Cryptococcal meningitis: a review of cryptococcal antigen screening programs in Africa

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

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

UV-Vis spectrophotometry for rapid and specific quantification of amphotericin B: analytical method validation for ex vivo and in vivo studies in the development of nanoemulsion-incorporated thermosensitive gel

Amphotericin B (AmB) is the first-line drug used for the treatment of cryptococcal meningitis (CM). AmB has poor gastrointestinal permeability due to its large molecular weight. In addition, AmB in injectable form has the disadvantages of high systemic side effects and low bioavailability in the brain because it cannot cross the blood-brain barrier (BBB). Therefore, it is important to develop new drugs with a more optimized delivery system. The nose-to-brain drug delivery system offers many advantages such as high bioavailability in the brain as it does not need to cross the BBB. AmB was developed in nanoemulsion (NE) system which provides controlled release and to avoid nasal clearance system, it was combined with thermosensitive gel (TG). To support the formulation development process, analytical method validation was conducted for AmB in methanol (MeOH) solvent, release media, nasal mucosal tissue and brain tissue. It was conducted to measure the concentration of AmB in TG-NE, in vitro, ex vivo and in vivo studies. The developed method was then validated based on ICH guidelines. The results obtained showed that the linear coefficient was ≥ 0.9998. The LLOQ values in MeOH, PBS + 2% SLS, nasal mucosa tissue and brain tissue were 1.63 µg/mL, 1.99 µg/mL, 1.55 µg/mL, 1.62 µg/mL, respectively. The accuracy and precision of the developed analytical method were found to be precise without the influence of dilution. Therefore, the method was successfully applied to measure the amount of AmB in TG-NE. The validated method was reported to be successful for measuring the amount of AmB in gel preparations, in vitro, ex vivo and in vivo studies showing uniformity of drug content, release profile and pharmacokinetic profile.

Pathways to care with HIV-associated cryptococcal meningitis in Botswana and Uganda: Findings from a qualitative methods study

HIV-associated cryptococcal meningitis remains a key driver of AIDS-related mortality. Mortality is twice as high in those who present later to care and with severe symptoms such as confusion. We embedded a qualitative methods study within a randomised controlled trial in Gaborone, Botswana and Kampala, Uganda with the aim of understanding pathways to care. We conducted in-depth interviews with trial participants and surrogate decision makers and analysed data thematically. Between January 2020 and June 2021 we interviewed 58 individuals. Pathways to care were prolonged because headaches were disregarded by participants and healthcare workers as a common occurrence with a broad differential diagnosis of predominantly benign aetiologies. There was also a lack of awareness of cryptococcal meningitis, and it was often after HIV was diagnosed or disclosed that the pathway accelerated, resulting in hospital admission. We outline key recommendations to reduce mortality and argue for the integration of social and behavioural interventions within differentiated service delivery models for advanced HIV disease.

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.

Preemptive Therapy in Cryptococcosis Adjusted for Outcomes

Cryptococcosis is one of the most serious opportunistic diseases in patients living with HIV. For this reason, early diagnosis and appropriate treatment are important.

OBJECTIVES

The aim of the study was to understand the development of patients diagnosed with cryptococcosis by detection of Cryptococcus antigen in serum by lateral flow assay (CrAg LFA) without nervous system involvement and with treatment in accordance with the results.

MATERIALS AND METHODS

A retrospective, longitudinal, analytical study was performed. Seventy patients with cryptococcosis initially diagnosed by serum CrAg LFA without meningeal involvement between January 2019 and April 2022 were analyzed for medical records. The treatment regimen was adapted to the results of blood culture, respiratory material, and pulmonary tomography imaging.

RESULTS

Seventy patients were included, 13 had probable pulmonary cryptococcosis, 4 had proven pulmonary cryptococcosis, 3 had fungemia, and 50 had preemptive therapy without microbiological or imaging findings compatible with cryptococcosis. Among the 50 patients with preemptive therapy, none had meningeal involvement or cryptococcosis recurrences to date.

CONCLUSION

Preemptive therapy avoided progression to meningitis in CrAg LFA-positive patients. Preemptive therapy with dose adjustment of fluconazole in patients with the mentioned characteristics was useful despite the use of lower doses than recommended.

Six months survival and risk factors for attrition for patients detected with cryptococcal antigenemia through screening in Malawi

MAIN OBJECTIVE

A cohort of adult Malawian people living with HIV (PLHIV) testing positive for cryptococcal antigenemia was observed and followed to determine the outcomes and risk factors for attrition.

METHODS CONCEPT

Eligible PLHIV were enrolled at 5 health facilities in Malawi, representing different levels of health care. ART naïve patients, ART defaulters returning to care, and patients with suspected or confirmed ART treatment failure with CD4 <200 cells/μL or clinical stage 3 or 4 were enrolled and received CrAg tests on whole blood specimens from August 2018 to August 2019. Hospitalized PLHIV were enrolled and tested for CrAg from January 2019 to August 2019, regardless of CD4 or clinical stage. Patients with cryptococcal antigenemia were managed per Malawian clinical guidelines and were followed up for six months. Survival and risk factors for attrition at six months were assessed.

RESULTS

A total of 2146 patients were screened and 112 (5.2%) had cryptococcal antigenemia. Prevalence ranged from 3.8% (Mzuzu Central Hospital) to 25.8% (Jenda Rural Hospital). Of the 112 patients with antigenemia, 33 (29.5%) were diagnosed with concurrent CM at the time of enrollment. Six-month crude survival of all patients with antigenemia (regardless of CM status) ranged from 52.3% (assuming lost-to-follow-up (LTFU) patients died) to 64.9% (if LTFU survived). Patients who were diagnosed with concurrent CM by CSF test had poor survival (27.3-39.4%). Patients with antigenemia who were not diagnosed with concurrent CM had 71.4% (if LTFU died)- 89.8% (if LTFU survived) survival at six months. In adjusted analyses, patients with cryptococcal antigenemia detected after admission to inpatient care (aHR: 2.56, 1.07-6.15) and patients with concurrent CM at the time of positive antigenemia result (aHR: 2.48, 1.04-5.92) had significantly higher hazard of attrition at six months.

CONCLUSIONS

Overall, our findings indicate a need for routine access to CrAg screening and pre-emptive fluconazole treatment as a way to detect cryptococcal antigenemia and prevent CM in outpatient and inpatient settings. Rapid access to diagnosis and treatment for cryptococcal meningitis (CM) with gold-standard antifungals is needed to improve survival of patients with advanced HIV in Malawi.

Effect of IL-10 in the pathogenesis of HIV/AIDS patients with cryptococcal meningitis

This study aimed to explore the role of IL-10 in the pathogenesis of HIV/AIDS patients with cryptococcal meningitis (CM).Patients were assigned into 4 groups (n = 40/group): group A (HIV/AIDS with CM), group B (HIV/AIDS with tuberculosis), group C (HIV/AIDS), and group D (CM). The levels of IL-10 and associated indicators were measured and the correlations were analyzed by Pearson correlation and partial correlation method. In plasma and cerebrospinal fluid (CSF), no significant difference was observed on IL-10 level between group A and other groups (P > 0.050). R values for IL-10 and relevant indicators in blood were as follows (P < 0.050): group A, IFN-γ (-0.377), IL-12 (0.743), IL-4 (0.881), and IL-6 (0.843); group B, IL-12 (0.740), IL-4 (0.573), and IL-6 (0.900); group C, IL-12 (0.402) and IL-4 (0.896); group D, IL-12 (0.575), IL-4 (0.852), and CD8 (0.325). R values for IL-10 and related indicators in CSF were as follows (P < 0.050): group A, TNF-α (0.664), IL-4 (0.852), white blood cells (WBCs, 0.321) and total protein (TP, 0.330); group B, TNF-α (0.566), IL-4 (0.702), and lactate dehydrogenase (LDH, 0.382); group D, IFN-γ (0.807) and IL-4 (0.441). IL-10 level was positively correlated with IL-4, IL-6, IL-12, TNF-α, WBC, and TP in blood or CSF, and negatively correlated with IFN-γ in blood, suggesting that IL-10 affected both pro-inflammatory and anti-inflammatory activities in the pathogenesis of HIV/AIDS with CM.

A multicenter survey of asymptomatic cryptococcal antigenemia among patients with advanced HIV disease in Nigeria

As of 2018, cryptococcal antigen (CrAg) screening in patients with advanced human immunodeficiency virus (HIV) disease (AHD) was not routinely implemented in Nigeria despite being recommended in the national HIV treatment guidelines. Our aim was to determine the prevalence and risk factors for asymptomatic cryptococcal antigenemia in adult people living with HIV (PLHIV) in Nigeria to advocate for the implementation of routine CrAg screening. A descriptive cross-sectional study and CrAg screening of consecutive adult PLHIV with CD4 counts ≤200 cells/μL was conducted from April 2018 to April 2019 at HIV clinics in eleven tertiary hospitals spread across Nigeria's six geopolitical regions. Prevalence of asymptomatic cryptococcal antigenemia was estimated by facility and geopolitical zone. Logistic regression was conducted to identify risk factors for cryptococcal antigenemia. In total, 1,114 patients with AHD were screened. The overall prevalence of asymptomatic cryptococcal antigenemia was 3.9% with wide variation across facilities (range: 0/75 [0%]- 15/122 [12.3%]) and geopolitical zones (range: 0/75 [0%]-19/279 [6.8%]). Prevalence of antigenemia was highest in the South-West (19/279 [6.8%]) and lowest in the North-East (0/75 [0%]). Prevalence was 5.2% (26/512) and 3.2% (18/561) in patients with CD4<100 and CD4 of 101-200, respectively. Of all patients with antigenemia, 50% were on antiretroviral therapy (ART) at the time of having a positive CrAg test. In adjusted analysis, cryptococcal antigenemia was significantly less in patients on ART and patients who had completed any formal education. The survey showed a high overall burden of cryptococcal antigenemia in Nigeria, with variable prevalence across geopolitical regions. We provided valuable evidence for implementing routine CrAg screening of AHD patients in Nigeria which has commenced in selected centres.

Prevalence of cryptococcal meningitis among people living with human immuno-deficiency virus and predictors of mortality in adults on induction therapy in Africa: A systematic review and meta-analysis

Background

Cryptococcal meningitis (CM) is a leading cause of adult meningitis in countries with a high burden of HIV. It has remained a significant cause of morbidity and mortality in Africa despite the extensive rollout of HIV antiretroviral therapy (ART). This study aimed to systematically synthesize the evidence on the prevalence of CM among people living with HIV (PLWH) and its predictors of mortality among adults who are on induction antifungal therapy in Africa.

Methods

PubMed/MEDLINE, Embase, and Google Scholar were searched for randomized clinical trials or observational studies published in Africa from 1995 to April 2021. Pooled prevalence of CM among PLWH was calculated using R-studio Version 1.4.1717 software and the data extracted from eligible studies were pooled as percentage with a 95% confidence interval (CI). Predictors of mortality among adults on induction antifungal therapy were synthesized narratively.

Results

Out of 364 studies identified, 17 eligible articles were included in the analysis. The prevalence of CM among PLWH in Africa was 5.11% (95% CI 2.71-9.43%; participants = 10,813; studies = 9; I 2 = 97%). In the subgroup analysis, the prevalence was 12.9% (95% CI 4.883-30.0; participants = 533; studies = 3; I 2 = 63%) in the years 1995-2010 and 3.18% (95% CI 1.54-6.45; participants = 10,280; studies = 6; I 2 = 98%) in the years 2011-2021, with the prevalence significantly decreased by 51% (p = 0.02). Predictors of mortality were fluconazole monotherapy, focal neurological signs, low Glasgow coma scale, and delayed diagnosis of CM at varied timepoint.

Conclusion

Prevalence of CM has significantly decreased from 1996-2010 to 2011-2021 among PLWH on induction therapy in Africa. Fluconazole monotherapy, focal neurological symptoms, diastolic blood pressure < 60 mmHg, and concurrent tuberculosis coinfection were significant predictors of mortality at 2- and 10-weeks timepoints. CM remains a major concern among PLWH despite increases in ART coverage. Improved access to effective antifungal therapies is needed in Africa for timely initiation of combination induction therapy and better treatment outcomes of PLWH.

Systematic review registration

[https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=254113], identifier [CRD42021254113].

COVID-19-associated opportunistic infections: a snapshot on the current reports

Treatment of the novel Coronavirus Disease 2019 (COVID-19) remains a complicated challenge, especially among patients with severe disease. In recent studies, immunosuppressive therapy has shown promising results for control of the cytokine storm syndrome (CSS) in severe cases of COVID-19. However, it is well documented that immunosuppressive agents (e.g., corticosteroids and cytokine blockers) increase the risk of opportunistic infections. On the other hand, several opportunistic infections were reported in COVID-19 patients, including Aspergillus spp., Candida spp., Cryptococcus neoformans, Pneumocystis jiroveci (carinii), mucormycosis, Cytomegalovirus (CMV), Herpes simplex virus (HSV), Strongyloides stercoralis, Mycobacterium tuberculosis, and Toxoplasma gondii. This review is a snapshot about the main opportunistic infections that reported among COVID-19 patients. As such, we summarized information about the main immunosuppressive agents that were used in recent clinical trials for COVID-19 patients and the risk of opportunistic infections following these treatments. We also discussed about the main challenges regarding diagnosis and treatment of COVID-19-associated opportunistic infections (CAOIs).

Point of care tests for invasive fungal infections: a blueprint for increasing availability in Africa

Invasive fungal infections (IFIs) such as cryptococcosis, disseminated histoplasmosis, and chronic pulmonary aspergillosis are significant causes of morbidity and mortality in Africa. Lack of laboratory infrastructure and laboratory personnel trained in diagnostic mycology hamper prompt detection and management of IFIs on the continent. Point-of-care tests (POCT) obviate the need for complex infrastructure, skilled technicians, and stable electricity and have had major impacts on the diagnosis of bacterial, viral, and parasitic infections in low- and middle-income countries. Over the last 10 years, POCTs for IFIs have become increasingly available and they have the potential to revolutionize the management of these infections if scaled up in Africa. At the beginning of 2021, the World Health Organization (WHO) Essential Diagnostic List (EDL) included a cryptococcal antigen test for the diagnosis of cryptococcosis, Histoplasma antigen test for the diagnosis of disseminated histoplasmosis, and Aspergillus-specific test for the diagnosis of chronic pulmonary aspergillosis. All of these are available in formats that may be used as POCTs and it is hoped that this will improve the diagnosis of these life-threatening IFIs, especially in low- and middle-income countries. This perspective review discusses commercially available POCTs and outlines strategies of a blueprint to achieve their roll-out in Africa. The strategies include raising awareness, conducting research that uncovers the exact burden of IFIs, increasing advocacy, integrating diagnosis of IFIs into existing public health programs, adoption of the WHO EDL at country levels, and improving logistics and supply chains.