Cryptococcal Antigen Screening in Asymptomatic HIV-Infected Antiretroviral Naïve Patients in Cameroon and Evaluation of the New Semi-Quantitative Biosynex CryptoPS Test

Current and emerging technologies to develop Point-of-Care Diagnostics in medical mycology

INTRODUCTION

Advances in diagnostic technologies, particularly Point-of-Care Diagnostics (POCDs), have revolutionized clinical practice by providing rapid, user-friendly, and affordable testing at or near the patient's location. POCDs have been increasingly introduced in medical mycology and hold promise to improve patient outcomes in a variety of important human fungal diseases.

AREAS COVERED

This review focuses on validated POCDs, particularly lateral flow assays (LFAs), for various fungal diseases. Additionally, we discuss emerging innovative techniques such as body fluid analysis, imaging methods, loop-mediated isothermal amplification (LAMP), microfluidic systems, clustered regularly interspaced short palindromic repeats (CRISPR)-based diagnostics, and the emerging role of artificial intelligence.

EXPERT OPINION

Compact and user-friendly POCDs have been increasingly introduced in medical mycology, and some of these tests (e.g. Cryptococcus and Histoplasma antigen LFAs) have become mainstream diagnostics, while others, such as LFA in invasive aspergillosis show promise to become part of our routine diagnostic armamentarium. POCDs offer immense benefits such as timely and accurate diagnostic results, reduced patient discomfort, and lower healthcare costs and might contribute to antifungal stewardship. Integrated fluidics combined with microtechnology having multiplex capabilities will be pivotal in medical mycology.

An evaluation of Mp1p antigen screening for talaromycosis in HIV-infected antiretroviral therapy-naïve population in Guangdong, China

BACKGROUND

Talaromycosis is one of the most common opportunistic infections in human immunodeficiency virus (HIV) infected patients. However, few researches have explored the prevalence in Southern China and fully assessed the value of the Mp1p antigen screening for the diagnosis of talaromycosis.

METHODOLOGY/PRINCIPAL FINDINGS

We performed a cross-sectional study of HIV-infected antiretroviral therapy (ART)-naïve adult patients who were seen in 2018 at Guangzhou Eighth People's Hospital, Guangzhou Medical University. Serum samples collected from all the 784 enrolled patients were tested for Mp1p antigen using double-antibody sandwich enzyme-linked immunosorbent assay. A culture of pathogen was conducted in 350 clinically suspected patients to confirm talaromycosis. The overall prevalence of talaromycosis based on the Mp1p antigen detection was 11.4% (89/784) and peaked at 32.2% (75/233) in patients with CD4+ ≤50 Nr/μl. Logistic regression analysis found Mp1p antigen positive rate decreased with the increase in CD4+ counts (OR 0.982, 95% CI 0.977-0.987, P<0.01). The optimal cut-off point of the CD4+ count was 50 Nr/μl or less. Among the 350 patients received both fungal culture and Mp1p antigen detection, 95/350 (27.1%) patients were culture-positive for a Talaromyces marneffei, 75/350 (21.4%) patients were Mp1p antigen positive. The Mp1p antigen assay showed a good agreement to the culture of pathogen, and the sensitivity, specificity, positive predictive value, negative predictive value and kappa value was 71.6% (68/95), 97.3% (248/255), 90.7% (68/75), 90.2% (248/275), and 0.737, respectively. The screening accuracy of the Mp1p antigen assay in patients with CD4+ counts of ≤50 Nr/μl was superior to that in those with higher CD4+ counts.

CONCLUSIONS/SIGNIFICANCE

Mp1p antigen screening can be an effective tool for more efficient diagnosis of Talaromycosis, especially in HIV/AIDS patients with low CD4+ counts. Future validation studies are needed.

Impact of prior cryptococcal antigen screening on in-hospital mortality in cryptococcal meningitis or fungaemia among HIV-seropositive individuals in South Africa: a cross-sectional observational study

OBJECTIVES

We investigated whether patients with cryptococcal meningitis (CM) or fungaemia detected through South Africa's laboratory cryptococcal antigen (CrAg) screening programme had better outcomes than those presenting directly to the hospital.

METHODS

We compared 14-day in-hospital case-fatality ratios of HIV-seropositive individuals with CD4 counts below 100 cells/μL and laboratory-confirmed CM/fungaemia from 2017-2021, with or without evidence of a positive blood CrAg test within 14 days prior to diagnosis. We evaluated whether the impact of prior CrAg screening on mortality varied according to the study period (pre-COVID-19: before March 2020 vs. COVID-19: after March 2020).

RESULTS

Overall, 24.5% (830/3390) of patients had a prior positive CrAg test within 14 days of diagnosis. CrAg-screened patients were less likely to have an altered mental status at baseline than non-CrAg-screened patients (38.1% [296/776] vs. 42.6% [1010/2372], p = 0.03), and had a lower crude 14-day case-fatality ratio (24.7% [205/830] vs. 28.3% [724/2560]; OR, 0.83 [95% CI, 0.69-0.99]; p = 0.045). Previous CrAg screening was associated with a greater reduction in the crude 14-day mortality during the COVID-19 period (OR, 0.64 [0.47-0.87]; p = 0.005) compared with before (OR, 0.95 [0.76-1.19]; p = 0.68). After adjustment, previous CrAg screening within 14 days was associated with increased survival only during the COVID-19 period (adjusted OR, 0.70 [0.51-0.96]; p = 0.03).

DISCUSSION

Previous CrAg screening was associated with a survival benefit in patients hospitalized with CM/fungaemia during the COVID-19 period, with fewer patients having an altered mental status at baseline, suggesting that these patients may have been diagnosed with cryptococcosis earlier.

Cryptococcal Antigenemia in Advanced Human Immunodeficiency Virus Disease: Pathophysiology, Epidemiology, and Clinical Implications

Cryptococcal antigen (CrAg) is detectable in blood prior to the onset of symptomatic cryptococcal meningitis (CM), a leading cause of death among people with advanced human immunodeficiency virus (HIV) disease globally. Highly sensitive assays can detect CrAg in blood, and screening people with HIV with low CD4 counts, followed by preemptive antifungal treatment, is recommended and widely implemented as part of a global strategy to prevent CM and end cryptococcal-related deaths. Cryptococcal antigenemia encompasses a spectrum of conditions from preclinical asymptomatic infection (cerebrospinal fluid [CSF] CrAg-negative) through subclinical (CSF CrAg-positive without overt meningism) to clinical symptomatic cryptococcal disease, usually manifesting as CM. In this review, we summarize current understanding of the pathophysiology, risk factors for, and clinical implications of cryptococcal antigenemia within this spectrum. We also provide an update on global prevalence, recommended screening and treatment strategies, and future considerations for improving outcomes among patients with cryptococcal antigenemia.

Cryptococcal antigenemia in people living with HIV and AIDS

AIM

To assess the prevalence of cryptococcal antigenemia among people living with HIV/AIDS (PLHA) with CD4 ≤100/mm³.

DESIGN

This observational study was performed on PLHA with laboratory-confirmed CD4 ≤100/mm³. All PLHA were recruited irrespective of their duration of HIV diagnosis, antiretroviral therapy (ART) naïve, or ART failure.

METHODS

The prevalence of cryptococcal antigen (CrAg) was assessed in 102 PLHA, with CD4 ≤100/mm³, using a latex agglutination test on serum samples. All the subjects were followed up for 3 months.

RESULTS

Amongst 102 PLHA, 62 (60.8%) and 40 (39.2%) patients were ART-naïve and ART failures, respectively, with 2.9% (n = 3) having clinical features of meningitis and 6.8% (n = 7) patients being asymptomatic CrAg-positive. At the 3 month follow-up, total mortality was 10.8%, of which 33.3% and 8.8% were among CrAg-positive and negative patients (p = 0.05). Mortality in asymptomatic and meningitis symptomatic CrAg-positive patients was 1.03% (n = 1) and 2.06% (n = 2), respectively. Of note, five patients were lost to follow-up.

CONCLUSION

Cryptococcal antigenemia is common among patients with CD4 ≤100/mm³ who were either ART naïve or had treatment failure. Asymptomatic patients who underwent pre-emptive therapy demonstrated good clinical outcomes.

Invasive Fungal Diseases in Africa: A Critical Literature Review

Invasive fungal diseases (IFDs) are of huge concern in resource-limited settings, particularly in Africa, due to the unavailability of diagnostic armamentarium for IFDs, thus making definitive diagnosis challenging. IFDs have non-specific systemic manifestations overlapping with more frequent illnesses, such as tuberculosis, HIV, and HIV-related opportunistic infections and malignancies. Consequently, IFDs are often undiagnosed or misdiagnosed. We critically reviewed the available literature on IFDs in Africa to provide a better understanding of their epidemiology, disease burden to guide future research and interventions. Cryptococcosis is the most encountered IFD in Africa, accounting for most of the HIV-related deaths in sub-Saharan Africa. Invasive aspergillosis, though somewhat underdiagnosed and/or misdiagnosed as tuberculosis, is increasingly being reported with a similar predilection towards people living with HIV. More cases of histoplasmosis are also being reported with recent epidemiological studies, particularly from Western Africa, showing high prevalence rates amongst presumptive tuberculosis patients and patients living with HIV. The burden of pneumocystis pneumonia has reduced significantly probably due to increased uptake of anti-retroviral therapy among people living with HIV both in Africa, and globally. Mucormycosis, talaromycosis, emergomycosis, blastomycosis, and coccidiomycosis have also been reported but with very few studies from the literature. The emergence of resistance to most of the available antifungal drugs in Africa is yet of huge concern as reported in other regions. IFDs in Africa is much more common than it appears and contributes significantly to morbidity and mortality. Huge investment is needed to drive awareness and fungi related research especially in diagnostics and antifungal therapy.

Interpretation, pitfalls of biomarkers in diagnosis of invasive fungal diseases

BACKGROUND

Invasive Fungal Diseases (IFD), account for high morbidity and mortality in immunocompromised and seriously ill patients worldwide. Early, faster and accurate diagnosis with timely and appropriate patient management is critical for improved patient outcome and antifungal stewardship. Clinical/radiological presentations in IFD are non-specific and microscopy/culture based tests have low sensitivity and long turnaround time. Biomarkers have clinical utility for diagnosing IFD but their interpretation is not straight forward.

OBJECTIVES

This review discusses the salient characteristics, clinical usefulness and limitations of common biomarkers such as Galactomannan (GM), 1-3, β D glucan (βDG), mannan, anti-mannan antibody (Mn/antiMn), Cryptococcal antigen test (CrAg), Nucleic Acid Amplification (NAA) tests and next generation sequencing for diagnosing IFD.

CONTENTS

Fungal biomarkers are useful adjuncts as screening and diagnostic tools for IFD and are much more suited for 'ruling out' rather than 'ruling in' disease. GM, NAA tests are promising biomarkers for screening of invasive Aspergillosis in high risk asymptomatic patients who are not on antifungal therapy and for diagnosis of breakthrough infections in symptomatic patients. 1-3, β D glucan has limitations both as a 'rule in' and 'rule out' test and is useful in only specific clinical settings. Two consecutive positive 1-3-βDG tests or combined positivity with GM increases its specificity. Mn/antiMn, T2Candida nano diagnostic panel are promising candidates for diagnosing invasive candidiasis. Combining two or more biomarkers improves the sensitivity for prompt initiation of antifungal therapy and the negative predictive value for suspension of empirical treatment. Serum CrAg test is a good 'rule in' rather than a 'rule out' test in immunocompetent patients but has good diagnostic accuracy in immunocompromised patients. Detection of single nucleotide polymorphisms by next generation sequencing is useful for fungal characterization and identification of host determinants responsible for increased susceptibility to fungal infections but is still in experimental stages.

Cryptococcal and Histoplasma Antigen Screening among People With HIV in Ghana and Comparative Analysis of OIDx Histoplasma Lateral Flow Assay and IMMY Histoplasma Enzyme Immunoassay

Background

Cryptococcal meningitis (CM) and disseminated histoplasmosis (DH) are common in people with HIV (PWH) and diagnosed by detecting cryptococcal antigen (CrAg) and Histoplasma antigen (Histo Ag) respectively. In Ghana, CM and DH are rarely suspected by clinicians due to limited epidemiological data.

Methods

This study was conducted among PWH in Ghana who are unwell. Sociodemographic and clinical data were collected by questionnaire. Serum and/or urine were screened for CrAg and Histo Ag, using IMMY CrAg lateral flow assay (LFA) and IMMY Histoplasma enzyme immunoassay (EIA) kits, respectively, regardless of symptoms. Samples run with IMMY Histoplasma EIA were simultaneously run with OIDx Histoplasma LFA. Laboratory investigations were conducted by the research team while diagnosis incorporating clinical assessment, screening and confirmatory testing results and treatment decisions were made by the clinical team. Treatment and outcome information on CM and DH patients were evaluated.

Results

Overall, 150 participants were recruited. There were 73% (n = 109) females, and the age range was 18–62 years. The prevalence rates of CrAg and Histo Ag were 2.7% (4/150) and 4.7% (5/107), respectively. The OIDx Histoplasma LFA showed a high concordance (98.4%) with the IMMY Histoplasma EIA. All antigen-positive cases by standard tests were diagnosed with CM and DH. Antifungal treatment was given in five patients and follow-up revealed two deaths and three recoveries.

Conclusion

Histoplasmosis among PWH may be more common than previously anticipated and may be more frequent than cryptococcosis in Ghana. The performance of the OIDx Histoplasma LFA should be further explored.

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.

Comparison of two commercial tests (Immy vs. Dynamiker) for cryptococcal capsular antigen

INTRODUCTION

Lateral flow assay is an advanced method useful in the early diagnosis of cryptococcal meningitis. We aimed to compare two commercial tests for cryptococcal capsular antigen in the sera of asymptomatic patients with human immunodeficiency virus in Barranquilla, Colombia.

METHODS

Thawed (n=162) previously collected serums (2016-2019) were processed using IMMY and Dynamiker cryptococcal antigen lateral flow assay.

RESULTS

Compared to IMMY's results, Dynamiker's sensitivity, specificity, positive predictive value, negative predictive value, and kappa index were 100%, 89.9%, 48.3%, 100.0%, and 0.61, respectively.

CONCLUSIONS

The Dynamiker test had excellent sensitivity, acceptable specificity, and a low detection threshold for cryptococcal antigen in the tested samples.

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.

Laboratory Reflex and Clinic-Based Point-of-Care Cryptococcal Antigen Screening for Preventing Meningitis and Mortality Among People Living With HIV

INTRODUCTION

Cryptococcosis remains a leading cause of meningitis and mortality among people living with HIV (PLHIV) worldwide. We sought to evaluate laboratory-based cryptococcal antigen (CrAg) reflex testing and a clinic-based point-of-care (POC) CrAg screening intervention for preventing meningitis and mortality among PLHIV in South Africa.

METHODS

We conducted a prospective pre-post intervention study of adults presenting for HIV testing in Umlazi township, South Africa, over a 6-year period (2013-2019). Participants were enrolled during 3 phases of CrAg testing: CrAg testing ordered by a clinician (clinician-directed testing, 2013-2015); routine laboratory-based CrAg reflex testing for blood samples with CD4 ≤100 cells/mm3 (laboratory reflex testing, 2015-2017); and a clinic-based intervention with POC CD4 testing and POC CrAg testing for PLHIV with CD4 ≤200 cells/mm3 with continued standard-of-care routine laboratory reflex testing among those with CD4 ≤100 cells/mm3 (clinic-based testing, 2017-2019). The laboratory and clinical teams performed serum CrAg by enzyme immunoassay and lateral flow assay (Immy Diagnostics, Norman, OK). We followed up participants for up to 14 months to compare associations between baseline CrAg positivity, antiretroviral therapy and fluconazole treatment initiation, and outcomes of cryptococcal meningitis, hospitalization, and mortality.

RESULTS

Three thousand one hundred five (39.4%) of 7877 people screened were HIV-positive, of whom 908 had CD4 ≤200 cells/mm3 and were included in the analyses. Laboratory reflex and clinic-based testing increased CrAg screening (P < 0.001) and diagnosis of CrAg-positive PLHIV (P = 0.011). When compared with clinician-directed testing, clinic-based CrAg testing showed an increase in the number of PLHIV diagnosed with cryptococcal meningitis (4.5% vs. 1.5%; P = 0.059), initiation of fluconazole preemptive therapy (7.2% vs. 2.5%; P = 0.010), and initiation of antiretroviral therapy (96.8% vs. 91.3%; P = 0.012). Comparing clinic-based testing with laboratory reflex testing, there was no significant difference in the cumulative incidence of cryptococcal meningitis (4.5% vs. 4.1%; P = 0.836) or mortality (8.1% vs. 9.9%; P = 0.557).

CONCLUSIONS

Laboratory reflex and clinic-based CrAg testing facilitated the diagnosis of HIV-associated cryptococcosis and fluconazole initiation but did not reduce cryptococcal meningitis or mortality. In this nonrandomized cohort, clinical outcomes were similar between laboratory reflex testing and clinic-based POC CrAg testing.

Cryptococcal antigen carriage among HIV infected children aged 6 months to 15 years at Laquintinie Hospital in Douala

Background

Up to 15% of deaths of people living with HIV is attributable to meningeal cryptococcosis, with nearly 75% occuring in sub-Saharan Africa. Although rare in children, it is a major cause of morbidity and mortality in people living with HIV. A strong association between cryptococcal antigenemia and the development of meningeal cryptococcosis has been shown in adults. Thus, in 2018, the World Health Organization published an updated version of its guidelines for the diagnosis, prevention and management of cryptococcal infection in adults, adolescents and the HIV-infected child.

Goal

To determine the prevalence of cryptococcal antigenemia and to identify its determinants in children infected with HIV.

Methods

An analytical cross-sectional study was carried out at the approved treatment center of Laquintinie hospital in Douala over a period of 4 months. Children were recruited consecutively after informed parental consent. Cryptococcal antigenemia and CD4 assay were performed using a Cryptops^® immunochromatographic rapid diagnostic test and flow cytometry, respectively. The data collected included the socio-demographic, clinical and paraclinical variables of the children, as well as their antecedents. Data analysis was performed using Epiinfo software version 3.1 and SPSS 21.0. The significance threshold was set at 5%.

Results

A total of 147 children were enrolled. The mean age was 9.8 ± 4.09 years. The majority were on antiretroviral therapy (142, 96.60%). Only 13 (8.80%) were in severe immunosuppression. No child showed signs of meningeal cryptococcosis. The prevalence of cryptococcal antigenemia was 6.12%. Severe immunosuppression [OR: 10.03 (1.52–65.91), p = 0.016] and contact with pigeons [OR: 9.76 (1.14–83.65), p = 0.037] were independent factors significantly associated with the carriage of the cryptococcal antigen.

Conclusion

We recommend screening for cryptococcal antigenemia and routine treatment with fluconazole of all HIV positive children with cryptococcal antigen whether symptomatic or not.

Cryptococcal Antigen in Serum and Cerebrospinal Fluid for Detecting Cryptococcal Meningitis in Adults Living With Human Immunodeficiency Virus: Systematic Review and Meta-Analysis of Diagnostic Test Accuracy Studies

Cryptococcal antigen (CrAg) detection could direct the timely initiation of antifungal therapy. We searched MEDLINE and Embase for studies where CrAg detection in serum/cerebrospinal fluid (CSF) and CSF fungal culture were done on adults living with human immunodeficiency virus (HIV) who had suspected cryptococcal meningitis (CM). With Quality Assessment of Diagnostic Accuracy Studies 2 (QUADAS-2), we evaluated the risk of bias in 11 included studies with 3600 participants, and used a random-effects meta-analysis to obtain summary sensitivity and specificity of serum and CSF CrAg, as well as agreement between CSF CrAg and CSF culture. Summary sensitivity and specificity of serum CrAg were 99.7% (97.4-100) and 94.1% (88.3-98.1), respectively, and summary sensitivity and specificity of CSF CrAg were 98.8% (96.2-99.6) and 99.3% (96.7-99.9), respectively. Agreement between CSF CrAg and CSF culture was 98% (97-99). In adults living with HIV who have CM symptoms, serum CrAg negativity may rule out CM, while positivity should prompt induction antifungal therapy if lumbar puncture is not feasible. In a first episode of CM, CSF CrAg positivity is diagnostic.

Dormancy in Cryptococcus neoformans: 60 years of accumulating evidence

Cryptococcus neoformans is an opportunistic yeast that is present worldwide and interacts with various organisms. In humans, it is responsible for cryptococcosis, a deadly invasive fungal infection that represents around 220,000 cases per year worldwide. Starting from the natural history of the disease in humans, there is accumulating evidence on the capacity of this organism to enter dormancy. In response to the harsh host environment, the yeast is able to adapt dramatically and escape the vigilance of the host's immune cells to survive. Indeed, the yeast exposed to the host takes on pleiotropic phenotypes, enabling the generation of populations in heterogeneous states, including dormancy, to eventually survive at low metabolic cost and revive in favorable conditions. The concept of dormancy has been validated in C. neoformans from both epidemiological and genotyping data, and more recently from the biological point of view with the characterization of dormancy through the description of viable but nonculturable cells.

Diagnostic Accuracy of the Biosynex CryptoPS Cryptococcal Antigen Semiquantitative Lateral Flow Assay in Patients with Advanced HIV Disease

High cryptococcal antigen (CrAg) titers in blood are associated with subclinical meningitis and mortality in CrAg-positive individuals with advanced HIV disease (AHD). We evaluated a novel semiquantitative lateral flow assay (LFA), CryptoPS, that may be able to identify individuals with high CrAg titers in a cohort of AHD patients undergoing CrAg screening. In a prospective cohort of patients with AHD (CD4 cell count, ≤200/μl) receiving CD4 count testing, whole blood was tested for CrAg by CryptoPS and the IMMY LFA; the two assays were conducted by two different operators, each blind to the results of the other assay.

High cryptococcal antigen (CrAg) titers in blood are associated with subclinical meningitis and mortality in CrAg-positive individuals with advanced HIV disease (AHD). We evaluated a novel semiquantitative lateral flow assay (LFA), CryptoPS, that may be able to identify individuals with high CrAg titers in a cohort of AHD patients undergoing CrAg screening. In a prospective cohort of patients with AHD (CD4 cell count, ≤200/μl) receiving CD4 count testing, whole blood was tested for CrAg by CryptoPS and the IMMY LFA; the two assays were conducted by two different operators, each blind to the results of the other assay. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of CryptoPS were assessed against the IMMY LFA as a reference. CryptoPS low-titer (T1 band) and high-titer (T2 band) results were compared with IMMY LFA titers obtained through serial dilution. A total of 916 specimens were tested. The sensitivity of the CryptoPS assay was 61.0% (25/41) (95% confidence interval [95% CI], 44.5 to 75.8%), its specificity was 96.6% (845/875) (95% CI, 95.1 to 97.7%), its PPV was 45.5% (95% CI, 32.0 to 59.4%), and its NPV was 98.1% (95% CI, 97.0 to 98.9%). All (16/16) CryptoPS false-negative results were obtained for samples with IMMY titers of ≤1:160. Of 29 patients (30 specimens) who tested positive by CryptoPS but negative by the IMMY LFA, none developed cryptococcal meningitis over 3 months of follow-up without fluconazole. Median CrAg titers were 1:20 (interquartile range [IQR], 0 to 1:160) in CryptoPS T1-positive samples and 1:2,560 (IQR, 1:1,280 to 1:10,240) in T2-positive samples. We conclude that the diagnostic accuracy of the CryptoPS assay was suboptimal in the context of CrAg screening, with poor sensitivity at low CrAg titers. However, the CryptoPS assay reliably detected individuals with high titers, which are associated with poor outcomes.

Cryptococcal infection in HIV-infected patients with CD4+ T-cell counts under 100/μL diagnosed in a high-income country: a multicentre cohort study

OBJECTIVES

The World Health Organization recommends routinely screening HIV-infected patients with CD4⁺ T-cell counts <100/μL for cryptococcal infection to prevent cryptococcal meningitis (CM), based on studies in Sub-Saharan Africa where the prevalence of positive cryptococcal antigen (CrAg+) is ≥ 3% in this subgroup. Data about such prevalence in Spain are unavailable and rare in other European countries. Thus, the Spanish AIDS Study Group guidelines do not recommend routinely screening. We aim to determine the prevalence and outcomes of cryptococcal infection in this subgroup of patients in Spain.

METHODS

We determined CrAg using a lateral flow assay in banked plasma from participants in the cohort of the Spanish AIDS Research Network. Eligible patients had CD4⁺ T-cell counts ≤100/μL at the time of plasma collection and a follow-up >4 weeks, unless they died.

RESULTS

We included 576 patients from June 2004 to December 2017. Of these, 43 were CrAg+ for an overall prevalence of 7.5%. There were no differences depending on birthplace. The CrAg+ was independently associated with a higher mortality at eight weeks (hazard ratio (HR) 5.36, 95% confidence interval (CI) 1.46-19.56) and 6 months (HR 3.12, 95% CI 1.19-8.21). CM was reported in 10 of the 43 CrAg+ patients. There were no cases among negatives. Five patients had CM when the plasma was collected and five developed it during the follow-up. The number of subjects needed to screen to anticipate the diagnosis of one CM case was 114.

CONCLUSIONS

The CrAg+ prevalence among HIV-infected patients with CD4⁺ T-cell counts ≤100/μL diagnosed in Spain, both immigrants and native-born Spanish, is >7%. Consequently, the Spanish AIDS Study Group guidelines have to be updated and recommend routine screening for cryptococcal infection in these patients. Future studies should explore whether this recommendation could be firmly applied to other European populations.

Evaluation of lateral flow immunochromatographic assay for diagnostic accuracy of cryptococcosis

Background

Cryptococcus is a conditional pathogenic fungus causing cryptococcosis, which is one of the most serious fungal diseases faced by humans. Lateral flow immunochromatographic assay (LFA) is successfully applied to the rapid detection of cryptococcal antigens.

Methods

Studies were retrieved systematically from the Embase, PubMed, Web of Science, and Cochrane Library before July 2019. The quality of the studies was assessed by Review Manager 5.0 based on the Quality Assessment of Diagnostic Accuracy Study guidelines. The extracted data from the included studies were analyzed by Meta-DiSc 1.4. Stata 12.0 software was used to detect the publication bias.

Results

A total of 15 articles with 31 fourfold tables were adopted by inclusion and exclusion criteria. The merged sensitivity and specificity in serum were 0.98 and 0.98, respectively, and those in the cerebrospinal fluid were 0.99 and 0.99, respectively.

Conclusions

Compared to the urine and other samples, LFA in serum and cerebrospinal fluid is favorable evidence for the diagnosis of cryptococcosis with high specificity and sensitivity.

Cryptococcal infection in haematologic malignancies and haematopoietic stem cell transplantation

This review summarises both the recent and relevant studies about cryptococcal infections in haematologic malignancies and haematopoietic stem cell transplantation. Although uncommon in this patient population, this infection carries a high mortality, especially if left untreated. Given the limited data, we draw some conclusions with respect to management from the solid organ transplantation and HIV-infected literature. Herein, we discuss cryptococcosis with a particular attention to its background, epidemiology, risk factors, clinical presentation, diagnosis, treatment and prevention in this group.

Oral mycobiome identification in atopic dermatitis, leukemia, and HIV patients - a systematic review

INTRODUCTION

Oral mycobiome profiling is important to understand host-pathogen interactions that occur in various diseases. Invasive fungal infections are particularly relevant for patients who have received chemotherapy and for those who have HIV infection. In addition, changes in fungal microbiota are associated with the worsening of chronic conditions like atopic dermatitis (AD). This work aims, through a systematic review, to analyze the methods used in previous studies to identify oral fungi and their most frequent species in patients with the following conditions: HIV infection, leukemia, and atopic dermatitis.

METHODS

A literature search was performed on several different databases. Inclusion criteria were: written in English or Portuguese; published between September 2009 and September 2019; analyzed oral fungi of HIV-infected, leukemia, or AD patients.

RESULTS

21 studies were included and the most identified species was Candida. The predominant methods of identification were morphological (13/21) and sugar fermentation and assimilation tests (11/21). Polymerase chain reaction (PCR) was the most used molecular method (8/21) followed by sequencing techniques (3/21).

CONCLUSIONS

Although morphological and biochemical tests are still used, they are associated with high-throughput sequencing techniques, due to their accuracy and time saving for profiling the predominant species in oral mycobiome.

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

INTRODUCTION

Cryptococcal meningitis remains a significant contributor to AIDS-related mortality despite widened access to antiretroviral therapy. Cryptococcal antigen (CrAg) can be detected in the blood prior to development of meningitis. Development of highly sensitive and specific rapid diagnostic CrAg tests has helped facilitate the adoption of CrAg screening programs in 19 African countries.

AREAS COVERED

The biological rationale for CrAg screening and the programmatic strategies for its implementation are reviewed. We describe the approach to the investigation of patients with cryptococcal antigenemia and the importance of lumbar puncture to identify individuals who may have cryptococcal meningitis in the absence of symptoms. The limitations of current treatment recommendations and the potential role of newly defined combination antifungal therapies are discussed. A literature review was conducted using a broad database search for cryptococcal antigen screening and related terms in published journal articles dating up to December 2019. Conference abstracts, publicly available guidelines, and project descriptions were also incorporated.

EXPERT OPINION

As we learn more about the risks of cryptococcal antigenemia, it has become clear that the current management paradigm is inadequate. More intensive investigation and management are required to prevent the development of cryptococcal meningitis and reduce mortality associated with cryptococcal antigenemia.

Framework for the implementation of advanced HIV disease diagnostics in sub-Saharan Africa: programmatic perspectives

Patients with advanced HIV disease have a high risk of mortality, mainly from tuberculosis and cryptococcal meningitis. The advanced HIV disease management package recommended by WHO, which includes diagnostics, therapeutics, and patient psychosocial support, is barely implemented in many different countries. Here, we present a framework for the implementation of advanced HIV disease diagnostics. Laboratory and point-of-care-based reflex testing, coupled with provider-initiated requested testing, for cryptococcal antigen and urinary Mycobacterium tuberculosis lipoarabinomannan antigen, should be done for all patients with CD4⁺ cell counts of 200 cells per μL or less. Implementation of the advanced HIV disease package should be encouraged within primary health-care facilities and task shifting of testing to lay cadres could facilitate access to rapid results. Implementation of differentiated antiretroviral therapy delivery models can allow clinicians enough time to focus on the management of patients with advanced HIV disease. Efficient up-referral and post-discharge systems, including the development of patient-centric advanced HIV disease literacy, are also crucial. Implementation of the advanced HIV disease package is feasible at all health-care levels, and it should be part of the core of the global response towards ending AIDS as a public health threat.

Cryptococcal-related Mortality Despite Fluconazole Preemptive Treatment in a Cryptococcal Antigen Screen-and-Treat Program

BACKGROUND

Cryptococcal antigen (CrAg) screening and treatment with preemptive fluconazole reduces the incidence of clinically evident cryptococcal meningitis in individuals living with advanced human immunodeficiency virus (HIV) disease. However, mortality remains higher in CrAg-positive than in CrAg-negative patients with similar CD4+ T-lymphocyte counts.

METHODS

We conducted a cohort study to investigate causes of morbidity and mortality during 6 months of follow-up among asymptomatic CrAg-positive and CrAg-negative (ratio of 1:2) patients living with HIV with CD4 counts <100 cells/µL attending 2 hospitals in Johannesburg, South Africa. When possible, minimally invasive autopsy (MIA) was performed on participants who died.

RESULTS

Sixty-seven CrAg-positive and 134 CrAg-negative patients were enrolled. Death occurred in 17/67 (25%) CrAg-positive and 12/134 (9%) CrAg-negative participants (hazard ratio for death, adjusted for CD4 count, 3.0; 95% confidence interval, 1.4-6.7; P = .006). Cryptococcal disease was an immediate or contributing cause of death in 12/17 (71%) CrAg-positive participants. Postmortem cryptococcal meningitis and pulmonary cryptococcosis were identified at MIA in all 4 CrAg-positive participants, 3 of whom had negative cerebrospinal fluid CrAg tests from lumbar punctures (LPs) at the time of CrAg screening.

CONCLUSIONS

Cryptococcal disease was an important cause of mortality among asymptomatic CrAg-positive participants despite LPs to identify and treat those with subclinical cryptococcal meningitis and preemptive fluconazole for those without meningitis. Thorough investigation for cryptococcal disease with LPs and blood cultures, prompt ART initiation, and more intensive antifungals may reduce mortality among asymptomatic CrAg-positive patients identified through screening.

Evaluation of Serum Cryptococcal Antigen Testing Using Two Novel Semiquantitative Lateral Flow Assays in Persons with Cryptococcal Antigenemia

Early cryptococcal disease can be detected via circulating antigen in blood before fulminant meningitis develops, when early antifungal therapy improves survival. Two semiquantitative cryptococcal antigen (CrAg) lateral flow assays (LFAs) have been developed, but their diagnostic performance has not been defined. Cryopreserved serum samples from HIV-infected Ugandans obtained as part of a prospective CrAg-screening cohort were tested in duplicate for CrAg by the CrAgSQ (IMMY) and CryptoPS (Biosynex) lateral flow assays. Case-controlled diagnostic performance was measured using the FDA-approved CrAg LFA (IMMY) as a reference standard via McNemar's test. Of 99 serum samples tested, 57 were CrAg positive (CrAg⁺) by the CrAg LFA reference standard. By CrAgSQ, 57 were read as positive, with 98% sensitivity (56/57; 95% confidence interval [CI], 0.91 to 0.99) and 98% specificity (41/42; 95% CI, 0.88 to 0.99) (McNemar's, P = 0.99). The sample with a false-negative result by CrAgSQ (n = 1) had a titer of <1:5, while the sample with a false-positive result (n = 1) yielded a 1+ result. By CryptoPS, 52 samples were read as positive, with 88% sensitivity (50/57; 95% CI, 0.76 to 0.95) and 95% specificity (40/42; 95% CI, 0.84 to 0.99) (McNemar's, P = 0.18). The CryptoPS false-negative results included samples with titers of <1:5 (n = 1), 1:5 (n = 5), and 1:20 (n = 1), while samples with false-positive results by CryptoPS (n = 2) yielded Positive results. The CryptoPS assay missed 35% (7/20) of samples with CrAg LFA titers of ≤1:20. The new semiquantitative CrAg LFAs allow rapid estimation of titer levels in easy-to-perform platforms. The CrAgSQ demonstrated better qualitative sensitivity and specificity than the CryptoPS compared to the reference standard. The exact grading of the CrAgSQ results has some subjectivity, with interreader variability; however, qualitative reads were generally concordant for both assays.

Impact of Routine Cryptococcal Antigen Screening and Targeted Preemptive Fluconazole Therapy in Antiretroviral-naive Human Immunodeficiency Virus-infected Adults With CD4 Cell Counts <100/μL: A Systematic Review and Meta-analysis

Cryptococcal antigen (CrAg) screening and targeted preemptive fluconazole in antiretroviral-naive human immunodeficiency virus-infected adults with CD4 cell counts <100/μL seems promising as a strategy to reduce the burden of cryptococcal meningitis (CM). We searched MEDLINE, EMBASE, and Web of Science and used random-effect meta-analysis to assess the prevalence of blood CrAg positivity (31 studies; 35644 participants) and asymptomatic CM in CrAg-positive participants and the incidence of CM and the all-cause mortality rate in screened participants. The pooled prevalence of blood CrAg-positivity was 6% (95% confidence interval [CI], 5%-7%), and the prevalence of asymptomatic CM in CrAg-positive participants was 33% (95% CI, 21%-45%). The incidence of CM was 21.4% (95% CI, 11.6%-34.4%) without preemptive fluconazole and 5.7% (95% CI, 3.0%-9.7%) with preemptive fluconazole therapy initiated at 800 mg/d. In CrAg-positive participants, postscreening lumbar puncture before initiating preemptive fluconazole at 800 mg/d further reduced the incidence of CM to null and showed some survival benefits. However, the all-cause mortality rate remained significantly higher in CrAg-positive than in CrAg-negative participants (risk ratio, 2.2; 95% CI, 1.7-2.9; P < .001).

Emerging concepts in HIV-associated cryptococcal meningitis

PURPOSE OF REVIEW

HIV-associated cryptococcal meningitis remains a significant contributor to AIDS-related mortality despite widened access to antiretroviral therapy. Even in clinical trial settings 10-week mortality is roughly 40%. A number of important clinical trials have either recently concluded or are actively recruiting.

RECENT FINDINGS

Global burden of disease estimates suggest cryptococcal meningitis causes 181 100 deaths annually. Screening blood for cryptococcal antigen in HIV-infected individuals with CD4 cell counts less than 100 cells/μl and preemptive antifungal treatment for those with detectable cryptococcal antigen reduces the incidence of cryptococcal meningitis and is likely to reduce mortality. Cryptococcal meningitis treatment with conventional 14-day courses of amphotericin are associated with high toxicity and mortality and can be reduced to 7 days if given alongside flucytosine. Flucytosine is a significantly superior adjunct to amphotericin treatment compared with fluconazole. In settings without amphotericin B dual oral antifungal combinations of flucytosine and fluconazole offer an effective alternative treatment. A single, high-dose of liposomal amphotericin is effective at reducing fungal burden and is being tested in a phase III trial.

SUMMARY

Recently completed and ongoing clinical trials are increasing our understanding of how to optimize induction therapy for cryptococcal meningitis. Advocacy efforts are needed to broaden access to amphotericin formulations and flucytosine.

Cryptococcus neoformans seropositivity and some haematological parameters in HIV seropositive subjects

BACKGROUND

Cryptococcus neoformans is an opportunistic fungal pathogen that causes meningitis worldwide and may be fatal in immunocompromised subjects. In Nigeria, cases have been reported with prevalence between 4 and 13.1% in Human Immunodeficiency virus (HIV) patients depending on the study subjects. This study was designed to assess the prevalence of cryptococcosis, CD4+T cell counts and possible effect on haematological parameters in HIV seropositive subject in Nnewi, South-Eastern Nigeria.

METHOD

A total of four hundred and twenty-nine (429) subjects were recruited for the study. Of these, two hundred and ninety (290) were HIV positive and one hundred and thirty-nine (139) were HIV seronegative subjects recruited from the voluntary counseling and testing (VCT) unit and HIV care clinic at Nnamdi Azikiwe University Teaching Hospital Nnewi, Anambra State, Nigeria. Their ages were between 18-80 years. One hundred and thirty nine (139) apparently healthy HIV seronegative subjects were recruited as controls. Blood samples were taken for C. neoformans by Antigen lateral flow assay (CrAgLFA), HIV testing, CD4+T cell, platelet and Full blood count (FBC).

RESULTS

Our results show that of the two hundred and ninety (290) who were HIV positive subjects investigated for cryptococcosis, 4 (1.4%) tested positive for CrAg of whom 1(25%) were male and 3(75%) were female. All those with cryptococcosis had their CD4 count below 200 cells/μL, three of them were on ART and one was not. There were significant differences in the CD4 counts (P<0.05) between those infected and not infected with C. neoformans. None of the control group tested positive to cryptococcosis.

CONCLUSION

Widespread use of anti-retroviral therapy may have reduced C. neoformans infection. However, the threat remains and there may be a possibility that women may be a more vulnerable population.

New Insights Into Cryptococcus Spp. Biology and Cryptococcal Meningitis

PURPOSE OF REVIEW

Defective cell-mediated immunity is a major risk factor for cryptococcosis, a fatal disease if untreated. Cryptococcal meningitis (CM), the main presentation of disseminated disease, occurs through hematogenous spread to the brain from primary pulmonary foci, facilitated by yeast virulence factors. We revisit remarkable recent improvements in the prevention, diagnosis and management of CM.

RECENT FINDINGS

Cryptococcal antigen (CrAg), main capsular polysaccharide of Cryptococcus spp. is detectable in blood and cerebrospinal fluid of infected patients with point of care lateral flow assays. Recent World Health Organization guidelines recommend 7-day amphotericin B plus flucytosine, then 7-day high dose (1200 mg/day) fluconazole for induction treatment of HIV-associated CM. Management of raised intracranial pressure, a consequence of CM, should rely mainly on daily therapeutic lumbar punctures until normalisation. In HIV-associated CM, following introduction of antifungal therapy, (re)initiation of antiretroviral therapy should be delayed by 4-6 weeks to prevent immune reconstitution inflammatory syndrome, common in CM. CM is a fatal disease whose diagnosis has recently been simplified. Treatment should always include antifungal combination therapy and management of raised intracranial pressure. Screening for immune deficiency should be mandatory in all patients with cryptococcosis.

Evaluation of the clinical performance of 2 point-of-care cryptococcal antigen tests in dogs and cats

Background

Point‐of‐care (POC) Cryptococcus antigen assays may provide veterinarians with a more rapid, patient‐side diagnosis when compared with traditional laboratory‐based latex agglutination tests.

Objective

To determine the sensitivity and specificity of 2 POC lateral flow cryptococcal serum antigen tests, CrAg LFA (Immy, Norman, OK) and the CryptoPS (Biosynex, Strasbourg, France) for diagnosis of cryptococcosis in dogs and cats, using the cryptococcal antigen latex agglutination system (CALAS) as the reference standard.

Animals

102 serum samples from 51 dogs and 40 cats.

Methods

Specimens were classified as CALAS‐positive (n = 25) or CALAS‐negative (n = 77). The sensitivity and specificity of each POC assay was calculated by comparing the results to the serologic reference standard results.

Results

The CrAg LFA assay correctly classified 23/25 CALAS‐positive specimens and 69/74 CALAS‐negative specimens resulting in a sensitivity of 92.0% (confidence interval [CI], 75.0%‐98.6%) and specificity of 93.2% (CI, 85.1%‐97.1%). The CryptoPS assay correctly classified 8/10 tested CALAS‐positive specimens and 56/59 tested CALAS‐negative specimens resulting in a sensitivity of 80.0% (CI, 49.0%‐96.5%) and specificity of 94.9% (CI, 86.1%‐98.6%).

Conclusion and Clinical Importance

The POC assays appear to be a sensitive and specific alternative to the traditional CALAS assay with more rapid turnaround times, which may result in earlier diagnosis and treatment.

Identification of Cryptococcus antigen in human immunodeficiency virus-positive Turkish patients by using the Dynamiker® lateral flow assay

Cryptococcus neoformans causes life-threatening meningoencephalitis, particularly in human immunodeficiency virus (HIV)-positive individuals with low CD4 levels (<100 cells/μL). Although the burden of cryptococcal meningoencephalitis (CM) in Turkey is low (0.13 cases per 100 000 persons), asymptomatic individuals at risk of cryptococcosis should be screened for antigenemia to prevent the disease and/or promote early CM diagnosis. A lateral flow assay (LFA) is used to detect Cryptococcus antigen (CrAg) in cerebrospinal fluid and serum. We determined Cryptococcus antigenemia prevalence in serum samples of HIV-positive and HIV-negative adult patients by using Dynamiker® CrAg-LFA, a point-of-care dipstick test. Patients' demographic data, CD4 count, HIV-RNA levels and anti-retroviral therapy status were recorded. CrAg was detected in 28 (11%) of 254 HIV-positive patients screened but not in 100 HIV-negative control individuals; a significant difference was observed in the CrAg-LFA positivity rate between HIV-positive and HIV-negative groups (x²  = 11.970; P < .05). In CrAg-positive patients, the median CD4 level was 666 cells/μL (115-1344 cells/μL), with a median viral load of 23 copies/mL (0-3.69 × 10⁶  copies/mL). In HIV-positive CrAg-negative patients, the median CD4 level was 633 cells/μL (31-2953 cells/μL) and the median viral load was 12 copies/mL (0-1.95 × 10⁶  copies/mL; P > .05). Results indicate that HIV-positive patients with both low (<200 cells/μL) and high (>200 cells/μL) CD4 counts should be screened for asymptomatic cryptococcal antigenemia. HIV-associated asymptomatic cryptococcosis is not uncommon in Turkey, which warrants systematic screening. Updated strategies for CM prevention among HIV-positive patients should be used even in non-endemic countries.

Leave no one behind: response to new evidence and guidelines for the management of cryptococcal meningitis in low-income and middle-income countries

In 2018, WHO issued guidelines for the diagnosis, prevention, and management of HIV-related cryptococcal disease. Two strategies are recommended to reduce the high mortality associated with HIV-related cryptococcal meningitis in low-income and middle-income countries (LMICs): optimised combination therapies for confirmed meningitis cases and cryptococcal antigen screening programmes for ambulatory people living with HIV who access care. WHO's preferred therapy for the treatment of HIV-related cryptococcal meningitis in LMICs is 1 week of amphotericin B plus flucytosine, and the alternative therapy is 2 weeks of fluconazole plus flucytosine. In the ACTA trial, 1-week (short course) amphotericin B plus flucytosine resulted in a 10-week mortality of 24% (95% CI -16 to 32) and 2 weeks of fluconazole and flucytosine resulted in a 10-week mortality of 35% (95% CI -29 to 41). However, with widely used fluconazole monotherapy, mortality because of HIV-related cryptococcal meningitis is approximately 70% in many African LMIC settings. Therefore, the potential to transform the management of HIV-related cryptococcal meningitis in resource-limited settings is substantial. Sustainable access to essential medicines, including flucytosine and amphotericin B, in LMICs is paramount and the focus of this Personal View.

Invasive fungal infection by Cryptococcus neoformans var. grubii with bone marrow and meningeal involvement in a HIV-infected patient: a case report

Background

Cryptococcosis is a common opportunistic infection in patients infected by Human Immunodeficiency Virus (HIV) and is the second leading cause of mortality in Acquired Immunodeficiency Syndrome (AIDS) patients worldwide. The most frequent presentation of cryptococcal infection is subacute meningitis, especially in patients with a CD4+ T Lymphocytes count below 100 cells/μL. However, in severely immunosuppressed individuals Cryptococcus neoformans can infect virtually any human organ, including the bone marrow, which is a rare presentation of cryptococcosis.

Case presentation

A 45-year-old HIV-infected male patient with a CD4+ T lymphocyte count of 26 cells/μL who presented to the emergency department with fever and pancytopenia. Throughout the diagnostic evaluation, the bone marrow aspirate culture yielded encapsulated yeasts in budding, identified as Cryptococcus sp. The bone marrow biopsy revealed a hypocellularity for age and absence of fibrosis. It was observed presence of loosely formed granuloma composed of multinucleated giant cells encompassing rounded yeast like organisms stained with mucicarmine, compatible with Cryptococcus sp. Then, the patient underwent a lumbar puncture to investigate meningitis, although he had no neurological symptoms and neurological examination was normal. The cerebrospinal fluid culture yielded Cryptococcus sp. The species and genotype identification step showed the infection was caused by Cryptococcus neoformans var. grubii (genotype VNI). The patient was initially treated with amphotericin B deoxycholate plus fluconazole for disseminated cryptococcosis, according to guideline recommendations. However, the patient developed acute kidney injury and the treatment was switched for fluconazole monotherapy. The symptoms disappeared completely with recovery of white blood cells and platelets counts. Cerebrospinal fluid cultures for fungi at one and two-weeks of treatment were negative.

Conclusions

Bone marrow infection caused by Cryptococcus neoformans is a rare presentation of cryptococcosis. The cryptococcal infection should be included for differential diagnosis in HIV-infected patients with fever and cytopenias, especially when CD4+ T lymphocytes count is below 100 cells/μL.

Validation of clinic-based cryptococcal antigen lateral flow assay screening in HIV-infected adults in South Africa

Since rapid cryptococcal antigen lateral flow assays (CrAg LFA) may expedite treatment of HIV-associated cryptococcal infections, we sought to validate clinic-based CrAg LFA testing. Among newly-diagnosed HIV-infected adults in South Africa, a trained nurse performed clinic-based testing of urine, fingerprick capillary and venous whole blood with rapid CrAg LFA (Immy Diagnostics, Norman, USA). We performed matched laboratory-based serum cryptococcal antigen testing with an enzyme immunoassay (EIA). We assessed diagnostic accuracy using EIA as the gold-standard, and performed additional validation testing on serum and among hospitalized adults with cryptococcal meningitis. Among 5,618 participants enrolled, 1,296 were HIV-infected and screened for cryptococcal antigenemia. Overall CrAg prevalence by serum EIA was 3.6% (95% CI 2.0–6.0%) for adults with CD4 < 200 cells/mm³, and 5.7% (95% CI 2.8–10.2%) for adults with CD4 < 100 cells/mm³. Using expanded screening guidelines (CD4 < 200 cells/mm³), CrAg LFA testing of venous whole blood, fingerprick capillary blood, and urine had diagnostic sensitivities of 46% (95% CI 19–75%), 38% (95% CI 14–68%), and 54% (95% CI 25–81%), and specificities of 97%, 97%, and 86%, respectively. When tested on serum samples, CrAg LFA had sensitivity of 93% (95% CI 66–100%) and specificity of 100% (95% CI 88–100%). All venous and fingerprick whole blood CrAg LFA tests were positive among 30 hospitalized adults with cryptococcal meningitis. Two independent readers had strong agreement for all LFA results (p < 0.0001). When performed at the point-of-care by trained nurses, CrAg LFA testing was feasible, had the highest accuracy on serum specimens, and may accelerate treatment of HIV-associated cryptococcal infections.

Development of a lateral flow recombinase polymerase amplification assay for rapid and visual detection of Cryptococcus neoformans/C. gattii in cerebral spinal fluid

Background

For definitive diagnosis of cryptococcal meningitis, Cryptococcus neoformans and/or C. gattii must be identified within cerebral spinal fluid from the patients. The traditional methods for detecting Cryptococcus spp. such as India ink staining and culture are not ideal. Although sensitive and specific enough, detection of cryptococcal antigen polysaccharide has a high dose hook effect. Therefore, the aim of this study was to introduce a new rapid and simple detection method of Cryptococcus neoformans and C. gattii in cerebral spinal fluid.

Methods

The lateral flow strips combined with recombinase polymerase amplification (LF-RPA) assay was constructed to detect the specific DNA sequences of C. neoformans and C. gattii. The detection limit was evaluated using serial dilutions of C. neoformans and C. gattii genomic DNA. The specificity was assessed by excessive amount of other pathogens genomic DNA. The optimal detection time and amplification temperature were also analyzed. The diagnostic parameters were first calculated using 114 clinical specimens and then compared with that of other diagnostic method. A brief analysis and comparison of different DNA extraction methods was discussed, too.

Results

The LF-RPA assay could detect 0.64 pg of genomic DNA of C. neoformans per reaction within 10 min and was highly specific for Cryptococcus spp.. The system could work well at a wide range of temperature from 25 to 45 °C. The overall sensitivity and specificity were 95.2 and 95.8% respectively. As amplification template for LF-RPA assay, both cell lysates and genomic DNA produce similar experimental results.

Conclusions

The LF-RPA system described here is shown to be a sensitive and specific method for the visible, rapid, and accurate detection of Cryptococcus spp. in cerebral spinal fluid and might be useful for clinical preliminary screening of cryptococcal meningitis.

Cryptococcal Meningitis Diagnostics and Screening in the Era of Point-of-Care Laboratory Testing

Over the past ten years, standard diagnostics for cryptococcal meningitis in HIV-infected persons have evolved from culture to India ink to detection of cryptococcal antigen (CrAg), with the recent development and distribution of a point-of-care lateral flow assay. This assay is highly sensitive and specific in cerebrospinal fluid (CSF), but is also sensitive in the blood to detect CrAg prior to meningitis symptoms. CrAg screening of HIV-infected persons in the blood prior to development of fulminant meningitis and preemptive treatment for CrAg-positive persons are recommended by the World Health Organization and many national HIV guidelines. Thus, CrAg testing is occurring more widely, especially in resource-limited laboratory settings. CrAg titer predicts meningitis and death and could be used in the future to customize therapy according to burden of infection.

Fungal Diseases in the 21st Century: The Near and Far Horizons

Fungal diseases became a major medical problem in the second half of the 20th century when advances in modern medicine together with the HIV epidemic resulted in large numbers of individuals with impaired immunity. Fungal diseases are difficult to manage because they tend to be chronic, hard to diagnose, and difficult to eradicate with antifungal drugs. This essay considers the future of medical mycology in the 21st century, extrapolating from current trends. In the near horizon, the prevalence of fungal diseases is likely to increase, as there will be more hosts with impaired immunity and drug resistance will inevitably increase after selection by antifungal drug use. We can expect progress in the development of new drugs, diagnostics, vaccines, and immunotherapies. In the far horizon, humanity may face new fungal diseases in association with climate change. Some current associations between chronic diseases and fungal infections could lead to the establishment of fungi as causative agents, which will greatly enhance their medical importance. All trends suggest that the importance of fungal diseases will increase in the 21st century, and enhanced human preparedness for this scourge will require more research investment in this group of infectious diseases.

Diagnostic and therapeutic strategies in cryptococcosis: impact on outcome

Cryptococcosis diagnosis has been recently improved by the use of rapid cryptococcal antigen testing with lateral flow assays, which have proved sensitive and specific. Using "test and treat" screening strategies for cryptococcal disease with these tests has been showed effective in reducing cryptococcal meningitis (CM) in HIV-infected patients. Recommended induction, consolidation, and maintenance therapeutic strategy for CM is widely unavailable and/or expensive in low and middle-income settings. New therapeutic strategies, mostly using reduced duration, have recently shown acceptable outcome or are currently tested. Diagnostic and therapeutic guidelines for cryptococcal disease in limited resources countries are undergoing a paradigmatic shift.