CrAg Lateral Flow Assay Research Articles

Adjunctive Single-Dose Liposomal Amphotericin to Prevent Cryptococcal Meningitis in People With Human Immunodeficiency Virus (HIV)-Associated Cryptococcal Antigenemia and Low Plasma Cryptococcal Antigen (CrAg) Titers.

Cryptococcal meningitis is a leading cause of AIDS-related mortality. Cryptococcal antigen (CrAg) predicts the development of meningitis. Historically, despite standard- of-care fluconazole, 25%-30% of asymptomatic CrAg-positive persons develop breakthrough meningitis or death. We evaluated whether adding single high-dose liposomal amphotericin B to standard pre-emptive fluconazole therapy could improve meningitis-free survival. Participants with human immunodeficiency virus (HIV) and asymptomatic cryptococcal antigenemia in Uganda were randomized to liposomal amphotericin B (10 mg/kg once) with fluconazole or fluconazole alone through 24 weeks. We compared 24-week, meningitis-free survival time between treatment groups. After the second interim review, the Data Safety and Monitoring Board recommended no further enrollment of participants with low plasma CrAg lateral flow assay titers (≤1:80) due to futility. Herein, we present the results of participants with low plasma CrAg titers. 168 participants enrolled into the ACACIA trial had low plasma CrAg titers (≤1:80). During 24 weeks of follow-up, meningitis or death occurred in 14.5% (12/83) of participants randomized to liposomal amphotericin B with fluconazole versus 10.6% (9/85) assigned to fluconazole alone (hazard ratio, 1.42; 95% CI, .60-3.36; P = .431). Adverse events were more frequent in participants assigned to the intervention versus standard-of-care (28% vs 12%; P = .011). Among CrAg-positive persons with low titers (≤1:80), the addition of single-dose liposomal amphotericin B to fluconazole as pre-emptive therapy provided no additional clinical benefit. This trial provides supportive evidence that, in asymptomatic populations with low plasma CrAg titers, lumbar punctures are likely unnecessary as administration of meningitis treatment did not improve outcomes. Clinicaltrials.gov (NCT03945448).

Prevalence of Cryptococcal Antigenemia and Lateral Flow Assay Accuracy in Severely Immunosuppressed AIDS Patients.

This study aimed to estimate the prevalence of cryptococcal antigenemia detected by lateral flow assay (LFA) in AIDS patients and its accuracy in the diagnosis of cryptococcosis. Conducted at a university hospital in Brazil from March 2015 to July 2017, it included AIDS patients over 18 years old with a CD4+ count ≤ 200 cells/mm3. Cryptococcal antigen (CrAg) detection using LFA and latex agglutination (LA), along with blood and urine cultures, were performed. The reference standard was the identification of Cryptococcus spp. in clinical specimens through microbiological or histopathological examination. Among 230 patients, the prevalence of CrAg detected by LFA (CrAg LFA) was 13.0%. Factors associated with cryptococcal antigenemia included fever, vomiting, seizures, and a lack of antiretroviral therapy. The sensitivity and specificity of CrAg LFA were 83.9% and 98.0%, respectively. The positive predictive value (PPV) was 86.7%, the negative predictive value (NPV) was 97.5%, and overall accuracy was 96.1%. Cross-reactions were observed in patients with histoplasmosis and paracoccidioidmycosis, but not with aspergillosis or positive rheumatoid factor. The study concludes that the LFA is a useful tool for detecting cryptococcal antigenemia in severely immunocompromised AIDS patients due to its high NPV, specificity, and PPV.

Cryptococcosis in kidney transplant recipients: Current understanding and practices.

Cryptococcosis is the third most commonly occurring invasive fungal disease in solid organ transplant recipients (SOT). It is caused by encapsulated yeast, Cryptococcus species, predominantly Cryptococcus neoformans and Cryptococcus gattii. Though kidney transplant recipients are at the lowest risk of cryptococcosis when compared to other solid organ transplant recipients such as lung, liver or heart, still this opportunistic infection causes significant morbidity and mortality in this subset of patients. Mortality rates with cryptococcosis range from 10%-25%, while it can be as high as 50% in SOT recipients with central nervous system involvement. The main aim of diagnosis is to find out if there is any involvement of the central nervous system in disseminated disease or whether there is only localized pulmonary involvement as it has implications for both prognostication and treatment. Detection of cryptococcal antigen (CrAg) in cerebrospinal fluid or plasma is a highly recommended test as it is more sensitive and specific than India ink and fungal cultures. The CrAg lateral flow assay is the single point of care test that can rapidly detect cryptococcal polysaccharide capsule. Treatment of cryptococcosis is challenging in kidney transplant recipients. Apart from the reduction or optimization of immunosuppression, lipid formulations of amphotericin B are preferred as induction antifungal agents. Consolidation and maintenance are done with fluconazole; carefully monitoring its interactions with calcineurin inhibitors. This review further discusses in depth the evolving developments in the epidemiology, pathogenesis, diagnostic assays, and management approach of cryptococcosis in kidney transplant recipients.

High prevalence of central nervous system cryptococcosis using a fingerprick whole-blood lateral flow assay in individuals with neurological symptoms and advanced HIV disease in a Brazilian emergency department.

Timely diagnosis is key in managing central nervous system (CNS) cryptococcosis in people living with HIV/AIDS (PLWHA). There are few data on implementing fingerprick whole-blood cryptococcal antigen (CrAg) lateral flow assay (LFA) as the first test for diagnosing CNS cryptococcosis. We evaluated the prevalence of CNS cryptococcosis and cryptococcal antigenemia using fingerprick whole-blood in a referral emergency department (ED) in São Paulo, Brazil. This was a prospective cohort study of consecutive adult PLWHA with advanced HIV disease and neurological symptoms. Fingerprick whole-blood CrAg LFA was performed at bedside. Seventy-four individuals were enrolled (median age=40 years; males=62%). Prevalence of CNS cryptococcosis was 17.6% (13/74); 95% confidence interval (CI), 9.4-30.0%, and prevalence of positive fingerprick whole-blood CrAg LFA was 25.7% (19/74); 95% CI, 15.5-40.1%. Among the six (8.1%) patients with positive fingerprick whole-blood CrAg LFA and negative CSF CrAg LFA, four (5.4%) had isolated asymptomatic cryptococcal antigenemia, one (1.3%) had symptomatic cryptococcal antigenemia, and one (1.3%) had cryptococcemia. Prevalence of CNS cryptococcosis and cryptococcal antigenemia using fingerprick whole-blood CrAg LFA was high. Point-of-care testing was important for diagnosing CNS cryptococcosis in an ED from a middle-income country.

The incidence of histoplasmosis and cryptococcal antigenemia among patients attending a large HIV clinic in Trinidad

Our aim was to determine the incidence disseminated histoplasmosis and cryptococcal antigenemia among 280 patients with a CD4<350 cells/mm3 attending a large HIV clinic in Trinidad over the period November 2021-June 2022. Sera were screened for cryptococcal antigen (CrAg) using the Immy CrAg Immunoassay (EIA) and the Immy CrAg lateral flow assay (LFA). Urine was screened for Histoplasma antigen using the Immy EIA and the Optimum Imaging Diagnostics (OIDx) LFA. For the purposes of analysis, it was assumed, that all patients with positive urine Histoplasma antigen tests by both EIA and LFA and those with a single positive urine Histoplasma antigen test and clinical features of disseminated histoplasmosis were true positives. The incidence of probable disseminated histoplasmosis and cryptococcal antigenemia were 6.4% (18/280) and 2.5% (7/280) respectively. The sensitivity and specificity of the Immy Histoplasma EIA were 100% (95% CI, 81.5%-100%) and 98.5% (95% CI, 96.1% - 99.6%) respectively as compared to the OIDx Histoplasma LFA of 88.9% (95% CI, 65.3% - 98.6%) and 93.9% (95% CI, 90.3% - 96.5%) respectively, with substantial agreement between the 2 test kits (Kappa value = 0.763; 95% CI 0.685, 0.841). Testing for disseminated histoplasmosis in HIV patients is important in endemic areas.

False-negative cerebral spinal fluid cryptococcal antigen lateral flow assay due to postzone phenomenon in a patient with disseminated cryptococcal disease: a case report

This report presents the case of false-negative cerebral spinal fluid (CSF) cryptococcal antigen (CrAg) lateral flow assay (LFA) in a HIV-positive 25-year-old male. The patient presented with headache, nausea and vomiting for 5 days and syncope for 1 day. An initial CSF CrAg LFA test was negative, but a 1:4 dilution of the CSF was weakly positive and a 1:8 dilution was positive. A serum cryptococcal antigen test was weakly positive. Cultures of blood and CSF were all positive for Cryptococcus neoformans. The explanation for the false-negative CSF CrAg LFA test is that the antigen concentration was too high causing the postzone phenomenon.

A Possible New Diagnostic Method for Early Diagnosis of Cryptococcus Infection in Lymphoma Patient Co-Infected with SARS-CoV-2

A Cryptococcus subspecies, neoformans, represents the most pathogenic infection for humans, particularly in immunocompromised hosts (e.g., cancer patients, drug users). In the present study, we described a 67-year old woman with non-Hodgkin lymphoma who developed an infectious disease sustained by Cryptococcus neoformans. Biochemical data documented a decrease in lymphocytes count while clinical evaluation was suggestive on meningeal infection. The microbiological analysis of the serum, using a dilution pattern through the CrAg lateral flow assay (Immy, Norman, OK 73069, USA) detected the antigen of Cryptococcus (dilution 1/1280), and a treatment with liposomal amphotericin B (3 mg/kg id) plus flucytosine (100 mg/kg per day orally in four divided doses) were started, showing an improvement of symptoms. This case report suggests that an antigen dilution can be used to perform a rapid diagnosis and to quickly start the pharmacological treatment.

Digital Platform for Automatic Qualitative and Quantitative Reading of a Cryptococcal Antigen Point-of-Care Assay Leveraging Smartphones and Artificial Intelligence.

Cryptococcosis is a fungal infection that causes serious illness, particularly in immunocompromised individuals such as people living with HIV. Point of care tests (POCT) can help identify and diagnose patients with several advantages including rapid results and ease of use. The cryptococcal antigen (CrAg) lateral flow assay (LFA) has demonstrated excellent performance in diagnosing cryptococcosis, and it is particularly useful in resource-limited settings where laboratory-based tests may not be readily available. The use of artificial intelligence (AI) for the interpretation of rapid diagnostic tests can improve the accuracy and speed of test results, as well as reduce the cost and workload of healthcare professionals, reducing subjectivity associated with its interpretation. In this work, we analyze a smartphone-based digital system assisted by AI to automatically interpret CrAg LFA as well as to estimate the antigen concentration in the strip. The system showed excellent performance for predicting LFA qualitative interpretation with an area under the receiver operating characteristic curve of 0.997. On the other hand, its potential to predict antigen concentration based solely on a photograph of the LFA has also been demonstrated, finding a strong correlation between band intensity and antigen concentration, with a Pearson correlation coefficient of 0.953. The system, which is connected to a cloud web platform, allows for case identification, quality control, and real-time monitoring.

Cryptococcal antigen prevalence in HIV patients from a tertiary care centre in South India.

Cryptococcosis is an opportunistic mycosis, caused by Cryptococcus neoformans. Cryptococcal meningitis is one of the most fatal opportunistic infections associated with human immunodeficiency virus (HIV) infection. The aim of this study was to find the prevalence of cryptococcal antigenemia in people living with HIV (PLHA) and also to find the prevalence of opportunistic infections among these patients. A total of 204 non duplicate samples were collected from people with HIV aged above 18 years. Samples with CD4 count less than 300 were included in the study. Cryptococcal antigen detection was done by CrAg Lateral flow assay. None of the patients in our study were positive for cryptococcal antigen. Opportunistic infections were observed in 82 (40.2%) HIV positive patients. Candidiasis, tuberculosis and Pneumocystis jiroveci pneumonia were the most common opportunistic infections. This is the first study from the southern state of Kerala on the prevalence of Cryptococcal antigenemia among HIV positive individuals. The study showed that routine screening for cryptococcal antigen will not be cost effective in our population. Similar to other studies, eventhough candidiasis, tuberculosis and PCP were more commonly seen among people with CD4 count < 200 cells/mm3, there was no statistically significant association.

Investigation of CryptoPS LFA-positive sera in patients at risk of cryptococcosis.

Cryptococcal antigen (CrAg) is a capsule polysaccharide antigen that can be detected in the fluids of patients with cryptococcal infections. Cryptococcal Antigen Latex Agglutination System (CALAS), enzyme-linked immunosorbent assays (EIA), and lateral flow assay (LFA) are the main methods available. Two main commercial LFA kits are available: CryptoPS (Biosynex, Illkirch Graffenstaden, France) and CrAg LFA (IMMY, Inc. USA). In our lab, we prospectively used CryptoPS as a screening tool in serum for confirmed positive results with CALAS. We investigated the rigor of the CryptoPS test in serum in a multicentric evaluation over 3 years. To improve the specificity of CryptoPS in serum, we additionally implemented and evaluated a pretreatment protocol before CryptoPS testing. A total of 43 serum samples collected from 43 patients were investigated. We found that the CryptoPS assay is hampered by a high rate of false-positive results in serum with a high rate of CryptoPS-positive but CrAg LFA-negative and CALAS-negative sera in patients with no proof of Cryptococcus infection (n=29). Using a simple pretreatment procedure (5min incubation at 100°C and centrifugation) we were able to reverse false-positive results, suggesting that there could be interferent material present in the serum. Pretreatment also impacted the CryptoPS results (negative result) in two patients with the cryptococcal disease, one with isolated antigenemia and one with cryptococcal meningitis. Comparing the titers obtained with CALAS and CrAg LFA, we noticed that the titer obtained with CrAg LFA was almost 10-fold higher than those with CALAS. This study showed that Biosynex CryptoPS in serum could give false-positive results even in the absence of cryptococcal disease. These could be reduced by applying an easy pretreatment procedure to the serum before testing, with little but existing impact on the sensitivity.

P251 Disseminated Histoplasmosis in a Ghanaian HIV Patient: Role of Urine Histoplasma Antigen Testing in Rapid Diagnosis

Poster session 2, September 22, 2022, 12:30 PM - 1:30 PMBackgroundThe inhalation of the thermally dimorphic fungus Histoplasma capsulatum, may result in a wide spectrum of clinical manifestations, ranging from asymptomatic to acute or chronic pulmonary infection to disseminated infection. Symptomatic infections usually occur with high-level exposures or in immunocompromised patients mainly people with HIV. Despite the improved access to antiretroviral therapy, HIV-associated histoplasmosis remains a significant opportunistic infection in endemic regions including Africa. Unfortunately, histoplasmosis is rarely on the diagnostic radar of clinicians in several African countries such as Ghana due to insufficient awareness, inadequate epidemiological data, and poor fungal diagnostic capacity. Herein, we present a case of disseminated histoplasmosis in an HIV/AIDS patient in a tertiary hospital in Ghana.Case PresentationClinical history: A 43-year-old female was referred to the Dermatology Clinic of the Komfo Anokye Teaching Hospital (KATH) with symptoms of fever, cough, and anorexia. She had a history of a skin rash six weeks prior, which initially began on her face and later spread to the trunk and extremities. She was a known HIV/AIDS patient on anti-retroviral drugs (EFV, TFV, 3TC) with no other chronic conditions. She was anemic with a previous hemoglobin level of 7.6 g/dl. Initial diagnostic workup for cutaneous bacterial or viral infection detected no abnormality.ExaminationShe was semi-conscious, and her nostrils were clogged with crust. The patient appeared pale, warm, and anicteric. The face, trunk, and extremities (including palms) were covered with mucocutaneous erosions, ulcers, multiple papule plaques, and nodules. Examination of the cervix revealed the presence of lymph nodes.InvestigationsA fungal diagnostic work-up was done to rule out cutaneous or disseminated mycosis particularly cryptococcosis which was previously captured as a differential diagnosis. Serum cryptococcal antigen lateral flow assay (LFA) (CrAg LFA, IMMY) and Aspergillus galactomannan (GM) (sona Aspergillus GM LFA, IMMY) tests were both negative, but urine Histoplasma GM enzyme immunoassay (EIA) (clarus Histoplasma GM EIA, IMMY) test was positive with a very high optical density indicating high fungal burden was reported. A skin biopsy was also sent for histopathology and fungal culture. Histopathology analysis revealed the presence of yeast cells with round central nuclei and cytoplasmic clearing. Special staining with Periodic acid–Schiff (PAS) confirmed the presence of yeast cells, suggestive of histoplasmosis. Fungal culture was however negative after 8 weeks of incubation. A diagnosis of disseminated histoplasmosis was made.Treatment and outcomeThe patient was administered 200 mg bid of itraconazole. Few weeks after treatment, most of her skin lesions and ulcers were healed. The patient was discharged on itraconazole after the disappearance of some of her lesions. Few weeks later, the patient was admitted but died due to complications of anemia.ConclusionDisseminated histoplasmosis in HIV may be a relatively common but largely unrecognized condition in Ghana. This case report highlights the need to improve awareness of histoplasmosis among clinicians in Ghana and enhance laboratory capacity to provide timely simple contemporary fungal tests for rapid diagnosis and prompt initiation of effective antifungal agents.

S2.2d Evaluation of new tools for the diagnosis of histoplasmosis

S2.2 Histoplasmosis and talaromycosis, September 21, 2022, 3:00 PM - 4:30 PMIn sub-Saharan Africa (SSA) and West African countries, histoplasmosis is rarely diagnosed probably due to lack of epidemiological information, insufficient training and awareness of frontline healthcare workers, and clinical features very similar to those of tuberculosis that can be misleading. This fungal infection mainly affects immunocompromised patients and particularly advanced HIV patients, with a high case-fatality rate in the absence of treatment (from <10% to >40%). The classical diagnostic methods are microscopic observation of yeasts with suggestive morphology and a positive culture from a biological sample. However, direct examination requires regular practice, and the yeasts can be confused with other pathogens and culture takes prolonged incubation (often 2-6 weeks) and involves, when positive, handling in a level 3 security laboratory.Implementing non-invasive diagnostic tools will allow us to improve histoplasmosis diagnosis for the most exposed patients and also to evaluate the prevalence of this fungal infection in countries where data are still lacking. Rapid diagnostic tests (RDTs) such as the TB Lam for the diagnosis of tuberculosis or the Cryptococcal antigen (CrAg) lateral flow assay (LFA) for cryptococcosis have demonstrated their usefulness for the management of advanced HIV patients in similar contexts.Recently, two RDTs have been made commercially available for the diagnosis of histoplasmosis, based on urinary monoclonal antigen detection: (1) Histoplasma Capsulatum Urinary Antigen Rapid Test from Optimium Imaging Diagnostics (OIDx) and (2) Histoplasma Urine Antigen Lateral Flow Assay from MiraVista Diagnostics (MV).Objectives and MethodsOur objective was to evaluate these new tools, by experimenting with their feasibility in low-and middle-income countries (LMICs) and by studying their diagnostic performances using different sample collections recovered from patients with disseminated histoplasmosis (culture proven), other HIV-related infections, and proven negative urines (culture and other Histoplasma antigen detections).ResultsPreliminary results were obtained using the EDIRAPHIS study frozen samples from hospitalized patients diagnosed with proven positive and negative histoplasmosis from French Guiana and Suriname (n = 43) tested with OIDx and MV tests. We calculated a Se = 74.2% and a Sp = 83.3% for OIDx and a Se = 77.4% and a Sp = 91,7% for MV. A low number of false positives for both tests, <17% for OIDx and <9% for MV were observed. We have a perfect correlation between the observers with a Kappa coefficient of 100% for both tests. Overall, the probabilities that the patient had histoplasmosis with a positive test were 92% and 96% for OIDx and MV respectively.ConclusionThese first results are very promising and will be completed with two other specimen collections to increase the total numbers of our sampling and get a whole picture of the performances of these two RDTs. The next step will be to implement these new tools at the bedside or in laboratories together with other tests in different settings across SSA.Diffusion of RDTs together with appropriate training of clinical and laboratory teams and accessibility to treatment may help reduce the burden of histoplasmosis in endemic areas of SSA where the prevalence of the advanced-HIV disease is high.

P449 Semi-quantitative cryptococcal antigen rapid test (CryptoPS, Biosynex®) for cryptococcal meningitis in patients living with HIV in Sub-Saharan Africa: prospective multicenter diagnostic accuracy study (DREAMM)

Poster session 3, September 23, 2022, 12:30 PM - 1:30 PMBackgroundCryptococcal meningitis (CM) remains a leading cause of HIV-related meningoencephalitis in African low- and middle-income countries (LMICs), causing 15%-20% of HIV-related deaths. Rapid Diagnostic Tests (RDTs) are powerful tools and key to speeding-up the diagnosis at the bedside, allowing for rapid and targeted treatment, especially in LMICs. For the past 10 years, Cryptococcal Antigen (CrAg) RDTs have a major role in CM management.Driving Reduced AIDS Meningo-Encephalitis Mortality (DREAMM) was a multicenter implementation science study and a capacity-building project to reduce the mortality of HIV-related central nervous system infections (CNS). One of the main DREAMM approaches was to improve the diagnosis of CNS infections at the bedside and in parallel in local laboratories. Within DREAMM, HIV-infected, adult people living with HIV (>18 years old) with suspected CNS infections were recruited in five hospital sites in Cameroon, Malawi, and Tanzania.ObjectivesOur objective was to evaluate the implementation of CrAg CryptoPS (Biosynex, Illkirch Graffenstaden, France), a new semi-quantitative RDT, in routine care settings in Sub-Saharan Africa.MethodsAll CrAg CryptoPS performed were compared to the reference CrAg lateral flow assay (Immy®). The evaluation was done by the local research teams in four DREAMM laboratories sites. CrAg CryptoPS's implementation was evaluated in 301 plasma samples and 258 cerebrospinal fluid (CSF) samples from 320 participants (patients diagnosed with cerebral toxoplasmosis did not have a lumbar puncture). In this analysis, the results will be considered in a binary way (positive/negative).ResultsBetween January 2018 and March 2021, 356 participants were prospectively enrolled with suspected HIV-related CNS infections, including CM, tuberculous meningitis, cerebral toxoplasmosis, and bacterial meningitis cases. Cryptococcal meningitis was the leading cause of CNS infections in Malawi and Tanzania with 66.3% (53/80) and 59.6% (59/99) cases respectively, and the second cause in Cameroon with 40.0% (39/90) cases after cerebral toxoplasmosis.In plasma, CryptoPS's sensitivity was 99.23% (95% CI, 0.98-1.01) and specificity was 94.15% (95% CI, 0.91-0.98); positive and negative predictive values were 92.8% and 99.4%, respectively. In CSF, the sensitivity and specificity of CryptoPS were 100% (95% CI, 0.0-0.0), and 99.26% (95% CI, 0.98-1.01), respectively; positive and negative predictive values were both 100%. A low number of false-positives were observed (<4% in plasma and <0.5% in CSF).ConclusionCryptoPS was evaluated in a context of hospitalized patients within a project including all causes of HIV-related CNS infection, not only CM. The sensitivity and specificity of CryptoPS calculated in these preliminary results are promising. Semi-quantitative CryptoPS has the potential to be used to tailor antifungal therapy but further optimizations need to be done prior to large-scale implementation in African LMICs. In addition, future work to determine CrAg antigen titres is planned, in the perspective to optimize treatment of CrAg positive cases who decline lumbar puncture.

Epidemiology and Mortality of Cryptococcal Disease in Guatemala: Two-Year Results of a Cryptococcal Antigen Screening Program.

Cryptococcal disease is an important opportunistic infection among people living with HIV. The cryptococcal antigen (CrAg) can be detected before the clinical onset of meningitis and its screening is recommended. Here, we evaluated CrAg frequency, and describe the epidemiological characteristics and mortality at 180 days in a cohort of HIV patients from Guatemala. A total of 3457 patients were screened with a CrAg lateral flow assay in serum between January 2017 and December 2018. CrAg positivity was 11.5% in patients with ≤100 CD4/mm3, 8.7% in patients with <200 CD4/mm3, and 6.3% in patients with <350 CD4/mm3. In Latin America, we estimated 9.2% CrAg positivity (IC95% 7.9–10.7%) in patients with ≤100 CD4/mm3. Among patients newly diagnosed with HIV, we estimated 4416 incident cases per year in Latin America in those with <200 CD4/mm3 and 5289 in those with <350 CD4/mm3. In addition, we calculated the burden in people not on ARV or without viral suppression and found 28,672 cases. CrAg screening should be considered in patients who have a CD4 cell count < 350 cells/mm3. Cryptococcal meningitis was associated with 30.8% mortality in Guatemala. Global access to diagnosis as well as to liposomal amphotericin B and flucytosine is a priority.

Cryptococcal and Histoplasma Antigen Screening Among People With Human Immunodeficiency Virus in Ghana and Comparative Analysis of OIDx Histoplasma Lateral Flow Assay and IMMY Histoplasma Enzyme Immunoassay.

BackgroundCryptococcal meningitis (CM) and disseminated histoplasmosis (DH) are common in people with human immunodeficiency virus (PWH) and diagnosed by detecting cryptococcal antigen (CrAg) and Histoplasma antigen (HistoAg), respectively. In Ghana, CM and DH are rarely suspected by clinicians due to limited epidemiological data.MethodsThis 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 HistoAg, 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 Optimum Imaging Diagnostics (OIDx) Histoplasma LFA. Laboratory investigations were conducted by the research team, and 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.ResultsOverall, 150 participants were recruited. There were 73% (n = 109) females, and the age range was 18–62 years. The prevalence rates of CrAg and HistoAg were 2.7% (4 of 150) and 4.7% (5 of 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 5 patients and follow-up revealed 2 deaths and 3 recoveries.ConclusionsHistoplasmosis 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.

Etiology of meningitis among adults in three quaternary hospitals in Mozambique, 2016-2017: The role of HIV.

BackgroundMeningitis remains an important cause of morbi-mortality in adults in sub-Saharan Africa. Data on the etiological investigation of meningitis in adults in Mozambique is limited and most studies were conducted in southern Mozambique. Identification of the etiology of meningitis in adults are crucial to guide prevention and treatments strategies. In this study, we determine the burden of fungal and bacterial meningitis among adults at the three largest hospitals in Mozambique.MethodWe performed analysis of data from the routine sentinel surveillance system for meningitis in Mozambique from January 2016 to December 2017. Cerebrospinal fluid (CSF) samples were collected from eligible adults (≥18 years old) who met World Health Organization (WHO) case definition criteria for Meningitis. All samples were tested by cryptococcal antigen (CrAg) lateral flow assay (LFA), culture and triplex real-time polymerase chain reaction (qPCR) assay and all patients were tested for human immunodeficiency virus (HIV) using the national algorithm for HIV testing.ResultsRetrospective analysis of 1501 CSF samples from adults clinically suspected of meningitis revealed that 10.5% (158/1501) were positive for bacterial and fungal meningitis. Of these 158 confirmed cases, the proportion of Cryptococcal meningitis and pneumococcal meningitis was38.6% (95% CI: 31.0% to 46.7%) and 36.7% (95% CI: 29.2% to 44.7%), respectively. The other bacterial agents of meningitis identified include Neisseria meningitidis (8.9%; 14/158), Escherichia coli (6.3%; 10/158), Haemophilus influenzae (5.1%; 8/158) and S. aureus (4.4%; 7/158), which represent (24.7%; 39/158) of the total confirmed cases.ConclusionAltogether, our findings show a high burden of Cryptococcal meningitis among adults in Mozambique, especially in people living with HIV, followed by pneumococcal meningitis. Our findings suggest that rollout of CrAg Lateral Flow Assay in the health system in Mozambique for early detection of cryptococcus neoformans is necessary to improve overall patient care.

Evaluation of a Cryptococcus capsular polysaccharide detection FungiXpert LFA (lateral flow assay) for the rapid diagnosis of Cryptococcosis.

The FungiXpert LFA was developed to diagnose fungal meningitis caused by Cryptococcus yeasts, by using serum or cerebrospinal fluid. It was compared to an existing lateral flow assay (LFA). The FungiXpert LFA performed well in qualitative and semi-quantitative tests.

Evaluation of the Diagnostic Performance of a Semiquantitative Cryptococcal Antigen Point-of-Care Assay among HIV-Infected Persons with Cryptococcal Meningitis.

A newly developed cryptococcal antigen (CrAg) semiquantitative (SQ) lateral flow assay (LFA) provides a semiquantitative result in a rapid one-step test instead of performing serial dilutions to determine CrAg titer. We prospectively compared the diagnostic performance of the CrAgSQ assay (IMMY) with the CrAg LFA (IMMY) on cerebrospinal fluid (CSF) samples collected from persons with HIV-associated meningitis. The CrAgSQ grades (1+ to 5+) were compared with CrAg LFA titers and quantitative CSF fungal cultures. Among 87 participants screened for HIV-associated meningitis, 60 had cryptococcal meningitis (59 CrAg positive [CrAg+] by LFA and 1 false negative due to prozone with CrAg LFA titer of 1:1,310,000 and culture positivity), and 27 had no cryptococcal meningitis by CrAg LFA or culture. The CrAgSQ on CSF had 100% (60/60) sensitivity and 100% specificity (27/27). CSF CrAg titers ranged from 1:5 to 1:42 million. CrAgSQ grades of 1+, 2+, 3+, 4+, and 5+ corresponded to median CrAg LFA titers of 1:<10, 1:60, 1:7,680, 1:81,920, and 1:1,474,000, respectively. CSF CrAgSQ grades 3+ or higher were always CSF culture positive. Mortality at 14 days for those with low CrAgSQ grade (1+ to 3+) was 5% (1/22) versus 21% (8/38) with high CrAgSQ grades (4+ to 5+) (P = 0.084). The CrAgSQ demonstrates excellent diagnostic performance, maintaining both the sensitivity and specificity of the CrAg LFA, and counters false-negative prozone effects. The CrAgSQ assay reading is more complex but does provide useful clinical information about disease burden and probability of culture positivity in a single rapid diagnostic test.

High prevalence of Cryptococcal antigenemia using a finger-prick lateral flow assay in individuals with advanced HIV disease in Santarém Municipality, Brazilian Amazon Basin.

There is scarce information about HIV-related cryptococcosis in the Brazilian Amazon basin where laboratory infrastructure is limited. The serum cryptococcal antigen (CrAg) lateral flow assay (LFA) has simplified diagnosis of cryptococcosis and is recommended for screening in advanced HIV disease. We evaluated the prevalence of cryptococcal antigenemia using finger-prick CrAg LFA in the Brazilian Amazon basin. We enrolled a prospective cohort of outpatients and hospitalized individuals with advanced HIV disease at two centers in Santarém Municipality, Northern Brazil. All individuals were>18 years old with advanced HIV disease, regardless of antiretroviral therapy (ART) status and with no prior or current history of confirmed cryptococcal meningitis. We tested CrAg LFA on finger-prick whole blood using an exact volume transfer pipette. From August 2018 to October 2019, 104 individuals were enrolled (outpatients 62 [60%] and hospitalized 42 [40%]). Median age was 38 years (interquartile range [IQR] 30-46), and 84 (81%) were male. Sixty-five (63%) individuals were ART-naïve. Prevalence of finger-prick CrAg LFA-positive was 10.6%; 95% CI, 5.4 to 18.1%. Prevalence of finger-prick CrAg LFA-positive among individuals without neurological symptoms was 6.0%; 95% CI, 1.7-14.6%. The number needed to test to detect one CrAg-positive individual was 9.4 persons (95% CI, 5.5-18.5). Prevalence of cryptococcal antigenemia using finger-prick whole blood CrAg LFA was high. Point-of-care approach was important for the diagnosis and screening of cryptococcosis in resource-limited settings. Screening and preemptive therapy strategy should be urgently implemented in individuals with advanced HIV disease in the Brazilian Amazon basin.

Evaluation of a Cryptococcal Antigen Lateral Flow Assay and Cryptococcal Antigen Positivity at a Large Public Hospital in Atlanta, Georgia.

Background Cryptococcus neoformans is a major cause of morbidity and mortality among human immunodeficiency virus (HIV)-infected persons worldwide, and there are scarce recent data on cryptococcal antigen (CrAg) positivity in the United States We sought to determine the frequency of cryptococcal disease and compare the performance of a CrAg lateral flow assay (LFA) versus latex agglutination (LA) test.MethodsAll patients from Grady Health System in Atlanta who had a serum or cerebrospinal fluid (CSF) sample sent for CrAg testing as part of clinical care from November 2017 to July 2018 were included. Percentage positivity and test agreement were calculated.ResultsAmong 467 patients, 557 diagnostic tests were performed; 413 on serum and 144 on CSF. The mean age was 44 years, and most were male (69%) and had HIV (79%). Twenty-four (6.4%, 95% confidence interval [CI] = 4.1–9.4) patients were serum CrAg positive, and 8 (5.8%, 95% CI = 2.6–11.2) individuals tested positive for CSF CrAg. Although overall agreement between the LA and LFA was substantial to high for CSF (κ = 0.71, 95% CI = 0.51–0.91) and serum (κ = 0.93, 95% CI = 0.86–1.00), respectively, there were important discrepancies. Five patients had false-positive CSF LA tests that affected clinical care, and 4 patients had discordant serum tests.ConclusionsWe found a moderately high proportion of cryptococcal disease and important discrepancies between the LA test and LFA. Clinical implications of these findings include accurate detection of serum CrAg and averting unnecessary treatment of meningitis with costly medications associated with high rates of adverse events.