthermore, mortality was associated with the presence of subarachnoid hemorrhaging and GXM deposition in the meningeal blood vessels and meninges in all regions infected. Our results show that using the present infection model can facilitate clinical and neuropathological observations during the progression of neurocryptococcosis. Importantly, this mouse model can be used to further investigate disease progression as it develops in humans.

Mouse Organotypic Brain Slice Cultures: A Novel Model for Studying Neuroimmune Responses to Cryptococcal Brain Infections

Cryptococcal meningitis affects millions of people worldwide and is especially prevalent in regions with a high burden of HIV/AIDS. The study of the pathophysiology of this often fatal disease has been significantly hindered by the lack of reliable experimental models, especially at the level of the brain, which is the main organ of injury. Here we outline our novel protocol for the use of hippocampal organotypic brain slice cultures (HOCs) to study the host-fungal interactions during cryptococcal infections of the brain. HOCs are a powerful platform for investigating neuroimmune interactions as they allow for the preservation of all innate neuroglial cells including microglia, astrocytes, and neurons, all of which maintain their three-dimensional architecture and functional connectivity. We made HOCs from neonatal mice and infected these with a fluorescent strain of Cryptococcus neoformans for 24 h. Using immunofluorescent staining, we confirmed the presence and morphology of microglia, astrocytes, and neurons in HOCs prior to infection. Using fluorescent and light microscopy, we also confirmed that Cryptococcus neoformans encapsulates and buds in vitro, as it would in a host. Finally, we demonstrate that infection of HOCs with Cryptococcus neoformans results in close association of the fungal cells with host microglial cells. Our results demonstrate the utility of HOCs as a model to study the pathophysiology and host neuroimmune responses in neurocryptococcosis, which may assist in improving our collective understanding of the pathogenesis of this disease.

A Suspected Case of COVID-19-Induced Immunosuppression

While COVID-19 has gained popularity as a pandemic and as a cause of pulmonary-systemic disease, the condition continues to evolve our knowledge and understanding of immunology and medicine through its myriad clinical presentations. This article features a previously healthy 65-year-old female who presented with sudden features of cryptococcal meningitis, the progression of which raises questions as to what role the virus plays in the innate, adaptive, and overall host factors leading to immunosuppression.

Short-term and long-term outcomes in patients with cryptococcal meningitis after ventriculoperitoneal shunt placement

OBJECTIVE

The purpose of this study was to assess the short-term and long-term outcomes of ventriculoperitoneal shunt (VPS) placement in patients with cryptococcal meningitis (CM).

METHODS

We performed a retrospective analysis of all patients with CM admitted to the Peking Union Medical College Hospital from September 1990 to January 2021. We collected related clinical features to analyze the short- and long-term outcomes of VPS at 1 month and 1 year at least the following therapy, respectively. Overall survival (OS) was compared with all patients and a subgroup of critically ill cases by the Kaplan-Meier method with the log-rank test. Univariable and multivariable analyses were also performed using the Cox proportional hazard model to identify statistically significant prognostic factors.

RESULTS

We enrolled 98 patients, fifteen of whom underwent VPS. Those who received VPS had a lower cerebrospinal fluid (CSF) Cryptococcus burden (1:1 vs. 1:16; p = 0.046), lower opening pressures (173.3 mmH2 O vs. 224 mmH2O; p = 0.009) at lumbar punctures, and a lower incidence of critical cases (6.7 vs. 31.3%; p = 0.049). According to our long-term follow-up, no significant difference was shown in the Barthel Index (BI) between the two groups. Two patients in the VPS group suffered postoperative complications and had to go through another revision surgery. According to survival analysis, overall survival (OS) between the VPS and non-VPS groups was not significantly different. However, the Kaplan-Meier plots showed that critical patients with VPS had better survival in OS (p < 0.009). Multivariable analyses for critical patients showed VPS was an independent prognostic factor.

CONCLUSION

A VPS could reduce the intracranial pressure (ICP), decrease the counts of Cryptococcus neoformans by a faster rate and reduce the number of critical cases. The VPS used in critical patients with CM has a significant impact on survival, but it showed no improvement in the long-term Barthel Index (BI) vs. the conservative treatment and could lead to postoperative complications.

The effect on brain volume in HIV-negative and non-transplant cryptococcal meningitis

To explore the brain volume (BV) changes of HIV-negative and non-transplant cryptococcal meningitis (CM) in one year after initial therapy. Case data were collected from 78 CM patients who underwent magnetic resonance imaging (MRI) scanning at least 3 times in one-year interval after initial therapy. The assessment of BV was measured by a non-commercial software, uAI Research Portal. Linear mixed model was used to investigate the association between clinical characteristics and the changes of BV. Longitudinal study showed a decrease in total brain volume (-4.65 cm3, p = 0.005), regional brain volume including white matter (-2.86 cm3, p = 0.031) and basal ganglia (-0.25 cm3, p = 0.007), and an increase in cerebrospinal fluid (CSF) volume (3.58 cm3, p = 0.013) in CM patients in one year after initial therapy. Ventricular volume in patients with ventriculoperitoneal shunts (VPS) was lower than that in patients without VPS (-7.5 cm3, p < 0.05). Ventricular volume in patients with post-infectious inflammatory response syndrome (PIIRS) was larger than that in patients without PIIRS (7.1 cm3, p < 0.01). In addition, temporal lobe atrophy was associated with corticosteroid therapy (-6.8 cm3, p < 0.01). The present study suggested that brain atrophy, especially regional BV decrease, could happen in the HIV-negative and non-transplant CM patients over a one-year interval.

Basic Analysis of the Cerebrospinal Fluid: An Important Framework for Laboratory Diagnostics of the Impairment of the Central Nervous System

Laboratory analysis of basic cerebrospinal fluid (CSF) parameters is considered as essential for any CSF evaluation. It can provide rapidly very valuable information about the status of the central nervous system (CNS). Our retrospective study evaluated parameters of basic CSF analysis in cases of either infectious or non-infectious CNS involvement. Neutrophils are effector cells of innate immunity. Predominance of neutrophils was found in 98.2% of patients with purulent inflammation in CNS. Lymphocytes are cellular substrate of adaptive immunity. We found their predominance in 94.8% of patients with multiple sclerosis (MS), 66.7% of patients with tick-borne encephalitis (TBE), 92.2% of patients with neuroborreliosis, 83.3% of patients with inflammatory response with oxidative burst of macrophages in CNS and 75.0% of patients with malignant infiltration of meninges (MIM). The simultaneous assessment of aerobic and anaerobic metabolism in CSF using the coefficient of energy balance (KEB) allows us to specify the type of inflammation in CNS. We found predominantly aerobic metabolism (KEB > 28.0) in 100.0% CSF of patients with normal CSF findings and in 92.8% CSF of patients with MS. Predominant faintly anaerobic metabolism (28.0 > KEB > 20.0) in CSF was found in 71.8% patients with TBE and in 64.7% patients with neuroborreliosis. Strong anaerobic metabolism (KEB < 10.0) was found in the CSF of 99.1% patients with purulent inflammation, 100.0% patients with inflammatory response with oxidative burst of macrophages and in 80.6% patients with MIM. Joint evaluation of basic CSF parameters provides sufficient information about the immune response in the CSF compartment for rapid and reliable diagnosis of CNS involvement.

Cryptococcus Infection in an Immunocompetent Patient

Cryptococcal meningitis is a fungal infection of the CNS, generally thought of as an opportunistic infection in those with T-cell immunodeficiencies including AIDS (usually with a CD4 count of less than 100), chronic steroid use, hematological malignancies, and transplant recipients.

It can have irreversible CNS morbidity, including vision loss, intracranial hypertension, and cognitive decline. Diagnosis depends on cerebrospinal fluid (CSF) analysis, in which cultures and cryptococcal antigen are most sensitive. CSF PCR can also be done. Most patients have disseminated disease, and blood cultures are also positive. Outcomes remain guarded, with a poor prognosis (morbidity and high mortality) among survivors. This article presents a case of cryptococcal meningitis in an immunocompetent individual, where absolutely no identifiable risk factor was present.

Central Nervous System Cryptococcosis in Patients With Sarcoidosis: Comparison With Non-sarcoidosis Patients and Review of Potential Pathophysiological Mechanisms

Introduction

Cryptococcus spp. infection of the central nervous system (CINS) is a devastating opportunistic infection that was historically described in patients with acquired immunodeficiency syndrome (AIDS). Cryptococcus spp. infections are also associated with sarcoidosis; the impairment of cell-mediated immunity and long-term corticosteroid therapy being evoked to explain this association. Nevertheless, this assertion is debated and the underlying pathophysiological mechanisms are still unknown. The aims of this study were (i) to describe the clinical and biological presentation, treatments, and outcomes of CINS patients with and without sarcoidosis and (ii) to review the pathophysiological evidence underlying this clinical association.

Patients and Methods

Every patient with positive cerebrospinal fluid (CSF) cryptococcal antigen testing, India ink preparation, and/or culture from January 2015 to December 2020 at a tertiary university hospital were included, and patients with sarcoidosis were compared with non-sarcoidosis patients. Quantitative variables are presented as mean ± SD and are compared using the Mann-Whitney Wilcoxon rank-sum test. Categorical variables are expressed as the number of patients (percentage) and compared using the χ² or Fisher's tests.

Results

During the study period, 16 patients experienced CINS, of whom 5 (31%) were associated with sarcoidosis. CINS symptoms, biological, and CSF features were similar between CINS patients with and without sarcoidosis except regarding CD4 cells percentages and CD4/CD8 ratio that was higher in those with sarcoidosis (47 ± 12 vs. 22 ± 18, p = 0.02 and 2.24 ± 1.42 vs. 0.83 ± 1.10, p = 0.03, respectively). CINS patients with sarcoidosis had less often positive blood antigen testing than those without sarcoidosis (2/5 vs. 11/11, p = 0.02). CINS patients with and without sarcoidosis were treated with similar drugs, but patients with sarcoidosis had a shorter length of treatment. CD4 cell levels do not seem to explain the association between sarcoidosis and cryptococcosis.

Conclusion

Sarcoidosis was the most frequently associated condition with CINS in this study. CINS patients associated with sarcoidosis had overall similar clinical and biological presentation than CINS patients associated with other conditions but exhibited a lower rate of positive blood cryptococcal antigen testing and higher CD4/CD8 T cells ratio. Pathophysiological mechanisms underlying this association remain poorly understood but B-1 cell deficiency or lack of IgM could be a part of the explanation. Another plausible mechanism is the presence of anti-granulocyte-macrophage colony-stimulating factor (GM-CSF) antibodies in a subset of patients with sarcoidosis, which could impair macrophage phagocytic function. Further studies are strongly needed to better understand those mechanisms and to identify at-risk patients.

Cryptococcus gattii meningitis complicated by immune reconstitution inflammatory syndrome in an apparent immunocompetent host in Malaysia

Cryptococcosis is a systemic fungal infection caused by Cryptococcus neoformans or Cryptococcus gattii. Cryptococcus causes a wide range of diseases, ranging from asymptomatic pulmonary lesions to disseminated disease involving the central nervous system, particularly meningoencephalitis. C. gattii infection has rarely been reported in Malaysia. We present a case of C. gattii meningitis with pulmonary cryptococcosis complicated by immune reconstitution inflammatory syndrome in an apparently immunocompetent person with no prior travel history.

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Cryptococcosis is a fungal infection causing significant morbidity and mortality.

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Cryptococcus gattii can present with meningitis and pulmonary cryptococcosis.

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CSF examination is the cornerstone of diagnosis in cryptococcal meningitis.

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IRIS is a rare complication of C. gattii infection that can be treated with steroids.

Clinical Profile of 24 AIDS Patients with Cryptococcal Meningitis in the HAART Era: A Report from an Infectious Diseases Tertiary Hospital in Western Romania

Management of cryptococcal infections among patients suffering from acquired immunodeficiency syndrome (AIDS) represents a medical challenge. This retrospective study aims to describe the disease management and outcomes among 24 AIDS patients who suffered from Cryptococcus neoformans meningitis. The parameters evaluated from our patients’ database records include epidemiological data, clinical manifestations, biochemical and microbiological analysis of patients’ cerebrospinal fluid (CSF), treatment profiles, and disease outcomes. All patients included in the study had a lymphocyte count of less than 200 CD4/mm³. Of the 24 patients included in this study, five had been diagnosed with HIV infection since childhood, after receiving HIV-infected blood transfusions. The most prominent symptom was fatigue in 62.5% of patients, followed by nausea/vomiting and headache. Seven patients had liver cirrhosis due to hepatitis B virus (HBV) or hepatitis C virus (HCV) infection, while Kaposi sarcoma and cerebral toxoplasmosis were found in two patients. Six out of 24 patients died due to bacterial sepsis and acute respiratory distress syndrome (ARDS). High intracranial pressure was the strongest predictive factor for mortality (OR = 2.9), followed by ARDS (OR = 1.8), seizures at disease onset (OR = 1.4), and diabetes mellitus (OR = 1.2). Interestingly, patients younger than 40 years old had a significantly lower survival rate than that of the older patients. Before developing Cryptococcal meningitis, all patients had low adherence to the early ART treatment scheme and skipped the follow-up visits. All patients received a combination of amphotericin B and flucytosine as induction therapy, adding fluconazole for maintenance. Simultaneously, AIDS HAART was initiated at diagnosis of the cryptococcal infection. A combined regimen of antifungals and highly active antiretroviral therapy showed improved patient recovery with minor side effects.

Discovery and Characterization of a Rapidly Fungicidal and Minimally Toxic Peptoid against Cryptococcus neoformans

A limited number of antifungals are available to treat infections caused by fungal pathogens such as Cryptococcus neoformans and Candida albicans. Current clinical antifungals are generally toxic, and increasing resistance to these therapies is being observed, necessitating new, effective, and safe antifungals. Peptoids, or N-substituted glycines, have shown promise as antimicrobial agents against bacteria, fungi, and parasites. Herein we report the discovery and characterization of an antifungal peptoid termed RMG8-8. This compound was originally discovered from a combinatorial peptoid library using the Peptoid Library Agar Diffusion assay to screen against C. albicans. Though the efficacy of RMG8-8 against C. albicans was modest (25 μg/mL), the efficacy against C. neoformans was excellent (1.56 μg/mL). Cytotoxicity against a panel of cell lines proved RMG8-8 to be minimally toxic, with selectivity ratios ranging from 34 to 121. Additional studies were carried out to determine the pharmacological importance of each peptoid monomer in RMG8-8, characterize the killing kinetics of this compound against C. neoformans (t _1/2 = 6.5 min), and evaluate plasma protein binding and proteolytic stability. Finally, a liposomal lysis assay suggested that RMG8-8 likely exerts fungal killing through membrane permeabilization, the generally accepted mechanism of action for most antimicrobial peptides and peptoids.

Cryptococcosis and unexpected death

Cryptococcosis is a fungal disease caused predominantly by Cryptococcus neoformans and Cryptococcus gatti. It is most often found in immunocompromised individuals and has quite protean and chronic manifestations affecting all body systems. The unexpected death of a 22-year-old man with cryptococcal meningoencephalitis demonstrates, however, that it may have a fulminant course in previously well individuals. Also present at autopsy was a toruloma of the upper lobe of the right lung. Delays in clinical diagnoses, confusion with tuberculosis and precipitate clinical deterioration may mean that cases will be encountered unexpectedly during medicolegal autopsies.

The role of optic nerve sheath diameter ultrasound in brain infection

Brain infections cause significant morbidity and mortality worldwide, especially in resource-limited settings with high HIV co-infection rates. Raised intracranial pressure [ICP] may complicate brain infection and worsen neurological injury, yet invasive ICP monitoring is often unavailable. Optic nerve sheath diameter [ONSD] ultrasound may allow detection of raised ICP at the bedside; however, pathology in brain infection is different to traumatic brain injury, in which most studies have been performed. The use of ONSD ultrasound has been described in tuberculous meningitis, cryptococcal meningitis and cerebral malaria; however correlation with invasive ICP measurement has not been performed. Normal optic nerve sheath values are not yet established for most populations, and thresholds for clinical intervention cannot be assumed to match those used in non-infective brain pathology. ONSD ultrasound may be suitable for use in resource-limited settings by clinicians with limited ultrasound training. Standardisation of scanning technique, consensus on normal ONSD values, and action on abnormal results, are areas for future research. This scoping review examines the role of ONSD ultrasound in brain infection. We discuss pathophysiology, and describe the rationale, practicalities, and challenges of utilising ONSD ultrasound for brain infection monitoring and management. We discuss the existing evidence base for this technique, and identify knowledge gaps and future research priorities.

Infectious ophthalmoplegias

Though infections account for a significant proportion of patients with ocular motor palsies, there is surprising paucity of literature on infectious ophthalmoplegias. Almost all types of infectious agents (bacteria, viruses, fungi and parasites) can lead to ocular motor palsies. The causative infectious agent can be diagnosed in most cases using an orderly stepwise approach. In this review we discuss how to approach a patient with ophthalmoplegia with main focus on infectious etiologies.

Cryptococcal Virulence in Humans: Learning From Translational Studies With Clinical Isolates

Cryptococcosis, an invasive mycosis caused by Cryptococcus spp, kills between 20% and 70% of the patients who develop it. There are no vaccines for prevention, and treatment is based on a limited number of antifungals. Studying fungal virulence and how the host responds to infection could lead to new therapies, improving outcomes for patients. The biggest challenge, however, is that experimental cryptococcosis models do not completely recapitulate human disease, while human experiments are limited due to ethical reasons. To overcome this challenge, one of the approaches used by researchers and clinicians is to: 1) collect cryptococcal clinical isolates and associated patient data; 2) study the set of isolates in the laboratory (virulence and host-pathogen interaction variables, molecular markers); 3) correlate the laboratory and patient data to understand the roles fungal attributes play in the human disease. Here we review studies that have shed light on the cryptococcosis pathophysiology using these approaches, with a special focus on human disease. Isolates that more effectively evade macrophage responses, that secrete more laccase, melanize faster and have larger capsules in the cerebrospinal fluid are associated with poorer patient outcomes. Additionally, molecular studies have also shown that cryptococcal clades vary in virulence, with clinical impact. Limitations of those studies include the use of a small number of isolates or retrospectively collected clinical data. The fact that they resulted in very important information is a reflection of the impact this strategy has in understanding cryptococcosis and calls for international collaboration that could boost our knowledge.

The interplay of phenotype and genotype in Cryptococcus neoformans disease

Cryptococcus neoformans is an opportunistic fungal pathogen that causes life-threatening meningitis primarily in immunocompromised individuals. In order to survive and proliferate during infection, C. neoformans must adapt to a variety of stresses it encounters within the host. Patient outcome depends on the interaction between the pathogen and the host. Understanding the mechanisms that C. neoformans uses to facilitate adaptation to the host and promote pathogenesis is necessary to better predict disease severity and establish proper treatment. Several virulence phenotypes have been characterized in C. neoformans, but the field still lacks a complete understanding of how genotype and phenotype contribute to clinical outcome. Furthermore, while it is known that C. neoformans genotype impacts patient outcome, the mechanisms remain unknown. This lack of understanding may be due to the genetic heterogeneity of C. neoformans and the extensive phenotypic variation observed between and within isolates during infection. In this review, we summarize the current understanding of how the various genotypes and phenotypes observed in C. neoformans correlate with human disease progression in the context of patient outcome and recurrence. We also postulate the mechanisms underlying the genetic and phenotypic changes that occur in vivo to promote rapid adaptation in the host.

Cryptococcus neoformans-Infected Macrophages Release Proinflammatory Extracellular Vesicles: Insight into Their Components by Multi-omics

Cryptococcus neoformans causes cryptococcal meningitis, which is frequent in patients with HIV/AIDS, especially in less-developed countries. The incidence of cryptococcal meningitis is close to 1 million each year globally.

Cryptococcus neoformans causes deadly mycosis in immunocompromised individuals. Macrophages are key cells fighting against microbes. Extracellular vesicles (EVs) are cell-to-cell communication mediators. The roles of EVs from infected host cells in the interaction with Cryptococcus remain uninvestigated. Here, EVs from viable C. neoformans-infected macrophages reduced fungal burdens but led to shorter survival of infected mice. In vitro, EVs induced naive macrophages to an inflammatory phenotype. Transcriptome analysis showed that EVs from viable C. neoformans-infected macrophages activated immune-related pathways, including p53 in naive human and murine macrophages. Conserved analysis demonstrated that basic cell biological processes, including cell cycle and division, were activated by infection-derived EVs from both murine and human infected macrophages. Combined proteomics, lipidomics, and metabolomics of EVs from infected macrophages showed regulation of pathways such as extracellular matrix (ECM) receptors and phosphatidylcholine. This form of intermacrophage communication could serve to prepare cells at more distant sites of infection to resist C. neoformans infection.

Evaluation of the Dynamiker Cryptococcal Antigen Lateral Flow Assay for the Diagnosis of HIV-Associated Cryptococcosis

Cryptococcal meningitis is a leading cause of meningitis in sub-Saharan Africa. Given the need for rapid point-of-care testing, we evaluated the diagnostic performance of the Dynamiker cryptococcal antigen (CrAg) lateral flow assay (LFA). We assessed the diagnostic performance of the Dynamiker CrAg LFA compared to the IMMY CrAg LFA as the reference standard. We tested 150 serum, 115 plasma, and 100 cerebrospinal fluid (CSF) samples from HIV patients with symptomatic meningitis and 113 serum samples from patients with suspected asymptomatic cryptococcal antigenemia. Compared to the IMMY CrAg LFA, sensitivity of Dynamiker CrAg LFA was 98% in serum, 100% in plasma, 100% in CSF from symptomatic patients and 96% in serum from asymptomatic patients. Specificity was 66% in serum, 61% in plasma, and 91% in CSF from symptomatic patients, and 86% in serum from asymptomatic patients. The positive predictive value was 85% in serum, 82% in plasma, and 96% in CSF from symptomatic patients, and 69% in serum from asymptomatic patients. The negative predictive value was 94% in serum, 100% in plasma, and 100% in CSF from symptomatic patients, and 99% in serum from asymptomatic patients. The interassay reproducibility was 100% across the four sample types with no observed discordant results when Dynamiker CrAg LFA was tested in duplicate. However, a high number of false positives were observed on serum of symptomatic patients (11%), serum of asymptomatic patients (11%) and plasma of symptomatic patients (14%). The Dynamiker CrAg LFA had excellent sensitivity but poor specificity, particularly when tested on serum and plasma.

Clinical features and para-clinical findings of cryptococcal meningitis in the North of Iran during 2011-19

Background and Purpose:

Cryptococcal meningitis (CM) is a serious fungal infection that especially affects patients with human immunodeficiency virus (HIV). In this regard, the present retrospective study aimed to analyze the clinical and laboratory features and therapeutic outcomes of patients with CM admitted to two teaching referral centers in the north of Iran during 2011-19.

Materials and Methods:

This study was performed on all the hospitalized patients diagnosed with CM in two therapeutic centers of infectious diseases in the north of Iran. The required data, such as demographic characteristics and clinical and paraclinical features of patients, were extracted and entered in the information forms. Finally, the collected data were analyzed in SPSS software (version 16).

Results:

For the purpose of the study, records of 12 confirmed CM patients were evaluated in this research. Based on the results, 75% of the patients were male. Moreover, the average age of the subjects was 40.33± 8.93 years old and 66.6% of them (n=8) were HIV-positive. Other underlying diseases among HIV-positive patients included infection with hepatitis C virus (25%) and a history of tuberculosis (25%). In total, three HIV-negative patients suffered from Hodgkin lymphoma (25%), sarcoidosis (25%), and asthma (25%) and one patient (25%) had no underlying disease. Headache (75%), weakness, and fatigue (75%) were the most common symptoms among the participants. The cluster of differentiation 4 (CD4) count in all HIV-positive patients was less than 100 cells/μl. There was no significant difference between symptoms in HIV-positive and HIV-negative patients. Besides, no significant difference was observed between the groups of HIV-positive and HIV-negative patients regarding the period between the onset of symptoms and diagnosis of CM, the length of hospital stay, and the duration of antifungal medication consumption. In total, three patients (25%) expired, and six patients recovered. The CM recurred in two HIV-negative and one HIV-positive subjects; the two HIV-negative patients were treated, while the HIV-positive patient expired due to this recurrence.

Conclusion:

Clinical features and cerebrospinal fluid parameters were not different in HIV-positive and HIV-negative participants. Despite the fact that CM is not common in Iran, due to the increasing number of immunosuppressive patients, the differential diagnosis of CM should be considered for patients with signs and symptoms of infection in the central nervous system.

Clinical insights and epidemiology of central nervous system infection due to Cryptococcus neoformans/gattii species complexes: A prospective study from South India

In the last two decades, central nervous system (CNS) cryptococcosis (CNSc) has emerged as a major opportunistic infection in the immunocompromised population of India. We have analyzed the clinical features of CNSc and epidemiology of Cryptococcus neoformans and Cryptococcus gattii. A total of 160 clinical isolates of C. neoformans/gattii recovered from CNSc patients were analyzed. The origin, clinical parameters, and imaging features of the patients were recorded, and clinical parameters were analyzed based on their human immunodeficiency virus (HIV) status and infecting species, namely, C. neoformans or C. gattii. Serotypes and mating types of the isolates were determined. Molecular typing was performed by polymerase chain reaction (PCR) fingerprinting using M13 microsatellite primer (GTG)5, and multilocus sequence typing (MLST). Majority of the patients were from Bangalore Urban, Karnataka. Among 160 cases 128 (80%) were HIV seropositive, and 32 (20%) were HIV negative. Middle-aged males (36-55 years) were highly affected. There were statistically significant differences in the clinical manifestations, imaging and CSF parameters of HIV coinfected and noninfected cases, whereas limited differences were observed in these parameters in the cases infected with C. neoformans and C. gattii. We identified 80% C. neoformans VNI, 8.75% VNII and 22.5% C. gattii (VGI), 8.75% C. tetragattii (VGIV) among clinical strains. This comprehensive study will contribute toward a better prognosis of CNS cryptococcosis patients during the hospital stay, treatment strategies for HIV coinfected and noninfected cases and will provide the molecular epidemiology of these two pathogenic fungal species in south India, which was unclear in this part of the country.

Targeting Unconventional Pathways in Pursuit of Novel Antifungals

The impact of invasive fungal infections on human health is a serious, but largely overlooked, public health issue. Commonly affecting the immunocompromised community, fungal infections are predominantly caused by species of Candida, Cryptococcus, and Aspergillus. Treatments are reliant on the aggressive use of pre-existing antifungal drug classes that target the fungal cell wall and membrane. Despite their frequent use, these drugs are subject to unfavorable drug-drug interactions, can cause undesirable side-effects and have compromised efficacy due to the emergence of antifungal resistance. Hence, there is a clear need to develop novel classes of antifungal drugs. A promising approach involves exploiting the metabolic needs of fungi by targeted interruption of essential metabolic pathways. This review highlights potential antifungal targets including enolase, a component of the enolase-plasminogen complex, and enzymes from the mannitol biosynthesis and purine nucleotide biosynthesis pathways. There has been increased interest in the enzymes that comprise these particular pathways and further investigation into their merits as antifungal targets and roles in fungal survival and virulence are warranted. Disruption of these vital processes by targeting unconventional pathways with small molecules or antibodies may serve as a promising approach to discovering novel classes of antifungals.

High Prevalence of Cryptococcus neoformans and Isolation of Other Opportunistic Fungi From Pigeon (Columba livia) Droppings in Northeast Iran

Cryptococcus neoformans is an opportunistic human pathogen that causes cryptococcosis, a life-threatening infection that usually manifests as meningoencephalitis in immunocompromised patients. Pigeon (Columba livia) droppings can spread pathogenic yeasts and mold fungi, such as C neoformans, in the environment. The objective of this study was to isolate C neoformans and other opportunistic fungi from feral pigeon droppings. One hundred twenty samples of feral pigeon droppings were suspended 1:10 in saline solution and then cultured. The fungi were identified by standard mycological techniques. Fungal contamination was detected in all examined samples. Yeast and mold fungi were isolated from 114 samples (95%) and 103 samples (85.8%), respectively, out of 120 samples. The highest frequency of yeast and mold fungi isolated from collected samples was C neoformans 77.5% and Rhizopus species 38.3%, respectively. Several types of fungi exist in pigeon droppings that can be spread in the environment and transmitted to children and elderly, as well as immunocompromised patients who are at increased risk of contracting opportunistic diseases.

Current burden of serious fungal infections in Republic of Congo

BACKGROUND

The Republic of Congo (RoC) is characterised by a high prevalence of tuberculosis and HIV/AIDS, which largely drive the epidemiology of serious fungal infections.

OBJECTIVE

We aimed to estimate the current burden of serious fungal infections in RoC.

MATERIAL AND METHODS

Using local, regional or global data and estimates of population and at-risk population groups, deterministic modelling was employed to estimate national incidence or prevalence of the most serious fungal infections.

RESULTS

Our study revealed that about 5.4% of the Congolese population (283 450) suffer from serious fungal infections yearly. The incidence of cryptococcal meningitis, Pneumocystis jirovecii pneumonia and disseminated histoplasmosis in AIDS patients was estimated at 560, 830 and 120 cases per year. Oral and oesophageal candidiasis collectively affects 12 320 HIV-infected patients. Chronic pulmonary aspergillosis, 67% post-tuberculosis, probably has a prevalence of 3420. Fungal asthma (allergic bronchopulmonary aspergillosis and severe asthma with fungal sensitisation) probably has a prevalence of 3640 and 4800, although some overlap due to disease definition is likely. The estimated prevalence of recurrent vulvovaginal candidiasis and tinea capitis is 85 440 and 178 400 respectively. Mostly related to agricultural activity, fungal keratitis affects an estimated 700 Congolese yearly.

CONCLUSION

These data underline the urgent need for an intensified awareness towards Congolese physicians to fungal infections and for increased efforts to improve diagnosis and management of fungal infections in the RoC.

Cerebrospinal fluid pleocytosis in immunocompromised patients: Can it be Cryptococcus

Cryptococcal meningitis commonly affects immunocompromised cases and can have varied presentation. In some instances, the presence of a plethora of inflammatory cells on cerebrospinal fluid (CSF) in an immunosuppressed patient can lead to further investigations, which unravel the presence of cryptococcal meningitis. The aim of this retrospective study was to analyze the spectrum of CSF findings of immunosuppressed patients who were diagnosed to have cryptococcal meningitis. Retrospective analysis of CSF cytospin slides exhibiting pleocytosis and belonging to immunocompromised patients was performed, and these cases were found to have cryptococcal meningitis. Out of 932 cases of CSF (January 2016-July 2017), 10 had pleocytosis and 5 of these 10 cases demonstrated spores of Cryptococcus. Male-to-female ratio was 1:1.5. All the patients were immunocompromised and had CSF leukocytosis. Lymphocytes and monocytes were present in all samples while only one case showed plasma cells. Spores of Cryptococcus were also noted in all the cases and highlighted on India Ink Preparation and Gomori Methenamine Silver stain. All the cases were positive for agglutination-based cryptococcal antigen assay, except one where the test was not done. All immunosuppressed patients having pleocytosis in CSF were found to have cryptococcal infection. Therefore, pleocytosis in CSF in any immunosuppressed patient should raise the suspicion of cryptococcal meningitis. The pathologist and the clinician need to be vigilant in such scenarios to rule out any opportunistic infection and investigate the patient thoroughly for any underlying immunosuppression.

Caenorhabditis elegans as a model animal for investigating fungal pathogenesis

The morbidity and mortality associated with systemic fungal infections in humans cannot be underestimated. The nematode Caenorhabditis elegans has become popular for the in vivo study of the pathogenesis of human fungal pathogens and as an antifungal drug-screening tool. C. elegans offers many advantages as a model organism for the study of human fungal diseases, including lack of ethics requirements, easy maintenance in the laboratory, fully sequenced genome, availability of genetic mutants, and the possibility of liquid assays for high-throughput antifungal screening. Its major drawbacks include the inability to grow at 37 °C and absence of an adaptive immune response. However, several virulence factors involved in the pathogenesis of medically important fungal pathogens have been identified using the C. elegans model, consequently providing new leads for drug discovery and potential drug targets. We review the use of C. elegans as a model animal to understand the pathogenesis of medically important human fungal pathogens and the discovery of novel antifungal compounds. The review makes a case for C. elegans as a suitable invertebrate model for a plethora of practical applications in the investigation of fungal pathogenesis as well as its amenability for liquid-based high-throughput screening of potential antifungal compounds.

Fungal diseases at the medical front door

Fungal diseases are an increasingly recognized cause of mortality worldwide and often pose diagnostic challenges. This article focuses on common fungal diseases as they may present in the acute medical unit, looking at the initial investigation and management of four common diseases: Pneumocystis jirovecii pneumonia, cryptococcal meningitis, candidaemia and allergic bronchopulmonary aspergillosis. There is an increase in morbidity and mortality if these conditions are not correctly diagnosed and thus appropriate therapy is delayed. A better understanding of the initial investigation and management of these conditions will improve the outcome of patients with fungal diseases presenting to the 'medical front door'.

Cryptococcal Meningoencephalitis Presenting as a Psychiatric Emergency

BACKGROUND

Organic conditions can often mimic neuropsychiatric disorders, leading to delays in diagnosis and treatment for the most vulnerable populations presenting to the emergency department (ED).

CASE REPORT

Here we discuss a case of cryptococcal meningoencephalitis seemingly consistent with psychosis on initial evaluation, and present strategies to recognize and treat this condition. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: Due to the indolent time course of this disease, initial symptoms of altered mental status and personality changes may be attributed to drug use or psychiatric illness before more overt evidence for increased intracranial pressure and neurologic infection develops. It is important for emergency clinicians to maintain a high level of suspicion for this condition in at-risk patients and reassess them frequently during their ED visit.

Cryptococcal Meningitis and Anti-virulence Therapeutic Strategies

Fungal infections of the central nervous system are responsible for significant morbidity and mortality. Cryptococcus neoformans (Cn) is the primary cause of fungal meningitis. Infection begins in the lung after inhalation of fungal spores but often spreads to other organs, particularly the brain in immunosuppressed individuals. Cn’s ability to survive phagocytosis and endure the onslaught of oxidative attack imposed by the innate immune response facilitates dissemination to the central nervous system (CNS). Despite the success of Cn at bypassing innate immunity, entry into the heavily protected brain requires that Cn overwhelm the highly restricted blood-brain barrier (BBB). This is a formidable task but mounting evidence suggests that Cn expresses surface-bound and secreted virulence factors including urease, metalloprotease, and hyaluronic acid that can undermine the BBB. In addition, Cn can exploit multiple routes of entry to gain access to the CNS. In this review, we discuss the cellular and molecular interface of Cn and the BBB, and we propose that the virulence factors mediating BBB crossing could be targeted for the development of anti-virulence drugs aimed at preventing fungal colonization of the CNS.