Evolution of Cryptococcal Antigen Testing: What is new?

Cryptococcosis

Cryptococcosis is an invasive fungal infection caused by yeasts of the genus Cryptococcus that causes a significant global burden of disease in both immunocompromised and immunocompetent individuals. Over the past several decades, diagnosis and management of cryptococcal disease have moved to focus on rapid, reliable, and cost-effective care delivery, with the advent of new antigen detection assays and novel antifungal treatment strategies.

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.

Disseminated Cryptococcus infection presenting as lytic skeletal lesions suggesting bony metastatic disease

A 76-year-old male diagnosed with sarcoidosis presented with atraumatic left anterior knee pain. Initial imaging of the left lower extremity revealed an eccentrically-based lytic lesion in the mid-distal femur with cortical erosion and an additional lytic lesion in the proximal tibia. Magnetic resonance imaging (MRI) demonstrated an aggressive lesion in the proximal tibia with surrounding marrow edema, cortical breach, and erosion into the distal patellar tendon. Given concern for metastatic bone lesions, a18-fluorodeoxyglucose positron emission tomography/computed tomography scan (FDG PET/CT) was performed which demonstrated concordant hypermetabolic lytic lesions at the left mid-distal femur and the left proximal tibia, as well as hypermetabolic diffuse lymphadenopathy. The patient was presumed to have metastatic lung cancer based on the presence of lung nodules. Due to concern for impending pathologic fracture, the patient underwent open biopsy with a plan for prophylactic fixation of both lesions. Intra-operatively, however, both lesions were found to contain pus, from which cultures ultimately grew Cryptococcus neoformans. This is a case of disseminated skeletal cryptococcosis masquerading as metastatic cancer in a patient without classic risk factors for disseminated cryptococcosis (defined as extrapulmonary evidence of infection). Classically, disseminated cryptococcosis is thought to occur in severely immunocompromised patients, such as those with human immunodeficiency virus (HIV) or organ transplant recipients. This case highlights the need to maintain a high index of suspicion in patients with underlying immunocompromising conditions, including less common conditions such as sarcoid, who present with bony lesions. This case report then discusses the diagnostic evaluation and treatment of disseminated skeletal cryptococcosis.

The Impact of the Fungal Priority Pathogens List on Medical Mycology: A Northern European Perspective

Fungal diseases represent a considerable global health concern, affecting >1 billion people annually. In response to this growing challenge, the World Health Organization introduced the pivotal fungal priority pathogens list (FPPL) in late 2022. The FPPL highlights the challenges in estimating the global burden of fungal diseases and antifungal resistance (AFR), as well as limited surveillance capabilities and lack of routine AFR testing. Furthermore, training programs should incorporate sufficient information on fungal diseases, necessitating global advocacy to educate health care professionals and scientists. Established international guidelines and the FPPL are vital in strengthening local guidance on tackling fungal diseases. Future iterations of the FPPL have the potential to refine the list further, addressing its limitations and advancing our collective ability to combat fungal diseases effectively. Napp Pharmaceuticals Limited (Mundipharma UK) organized a workshop with key experts from Northern Europe to discuss the impact of the FPPL on regional clinical practice.

The SSS revolution in fungal diagnostics: speed, simplicity and sensitivity

INTRODUCTION

Fungal disease has historically presented a diagnostic challenge due to its often non-specific clinical presentations, relative infrequency and reliance on insensitive and time-intensive fungal culture.

SOURCES OF DATA

We present the recent developments in fungal diagnostics in the fields of serological and molecular diagnosis for the most clinically relevant pathogens; developments that have the potential to revolutionize fungal diagnosis through improvements in speed, simplicity and sensitivity. We have drawn on a body of evidence including recent studies and reviews demonstrating the effectiveness of antigen and antibody detection and polymerase chain reaction (PCR) in patients with and without concurrent human immunodeficiency virus infection.

AREAS OF AGREEMENT

This includes recently developed fungal lateral flow assays, which have a low cost and operator skill requirement that give them great applicability to low-resource settings. Antigen detection for Cryptococcus, Histoplasma and Aspergillus spp. are much more sensitive than culture. PCR for Candida spp., Aspergillus spp., Mucorales and Pneumocystis jirovecii is more sensitive than culture and usually faster.

AREAS OF CONTROVERSY

Effort must be made to utilize recent developments in fungal diagnostics in clinical settings outside of specialist centres and integrate their use into standard medical practice. Given the clinical similarities of the conditions and frequent co-infection, further study is required into the use of serological and molecular fungal tests, particularly in patients being treated for tuberculosis.

GROWING POINTS

Further study is needed to clarify the utility of these tests in low-resource settings confounded by a high prevalence of tuberculosis.

AREAS TIMELY FOR DEVELOPING RESEARCH

The diagnostic utility of these tests may require revision of laboratory work flows, care pathways and clinical and lab coordination, especially for any facility caring for the immunosuppressed, critically ill or those with chronic chest conditions, in whom fungal disease is common and underappreciated.

Lack of education, knowledge, and supplies are barriers to cryptococcal meningitis care among nurses and other healthcare providers in rural Uganda: A mixed methods study

BACKGROUND

Cryptococcal meningitis (CM) is one of the deadliest opportunistic infections related to HIV/AIDS. A research gap exists surrounding the barriers to CM diagnosis, treatment delivery, and care from the healthcare provider's perspective.

OBJECTIVES

The purpose of this study was to elucidate provider's behaviors, to identify barriers and facilitators to diagnose and treat CM, and to assess their knowledge of CM, cryptococcal screening, and treatment.

DESIGN, SETTING, AND PARTICIPANTS

A convergent mixed-methods study among twenty healthcare providers who provided CM patient referrals to Lira Regional Referral Hospital in Lira, Uganda.

METHODS

Surveys and interviews were conducted to obtain information from healthcare providers who referred CM patients to Lira Regional Referral Hospital from 2017 to 2019. Questions related to provider education, knowledge, barriers to CM care, and patient education were inquired to understand the providers' perspectives.

RESULTS

Nurses had the least amount of CM knowledge with half knowing the cause of CM. Approximately half the participants knew about CM transmission, but only 15 % knew the duration of CM maintenance therapy. Most participants (74 %) last had education regarding CM during didactic training. In addition, 25 % disclosed they never educate patients due to time constraints (30 %) and lack of knowledge (30 %). Nurses (75 %) were least likely to provide patient education. Most participants acknowledged their lack of CM knowledge and attributed it to a lack of education and perceived inexperience with CM.

CONCLUSIONS

Providers' gaps in knowledge due to the lack of education and experience contributes to decreased patient education, and the lack of access to appropriate supplies affects their provision for CM diagnosis, treatment, and care. These results can guide evidence-based interventions to improve health providers' knowledge. Recommendations for standardized CM education should be developed for both providers and patients in collaboration with professional boards and the Uganda Ministry of Health.

Infections after organ transplantation and immune response

Organ transplantation has provided another chance of survival for end-stage organ failure patients. Yet, transplant rejection is still a main challenging factor. Immunosuppressive drugs have been used to avoid rejection and suppress the immune response against allografts. Thus, immunosuppressants increase the risk of infection in immunocompromised organ transplant recipients. The infection risk reflects the relationship between the nature and severity of immunosuppression and infectious diseases. Furthermore, immunosuppressants show an immunological impact on the genetics of innate and adaptive immune responses. This effect usually reactivates the post-transplant infection in the donor and recipient tissues since T-cell activation has a substantial role in allograft rejection. Meanwhile, different infections have been found to activate the T-cells into CD₄⁺ helper T-cell subset and CD₈⁺ cytotoxic T-lymphocyte that affect the infection and the allograft. Therefore, the best management and preventive strategies of immunosuppression, antimicrobial prophylaxis, and intensive medical care are required for successful organ transplantation. This review addresses the activation of immune responses against different infections in immunocompromised individuals after organ transplantation.

New Organic-Inorganic Salt Based on Fluconazole Drug: TD-DFT Benchmark and Computational Insights into Halogen Substitution

In this study, we report the synthesis of a new organic–inorganic molecular salt of the clinically used antifungal drug fluconazole, (H2Fluconazole).SnCl₆.2H₂O. By detailed investigation and analysis of its structural properties, we show that the structure represents a 0D structure built of alternating organic and inorganic zig-zag layers along the crystallographic c-axis and the primary supramolecular synthons in this salt are hydrogen bonding, F···π and halogen bonding interactions. Magnetic measurements reveal the co-existence of weak ferromagnetic behavior at low magnetic field and large diamagnetic contributions, indicating that the synthesized material behaves mainly as a diamagnetic material, with very low magnetic susceptibility and with a band gap energy of 3.6 eV, and the salt is suitable for semiconducting applications. Extensive theoretical study is performed to explain the acceptor donor reactivity of this compound and to predict the Cl-substitution effect by F, Br and I. The energy gap, frontier molecular orbitals (FMOs) and the different chemical reactivity descriptors were evaluated at a high theoretical level. Calculations show that Cl substitution by Br and I generates compounds with more important antioxidant ability and the intramolecular charge transfer linked to the inorganic anion.

Comparison of laboratory diagnosis, clinical manifestation, and management of pulmonary cryptococcosis: Report of the clinical scenario and literature review

BACKGROUND

Pulmonary cryptococcosis is an opportunistic aggressive mycosis in immunocompromised patients, but it can be increasingly seen in immunocompetent patients. It is still challenging to make a rapid and accurate diagnosis due to the various clinical manifestations and limitations in the diagnostic tools.

METHOD

A 54-year-old man presented with intermittent productive cough and fever for 1 week. A chest X-ray demonstrated multiple consolidations in both lungs. Blood biochemistry indicated elevated immunoglobulin G levels. Including sputum cultures, polymerase chain reaction (PCR) tests for severe acute respiratory syndrome coronavirus 2, influenza A and B virus were all negative. Computed tomography of the chest showed ground-glass opacities with a nodular pattern. The serum cryptococcal antigen test was positive; however, the cerebral spinal fluid was negative. The diagnosis of pulmonary cryptococcal infection was made. An initial bronchoscopy was performed unsuccessfully and the patient received intravenous fluconazole therapy for 2 weeks. Due to poor improvement of clinical condition, he then underwent a surgical lung biopsy. The pathology revealed several encapsulated yeast cells, diffuse pulmonary interstitial fibrosis, noncaseating granulomas surrounded by T lymphocytes and multinucleated giant cells with intracellular inclusions, confirming pulmonary yeast infection associated with hypersensitivity pneumonitis. Ultimately, fungal cultures of the pathology samples revealed Cryptococcus neoformans. Subsequently antifungal therapy combined with oral steroid treatment, his general condition improved. After a total of 6 months of antifungal therapy, the patient recovered completely.

CONCLUSIONS

Applicable laboratory diagnosis can help facilitate the accurate and rapid diagnosis of pulmonary cryptococcosis. This report elected to provide an update on the topic of laboratory diagnosis, clinical manifestation, and management of pulmonary cryptococcosis.

Infectious Meningitis and Encephalitis

Infectious meningitis and encephalitis are associated with significant morbidity and mortality worldwide. Acute bacterial meningitis is rapidly fatal and early recognition and institution of therapy are imperative. Viral meningitis is typically a benign self-limited illness. Chronic meningitis (defined as presenting with >4 weeks of symptoms) is most often caused by tuberculosis and fungal infection. Because the diagnostic testing for tuberculous meningitis is insensitive and cultures often take weeks to grow, therapy is often initiated empirically when the diagnosis is suspected. Human simplex virus encephalitis is the most common cause of encephalitis and requires prompt treatment with intravenous acyclovir.

Comparison of a Lateral Flow Assay and a Latex Agglutination Test for the Diagnosis of Cryptococcus Neoformans Infection

Infections by the basidiomycete yeast Cryptococcus neoformans are life-threatening diseases claiming more than 600,000 lives every year. The most common manifestation is cryptococcal meningitis in AIDS patients. Diagnosis primarily relies on antigen testing from serum and cerebrospinal fluid (CSF). Current guidelines recommend rapid antigen testing with a focus on point-of-care assays. Over the recent years, a range of new lateral flow assays (LFAs) was launched. There is still a lack of data evaluating the CE-certified Biosynex RDT CryptoPS LFA. We compared the performance of this LFA with a latex agglutination assay (LAA; Latex-Cryptococcus Antigen Detection System, IMMY) from blood and CSF samples. Blood and/or CSF samples of 27 patients with proven cryptococcal infections caused by different species and blood-CSF pairs of 20 controls were tested applying LFA and LAA. Upon combined analysis of blood and CSF, both assays were able to identify all C. neoformans infections. Based on CSF analysis only, the LFA and the LAA had sensitivities of 100% and 93%. Neither test gave false-positive results nor was reactive in two cases of C. non-neoformans/non-gattii species infections. Both assays have high sensitivities and specificities for the diagnosis of C. neoformans infection. Contrarily to the IMMY LAA, the RDT CryptoPS LFA is suitable as a point-of-care test but is limited in the quantification of antigen reactivity.

Application and evaluation of nucleic acid sequence-based amplification, PCR and cryptococcal antigen test for diagnosis of cryptococcosis

Background

Cryptococcosis is a major opportunistic invasive mycosis in immunocompromised patients, but it is also increasingly seen in immunocompetent patients. In the early stages of cryptococcosis, limitations of the detection method may hinder the diagnosis. A molecular diagnostic technique based on nucleic acid sequence-based amplification (NASBA) method was developed to fulfil the need for efficient diagnosis of cryptococcosis.

Methods

We compared the diagnostic performance of NASBA, PCR and cryptococcal antigen (CrAg) test (colloidal gold method) in clinical samples from 25 cryptococcosis patients (including 8 cryptococcal meningoencephalitis and 17 pulmonary cryptococcosis) who were categorized as proven cases (n = 10) and probable cases (n = 15) according to the revised EORTC/MSG definitions. 10 patients with non-Cryptococcus infection and 30 healthy individuals were categorized as control group.

Results

The lowest detection limit of NASBA was 10 CFU/mL, and RNA of non-target bacteria or fungi was not amplified. The sensitivity of NASBA, PCR and colloidal gold method was 92.00% (95% CI 72.50–98.60%), 64.00% (95% CI 42.62–81.29%), 100.00% (95% CI 83.42–100.00%), and the specificity was 95.00% (95% CI 81.79–99.13%), 80.00% (95% CI 63.86–90.39%) and 82.50% (95% CI 66.64–92.11%) respectively. The highest specificity (97.50%), accuracy (95.38%) and k value (0.90) were achieved when both NASBA and colloidal gold results were positive.

Conclusions

NASBA is a new alternative detection method for cryptococcosis which is both accurate and rapid without expensive equipment and specialised personnel. It may be used as a tool for confirming current infection as well as monitoring the effectiveness of antifungal treatment. The use of NASBA to detect Cryptococcus RNA in blood samples is of great significance for the diagnosis of pulmonary cryptococcosis. The combination of NASBA and colloidal gold can improve the diagnostic accuracy of cryptococcosis.

Cost-effectiveness analysis and budgetary impact of the Cryptococcal Antigen Lateral Flow Assay (CRAG-LFA) implementation for the screening and diagnosis of cryptococcosis in asymptomatic people living with HIV in Brazil

Cryptococcal infection is a frequent cause of mortality in Brazilian HIV-infected patients. The present study aimed to evaluate the cost-effectiveness and budgetary impact of four cryptococcosis screening strategies in HIV-infected patients with CD4+ ≤ 200 cells/mm³, in Brazil. A Monte Carlo microsimulation was used to compare the following diagnostic tests: a systematic serum cryptococcal antigen (CRAG) screening with latex agglutination (CRAG-LA), a lateral flow immunochromatographic test (CRAG-LFA), India ink staining and no intervention. The rationale was that of the Unified Health System (SUS), and the time horizon was of one year for the intervention and of five years for the budgetary impact analysis (BIA). The effectiveness outcomes were years of life and years of life adjusted for quality (QALY). The cost-effectiveness analysis showed that the two cryptococcal antigen tests were cost-effective, presenting with superior results in comparison with India ink and no screening. CRAG-LFA, compared to CRAG-LA, has an incremental cost of US$0.25 and an incremental cost-effectiveness ratio of US$73.36 (considering the US dollar equal to 5 reais, the Brazilian current money). The probabilistic sensitivity analysis between CRAG-LFA and CRAG-LA, despite showing a high agreement between the two tests, indicated the superiority of CRAG-LFA. The BIA estimated that the incorporation of CRAG-LFA would have an additional cost of approximately U$S 10.4 million dollars in five years. These findings suggest that, for the group of studied patients, the adoption of CRAG-LFA and CRAG-LA are cost-effective, while the India ink test and no intervention are less effective strategies. The BIA showed that using the CRAG-LFA test for people living with HIV (PLHIV) with CD4+ ≤ 200 cells/mm³ could reduce costs for the Brazilian Unified Health System (SUS).

Associations between Cryptococcus Genotypes, Phenotypes, and Clinical Parameters of Human Disease: A Review

The genus Cryptococcus contains two primary species complexes that are significant opportunistic human fungal pathogens: C. neoformans and C. gattii. In humans, cryptococcosis can manifest in many ways, but most often results in either pulmonary or central nervous system disease. Patients with cryptococcosis can display a variety of symptoms on a spectrum of severity because of the interaction between yeast and host. The bulk of our knowledge regarding Cryptococcus and the mechanisms of disease stem from in vitro experiments and in vivo animal models that make a fair attempt, but do not recapitulate the conditions inside the human host. To better understand the dynamics of initiation and progression in cryptococcal disease, it is important to study the genetic and phenotypic differences in the context of human infection to identify the human and fungal risk factors that contribute to pathogenesis and poor clinical outcomes. In this review, we summarize the current understanding of the different clinical presentations and health outcomes that are associated with pathogenicity and virulence of cryptococcal strains with respect to specific genotypes and phenotypes.

Enlarged periventricular space and periventricular lesion extension on baseline brain MRI predicts poor neurological outcomes in cryptococcus meningoencephalitis

In Cryptococcus neoformans meningoencephalitis, brain MRI findings might reflect the phathomechanism of disease progression that is fungal accumulation in the peri-venular space and consequent invasion into the parenchyma. This study analyzed serial brain MRI findings of 76 patients with cryptococcus meningoencephalitis in association with the disease progression and outcomes. MRI parameters included the enlarged periventricular space (ePVS) score (range 0-8), periventricular lesion extension, cryptococcoma, and hydrocephalus. Clinical outcomes at 2-week, 10-week, and 6-month were evaluated using modified Rankin scale (mRS). At 6 months, 15 (19.7%) patients died and 34 (44.1%) had poor neurological outcomes (mRS scores > 2). At baseline, an ePVS score of ≥ 5 (Odds-ratio [OR]: 94.173, 95% confidence-interval [95%CI]: 7.507-1181.295, P < .001), periventricular lesion extension (OR: 51.965, 95%CI: 2.592-1041.673, P = .010), and presence of encephalitis feature (OR: 44.487, 95%CI: 1.689-1172.082, P = .023) were associated with 6-month poor outcomes. Presence of two or more risk factors among encephalitis feature, ePVS score ≥ 5, and periventricular lesion extension at baseline, was associated with 6-month poor outcomes (area under the curve [AUC]: 0.978, P < .001) and mortality (AUC: 0.836, P < .001). Disease progression was associated with interval development of cryptococcoma and hydrocephalus. Brain MRI findings might be useful in predicting outcomes and monitoring the progression of cryptococcus meningoencephalitis.

Disseminated cryptococcosis in a deceased with HIV-1 diagnosed by minimally invasive tissue sampling technique

Minimal invasive tissue sampling (MITS) technique detected HIV infection and disseminated cryptococcosis in an adult female with sudden death. A proper autopsy is essential to diagnose the exact cause of death and MITS can suffice in natural deaths.

Insight into the Assembling Mechanism of Cryptococcus Capsular Glucuronoxylomannan Based on Molecular Dynamics Simulations

Cryptococcus spp. is an invasive fungal pathogen and causes life-threatening cryptococcosis. Opportunistic cryptococcal infections among the immunocompromised population are mostly caused by Cryptococcus neoformans, whereas the geographical dissemination of Cryptococcus gattii in recent years has threatened lives of even immunocompetent people. The capsule, mainly composed of glucuronoxylomannan (GXM) polysaccharides, plays important roles in the virulence of Cryptococcus spp. The assembling mechanism of GXM polysaccharides into the capsule is little understood because of insufficient experimental data. Molecular modeling and molecular dynamics simulation provide insight into the assembling process. We first built GXM oligosaccharide models of serotypes D, A, B, and C and extracted their secondary structure information from simulation trajectories. All the four mainchains tend to take the nearly twofold helical conformation, whereas peripheral sidechains prefer to form left-handed helices, which are further stabilized by intramolecular hydrogen bonds. Based on the obtained secondary structure information, GXM polysaccharide arrays were built to simulate capsule-assembling processes of C. neoformans and C. gattii using serotypes A and C as representatives, respectively. Trajectory analysis illustrates that electrostatic neutralization of acidic sidechain residues of GXM is a prerequisite for capsule assembling, followed by formation of intermolecular hydrogen bond networks. Further insight into the assembling mechanism of GXM polysaccharides provides the possibility to develop novel treatment and prevention solutions for cryptococcosis.

Spatio-temporal Distribution of Meningitis in HIV Patients in Northern Egypt (2000-2018)

BACKGROUND

Meningitis is a leading cause of death among patients living with HIV. There is no adequate tracking of the disease occurrence, distribution and etiologic agents among this risk group in Egypt, although the pattern could differ from that of the general population.

OBJECTIVES

We aimed to describe the spatio-temporal distribution of meningitis in HIV patients in a region of Northern Egypt over 18 years (2000-2018).

METHODS

We conducted a retrospective study of 352 adult HIV patients admitted to a tertiary care fever hospital with neurological manifestations suggesting meningitis. We retrieved from inpatient records all data relevant to patient demographics, clinical presentation, diagnostic work-up, results of laboratory investigations (CSF, blood, imaging), definitive diagnosis, and in-hospital mortality.

RESULTS

The overall trend of over 2 decades showed fluctuating incidence of meningitis in HIV infected patients and increasing spread into rural areas, with a uniform circulation among adult males. Cryptococcal meningitis was the most common etiologic agent (26.9%) and was associated with worse outcomes. Focal neurological deficit (38.5%), cranial nerve involvement (48.1%) were common features in TB Meningitis. The mortality was high (56.8%) and was significantly associated with low CD4+ count, advanced AIDs clinical stage and the presence of co-morbidities.

CONCLUSION

Despite the availability of cART, meningitis, particularly cryptococcal, is common in HIV/AIDS population in Egypt. Continued efforts are desperately needed to improve the outcomes of HIV-infected patients.

Performance of the Lateral Flow Assay and the Latex Agglutination Serum Cryptococcal Antigen Test in Cryptococcal Disease in Patients with and without HIV

Cryptococcal epidemiology is shifting toward HIV-negative populations who have diverse presentations. Cryptococcal antigen (CrAg) testing is also changing, with development of the lateral flow assay (LFA) having reported increased sensitivity and specificity, but with minimal knowledge in the HIV-negative population. In this study, we evaluate the real-life performance of CrAg testing in patients with cryptococcal disease. We conducted a retrospective review of patients with cryptococcosis from 2002 to 2019 at Barnes-Jewish Hospital. Latex agglutination (LA) was used exclusively until April 2016, at which point LFA was used exclusively. Demographics, presentations, and testing outcomes were evaluated. Serum CrAg testing was completed in 227 patients with cryptococcosis. Of 141 HIV-negative patients, 107 had LA testing and 34 had LFA testing. In patients with disseminated disease, serum CrAg sensitivity by LA was 78.1% compared to 82.6% for LFA. In patients with localized pulmonary disease, serum CrAg sensitivity was 23.5% compared to 90.9% for LFA. Of 86 people living with HIV (PLWH), 76 had LA testing, and 10 had LFA testing. Serum CrAg sensitivity for LA was 94.7% compared to 100% for LFA in patients with disseminated disease. We noted a significant improvement in sensitivity from LA testing to LFA testing, predominantly in those with localized pulmonary disease. However, both LFA and LA appear to be less sensitive in HIV-negative patients than previously described in PLWH.

False negative diagnostic errors with polymerase chain reaction for the detection of cryptococcal meningoencephalitis

The accuracy of the BioFire FilmArray Meningitis/Encephalitis (ME) panel for the identification of Cryptococcus has recently been called into question. The primary objective of this study was to assess the agreement between the BioFire ME polymerase chain reaction (PCR) and other markers of cryptococcal infection. This retrospective review identified five patients with cryptococcal meningoencephalitis, 4 of whom had a negative ME panel for Cryptococcus. All five cases had positive serum cryptococcal antigens, and three of five had a positive cerebrospinal fluid (CSF) culture for Cryptococcus. The BioFire ME panel does not appear to be reliable for ruling out Cryptococcus meningoencephalitis; multiple testing methods are recommended.

Broad-band luminescence involving fluconazole antifungal drug in a lead-free bismuth iodide perovskite: Combined experimental and computational insights

The synthesis and characterization of a lead-free perovskite-type material, (C₁₃H₁₄N₆F₂O)₂ Bi₂I₁₀ is reported. It exhibits a zero-dimensional (0D) Bi₂I₁₀^4- octahedral unit, surrounded by a flexible tripodal antifungal ligand (H₂Fluconazole)²⁺. The several intermolecular interactions of the independent cation and the bismuth iodide octahedra were tested via the Hirshfeld surface analysis. The detailed interpretation of the vibrational modes was carried out. The band gap (Eg) of 2.10 eV agrees with the theoretical values. Upon photoexcitation, the crystals exhibit a broadband green emission peaked at 534 nm, which originates from electronic transitions within the inorganic cluster [Bi₂I₁₀]^4-. The theoretical calculations were carried out using DFT and TD-DFT methods to appraise the molecular geometry, vibrational spectra, electronic absorption spectra, frontier molecular orbitals (FOMs) and global reactivity descriptors. Calculations reveal that the energy gap (Eg) and other chemical reactivity descriptors are primarily linked to the inorganic anion and the triazolium rings (A and B) of the organic cation reflecting their importance in the activity and the antioxidant ability of the molecule.

Cell wall polysaccharides from pathogenic fungi for diagnosis of fungal infectious disease

Invasive fungal diseases are associated with significant morbidity and mortality, particularly in immunocompromised individuals. Early and accurate diagnosis is crucial for effective treatment. Despite traditional methods such as microbiological culture, histopathology, radiology and direct microscopy are available, antigen/antibody-based diagnostics are emerging for diagnosis of invasive fungal infections (IFI). Fungal cell wall is a unique structure composed of polysaccharides that are well correlated with fungal burden during fungal infections. Based on this feature, cell wall polysaccharides have been explored as antigens in IFIs diagnostics such as the galactomannan assay, mannan test, β-glucan assay and cryptococcal CrAg test. Herein, we provide an overview on the cell wall polysaccharides from three opportunistic pathogens: Aspergillus fumigatus, Candida albicans and Cryptococcus neoformans, and their applications for IFIs diagnosis. The clinical outcome of newly developed cell wall polysaccharides-based diagnostics is also discussed.

Very early-onset of Cryptococcus neoformans disease following liver transplantation: Report of two cases and a review of the literature

Cryptococcosis is the third most common invasive fungal infection following solid organ transplantation, and mortality is high. Most cases occur late and are due to reactivation of latent infection; however, very early reactivation and donor-derived transmission can occur. Routine screening pre-transplant and antifungal prophylaxis for cryptococcosis post-transplant in solid organ transplantation are not standard practice. We present two cases of very early-onset Cryptococcus neoformans disease following liver transplantation to highlight the need to consider individualized pre-transplant screening and be aware that reactivation of Cryptococcosis neoformans can occur in the immediate post-transplant period.

Clinical Aspects of Immune Damage in Cryptococcosis

Purpose of review

To perform an extensive review of recent literature and provide an update on the current epidemiology, clinical features and management of cryptococcal disease with a focus on the differences between patients depending on their immune status.

Recent findings

Emerging literature has highlighted the inflammatory pathophysiology and varied manifestations of cryptococcal infections in patients who are apparently healthy but paradoxically have a more critical clinical course compared to their immunosuppressed counterparts.

Summary

Non-HIV cryptococcal meningitis has greater mortality compared to that seen in HIV patients. Basic science experiments closely analyzing the underlying pathophysiological response to this infection have demonstrated the predominant role of T cell-mediated inflammatory injury in causing worse clinical outcomes. Further studies are needed to define the need for immunosuppressive agents in the treatment of this illness.

Sensitivity of Cerebrospinal Fluid Cytology for the Diagnosis of Cryptococcal Infections: A 21-Year Single-Institution Retrospective Review

Objectives

Cryptococcal meningoencephalitis is the most common fungal infection of the central nervous system diagnosed by cerebrospinal fluid cytology (CSF) studies. Existing literature suggests that routine CSF cytomorphologic evaluations are exquisitely specific; however, less is known about their sensitivity.

Methods

An electronic record review of the cytopathology and microbiology files was conducted for the 21-year interval from January 1, 1995, through December 31, 2015.

Results

In 21 years, 12,584 CSF samples were processed in the laboratory. Of these, 24 (0.2%) were reported positive for cryptococcal organisms by light microscopy, and 129 CSF fungal cultures were positive for Cryptococcus species. All cotested specimens with positive cytology results were positive on culture (15 specimens, 100% specificity). Twenty-four samples with positive culture results were negative by CSF cytology (sensitivity 39%).

Conclusions

When culture is used as a gold standard, CSF cytology is 100% specific and 39% sensitive, with a positive predictive value of 100% and a negative predictive value of 99.8%.

Fluconazolium oxalate: synthesis and structural characterization of a highly soluble crystalline form

Fluconazole (FLZ) is one of the most used antifungal drugs worldwide and has been the focus of various investigations with the aim of enhancing its biomedical application.

Extent of Lung Involvement and Serum Cryptococcal Antigen Test in Non-Human Immunodeficiency Virus Adult Patients with Pulmonary Cryptococcosis

Background:

Serum cryptococcal antigen (CrAg) test is the most used noninvasive method to detect cryptococcal infection. However, false-negative CrAg test is not uncommon in clinical practice. Then, the aim of this study was to investigate the factors associated with false-negative CrAg test among non-human immunodeficiency virus (HIV) adult patients with pulmonary cryptococcosis and its clinical features.

Methods:

One hundred and fourteen non-HIV adult patients with pulmonary cryptococcosis, proven by biopsy, were retrospectively reviewed. Finally, 85 patients were enrolled; 56 were CrAg positive (CrAg+ group) and 29 were negative (CrAg− group). It was a cross-sectional study. Then, baseline characteristics, underlying diseases, clinical symptoms, laboratory findings, and chest radiological findings were reviewed and analyzed. Chi-square test was used to analyze categorical variable. Odds ratio (OR) was used to measure correlation. Student's t-test was obtained to analyze continuous variable.

Results:

No difference in baseline characteristics, underlying diseases, clinical symptoms, and laboratory findings were found between two groups (P > 0.05 in all). Nevertheless, diffuse extent lesion was 82.1% in CrAg+ group and 10.3% in CrAg− group (χ²= 40.34, P < 0.001; OR = 39.87).

Conclusions:

Among patients with limited pulmonary involvement, a negative serum CrAg does not preclude the diagnosis of pulmonary cryptococcosis. However, among patients with extensive pulmonary involvement, serum CrAg is a useful diagnostic tool for pulmonary cryptococcosis. Furthermore, we also noticed that the untypical and mild presentations with extensive pulmonary lesion might be the features of pulmonary cryptococcosis, which needs further investigation.

[Microbiological diagnosis of invasive mycosis]

The prognosis of invasive fungal infections (IFI) depends on the speed of diagnosis and treatment. Conventional diagnostic methods are of low sensitivity, laborious and too slow, leading to the need for new, faster, and more efficient diagnostic strategies. There are several techniques for diagnosing a candidemia that are faster than the conventional blood culture (BC). Once yeast growth in BC is detected, species identification can be speeded up by mass spectrometry (30minutes), commercialised molecular techniques (60-80minutes) or fluorescent in situ hybridization (90minutes). The combined detection of biomarkers (antimicellium, mannan and anti-mannan or β-glucan) has shown to be of greater use than their individual use. Commercialised nucleic acid amplification techniques (Septifast®, T2Candida®) are very reliable alternatives to BC. The detection of the capsular antigen of Cryptococcus, by means of latex agglutination or immuno-chromatography, is a valuable technique for cryptococcosis diagnosis. Direct microscopic examination and culture of representative specimens is used for the conventional diagnosis of IFI by filamentous fungi. Detection of galactomannan and β-glucan are considered diagnostic criteria for probable invasive aspergillosis and probable IFI, respectively, despite the lack of specificity of the latter. The detection of fungal volatile organic compounds in breath is an interesting diagnostic strategy in pulmonary infections. Although widely used, nucleic acid detection techniques are not considered diagnostic criteria for IFIs caused by moulds in consensus documents, due to their lack of standardisation. However, they are the only alternative to culture methods in invasive infections by Scedosporium/Lomentospora, Fusarium, zygomycetes, or dematiaceous fungi.

Cryptococcal meningitis in a previously healthy child

An 8-year-old previously healthy female presented with a 3 weeks history of headache, neck stiffness, deafness, fever and vomiting and was diagnosed with cryptococcal meningitis. She had documented hearing loss and was referred to tertiary-level care after treatment with fluconazole did not improve her neurological signs and symptoms. Her symptoms slowly resolved over two months. This case report illustrates the occurrence of cryptococcal meningitis in a non-immunocompromised patient, as well as the challenges of providing effective care in resource-limited settings.

Pitfalls Associated With the Use of Molecular Diagnostic Panels in the Diagnosis of Cryptococcal Meningitis

We report the case of a kidney transplantation patient on chronic immunosuppressive therapy presenting with subacute meningitis. The final diagnosis of cryptococcal meningitis was delayed due to 2 false-negative cryptococcal results on a molecular diagnostic panel. Caution with such platforms in suspected cryptococcal meningitis is needed.

Opportunistic Invasive Mycoses in AIDS: Cryptococcosis, Histoplasmosis, Coccidiodomycosis, and Talaromycosis

PURPOSE OF REVIEW

The goal of this review is to provide an update on the epidemiology, diagnosis, and treatment of opportunistic fungal infections in patients with human immunodeficiency virus (HIV) infection including Cryptococcus spp., Histoplasma spp., Coccidioides spp., and Talaromyces marneffei, formerly Penicillium marneffei.

RECENT FINDINGS

In many settings, despite increasing roll out of antiretroviral therapy (ART), opportunistic invasive mycoses produce a substantial burden of disease. The prevalence of specific fungal pathogens depends on their endemicity. Viral suppression achieved by greater access to ART and increased the availability of point-of-care testing with rapid diagnostic tests (RDTs) aid to curtail the associated fungi morbidity. RDTs allow earlier screening to preemptively initiate treatment of opportunistic fungal pathogens. Identifying asymptomatic cryptococcal infection before starting ART is crucial in reducing the risk of the immune reconstitution inflammatory syndrome (IRIS). There is an urgent need to decrease the burden of opportunistic invasive fungal infections in individuals with HIV/AIDS through different interventions: (a) continue to expand the deployment of ART to the most affected populations to achieve viral suppression; (b) ensure early diagnosis of fungal pathogen with point-of-care testing;

Looking for fungi in all the right places: screening for cryptococcal disease and other AIDS-related mycoses among patients with advanced HIV disease

PURPOSE OF REVIEW

As HIV treatment programmes scale up to meet the UNAIDS 90-90-90 goals, care must be taken to start antiretroviral treatment safely in patients with advanced disease (CD4 counts <200 cells/μl) who are simultaneously at risk for opportunistic infections and immune reconstitution inflammatory syndrome. Invasive fungal diseases pose a great threat at this critical time point, though the development of inexpensive and highly accurate rapid diagnostic tests has changed the approach HIV programmes are taking to reduce the high mortality associated with these opportunistic infections. This article summarizes recent advances and findings in fungal opportunistic infection diagnostics with a focus on screening to prevent cryptococcal meningitis.

RECENT FINDINGS

Cryptococcal antigen (CrAg) screening using a lateral flow assay platform is cost-effective and feasible to implement as either a laboratory reflex or point-of-care test. Recent CrAg screening pilots have elucidated the varying prevalence of cryptococcal antigenemia across geographic regions, which may aid programme planning. Evidence from recently completed clinical trials provides a strong motivation for the use of CrAg titer to refine treatment options for patients with subclinical cryptococcal disease.

SUMMARY

Although several operational barriers to programme effectiveness still need to be addressed, the utility of CrAg screening using inexpensive and accurate antigen assays has been demonstrated in real-world HIV programmes, paving the way for development and testing of other fungal opportunistic infection screening strategies and for an integrated advanced HIV disease testing package to reduce AIDS mortality and ensure safe antiretroviral treatment initiation.

Cryptococcal antigen negative meningoencephalitis in HIV/AIDS

Diagnosis of central nervous system cryptococcosis relies on a spectrum of methods but has improved with lateral flow diagnostic assays that detect capsular polysaccharide antigens of Cryptococcus. Here, we present the case of an HIV-infected African-American man with cryptococcal meningoencephalitis caused by a strain producing little or no capsule.

Importance of Resolving Fungal Nomenclature: the Case of Multiple Pathogenic Species in the Cryptococcus Genus

Cryptococcosis is a major fungal disease caused by members of the Cryptococcus gattii and Cryptococcus neoformans species complexes. After more than 15 years of molecular genetic and phenotypic studies and much debate, a proposal for a taxonomic revision was made. The two varieties within C. neoformans were raised to species level, and the same was done for five genotypes within C. gattii. In a recent perspective (K. J. Kwon-Chung et al., mSphere 2:e00357-16, 2017, https://doi.org/10.1128/mSphere.00357-16), it was argued that this taxonomic proposal was premature and without consensus in the community. Although the authors of the perspective recognized the existence of genetic diversity, they preferred the use of the informal nomenclature "C. neoformans species complex" and "C. gattii species complex." Here we highlight the advantage of recognizing these seven species, as ignoring these species will impede deciphering further biologically and clinically relevant differences between them, which may in turn delay future clinical advances.

Cryptococcosis today: It is not all about HIV infection

Purpose of the review

Cryptococcal disease is most often thought of in the context of HIV infection. Much of our knowledge of the disease originates from its management in the HIV-positive population over the last 30 years. While the majority of cases globally continue to occur in the setting of advanced HIV, Cryptococcus species is increasingly responsible for disease in HIV-negative populations including those considered normal hosts and these HIV-negative populations will be the focus of this review.

Recent findings

Currently available data indicated that significant differences exist in epidemiology, clinical presentation, management and outcomes of cryptococcal disease in HIV-negative populations when compared to those living with HIV.

Summary

Further research is required to improve our knowledge of cryptococcal disease in particular in HIV-negative cohorts so as to optimise management of the disease in the future.