Cryptococcal Latex Agglutination Test Research Articles

Assessment of an Antigen Lateral Flow Assay (LFA) For Point of Care Diagnosis of Cryptococcosis in Senegal

Background: Cryptococcal meningitis is a medical emergency. Therefore, simple, rapid and efficient diagnostic techniques are needed. New rapid diagnostic tests based on the detection of cryptococcal antigen have been developed. The aim of our study was to evaluate the performance of the Dynamiker Cryptococcal Antigen Lateral Flow Assay (LFA) in our routine diagnosis activities. Materials and Methods: We performed a prospective study from November 2017 to August 2018 at the ParasitologyMycology laboratory of the CHNU of Fann in Dakar. Biological samples collected from HIV-infected patients hospitalized at the infectious diseases department of CHUN de Fann were used. Serum, CSF and urine samples received in the laboratory were examined using mycological techniques and the cryptococcal latex agglutination test (CLAT). The performance of the Dynamiker test was evaluated considering CLAT as the reference method. Results: A total of 39 samples were examined: 14 CSF, 24 sera and 1 urine sample. The average age was 44.5 years with a predominance of female patients (64.1%). The mean CD4 count was 73 cells/mm3 . Among the 39 samples tested, 23.1% were CLAT positive while 30.8% were LFA positive. The sensitivity and specificity rates were 100% and 75% respectively. The percentage of correlation between the two methods was 92.3%. The intensity of the bands on the LFA was high en 66.7% of cases. Conclusion: The excellent sensitivity of the rapid Cryptococcal Antigen Lateral Flow Assay and the rapidity of obtaining results (less than 15 minutes) make it suitable for routine diagnosis of cryptococcal meningitis.

Prevalence of cryptococcal antigenemia in hospitalized patients with liver cirrhosis.

The benefits of screening for cryptococcal antigenemia and of preemptive antifungal treatment in HIV-infected patients have been proven. Liver cirrhosis is an important risk factor for cryptococcal infections. Cryptococcal infections are rapidly fatal in patients with liver cirrhosis, especially when diagnosis is delayed. However, screening for cryptococcal antigenemia has not been investigated in these patients. The aim of this study was to investigate the prevalence of cryptococcal antigenemia in hospitalized patients with liver cirrhosis. This prospective study was conducted at Seoul National University Hospital from July 2017 to January 2018. We included patients with liver cirrhosis who were admitted regardless of symptoms or signs suggesting cryptococcal infections. The severity of cirrhosis was evaluated from Child-Pugh and model for end-stage liver disease (MELD) scores. Serum cryptococcal antigenemia was determined using a latex agglutination test. A total of 294 patients were included in the analysis, comprising 104 (35.4%), 100 (34.0%), and 90 (30.6%) patients in Child-Pugh classes A, B, and C, respectively. There were 21 cases of spontaneous bacterial peritonitis, and 14 of hepatic encephalopathy, but none of cryptococcal peritonitis or meningitis. In addition, none of the patient specimens tested positive in the serum cryptococcal latex agglutination test (one-sided 97.5% confidence interval, 0% ∼ 1.2%). Liver cirrhosis is a major risk factor for cryptococcal infections, but the prevalence of serum cryptococcal antigen positivity in patients with liver cirrhosis is very low. Therefore, screening for cryptococcal antigenemia and preemptive antifungal treatment in cirrhotic patients might not be beneficial.

Disseminated cryptococcosis with recurrent multiple abscesses in an immunocompetent patient: a case report and literature review

BackgroundCryptococcus neoformans is frequently present as an opportunistic pathogen mainly affecting immunocompromised populations. Disseminated C. neoformans infection in immunocompetent population is rare and usually involves lung and central nerve system. Cryptococcus from biologic samples can easily grow on routine fungal and bacterial culture media. Besides, cryptococcal latex agglutination test has been established as a reliable diagnostic tool with overall sensitivities of 93–100%.Case presentationWe report a rare disseminated cryptococcosis case which presented with chronic recurrent multiple abscess in an immunocompetent male involving skin, lung, spine and iliac fossa without evidence of central nerve system involving. The results of serum cryptococcal latex agglutination tests and standard microbial cultures were negative. The patient underwent empirical anti-bacterial and anti-tuberculosis therapy which turned out to be effectless. Finally, bedside inoculation of the pus was carried out and revealed Cryptococcus neoformans, which was confirmed by polymerase chain reaction. After the administration of anti-fungal drugs including liposomal amphotericin B, the patient recovered from fever and paraplegia.ConclusionsThis case reveals an uncommon pattern of disseminated C. neoformans infection in immunocompetent population presented with chronic multiple abscess and without central nerve system involving. Negative routine microbial cultures may not necessarily rule out cryptococcosis, especially in early stage. Besides, cryptococcal latex agglutination test does have a chance of false negative, which might be related with “capsule-deficiency”. Moreover, this phenomenon could be related with low-grade virulence and relative long illness duration.

Prevalence of Disseminated Cryptococcosis among Human Immunodeficiency Virus Infected Patients in Benin City, Nigeria

Aim: To determine the prevalence of disseminated cryptococcosis among symptomatic HIVinfected patients, attending the Antiretroviral Treatment Clinic at the University of Benin Teaching Hospital, Benin City, Nigeria. Study Design: Cross-sectional study. Place and Duration of Study: Department of Internal Medicine and Department of Medical Microbiology, University of Benin Teaching Hospital, Edo State, Nigeria, between September 2010 Original Research Article Joseph et al.; BJMMR, 6(7): 715-722, 2015; Article no.BJMMR.2015.248 716 and August 2011. Methodology: Five hundred consecutive symptomatic HIV-infected patients, on ART were enrolled into this cross-sectional study (266 males, 234 females, age range 18-81 years, mean age, 40.08 years). A blood sample collected from each participant was screened for serum cryptococcal antigen (CRAG) using the cryptococcal Latex agglutination test. The viral load and CD4+ T -cell count were also determined in parallel. A structured questionnaire was used to gather Information on socio demographic characteristics, medical and treatment history of participants. Data collected and the results of laboratory tests were analyzed using the SPSS software, version 22.0. Results: The prevalence of serum cryptococcal antigen was 9.8%. Majority (66.8%) of the participants had a CD4+ T-cell count of less than 100 cells/μl. The association between serum CRAG and CD4+ T-cell was found to be significant (P < .001). Viral load done for only 90 of the participants was high in 51.1%. The association between serum CRAG and viral load was found to be significant (P < .001). Conclusion: The prevalence of serum CRAG was high among symptomatic HIVinfected patients on ART, in Benin city, Nigeria, despite ART implementation. There is need therefore for a routine cryptococcal antigen test for all symptomatic HIV-infected patients on ART, while further microbiological investigations for those with positive result are recommended for appropriate medical intervention.

Profile and mortality outcome of patients admitted with cryptococcal meningitis to an urban district hospital in KwaZulu-Natal, South Africa.

IntroductionCryptococcal meningitis (CCM) is one of the leading causes of early mortality among HIV-infected patients. This study was a part of clinical audit [1] aimed at improving care for patients with CCM at an urban district hospital in South Africa.MethodsClinical records of all patients (age>13 years) admitted to the hospital with a diagnosis of CCM (based on a positive India ink, positive cryptococcal latex agglutination test (CLAT) or a positive culture of Cryptococcus neoformans) between June 2011 and December 2012 were retrospectively reviewed. Descriptive statistics and Chi-square analysis were generated with Epi Info 7.1.2.0. 95% confidence intervals were reported where appropriate.ResultsOf the 127 patients admitted with CCM, only 97 (76.4%) knew their HIV status. Only 44.8% (43/96) of those who knew they were HIV positive were on antiretroviral therapy (ART). Seventeen out of 25 patients (68%) previously treated for CCM had defaulted fluconazole and only 60% (15/25) were on ART. Acute mortality (death within 14 days of CCM diagnosis) was 55.9% (71/127). The median time to death from diagnosis was four days (IQR 2–9). The association between CSF WBC count<20cells/mL and increased risk of death within 14 days was statistically significant (OR 2.2; 95% CI 1.1–4.6, p=0.03). Patients with heavy cryptococcal burden (reported as numerous yeasts seen on microscopy) at diagnosis were three times more likely to die within 14 days of diagnosis of CCM (OR 3.2; 95% CI 0.9–10.7, p=0.06). Even though a CD4 count<100cells/mm3 was associated with a 1.6 times increased acute mortality risk, the association was not statistically significant (OR 1.6; 95% CI 0.6–4.6, p=0.3). The role of elevated CSF opening pressure at diagnosis was not assessed because only two (1.6%) patients had their baseline opening pressure measured.ConclusionsAcute CCM-related mortality remains high. The number of patients who do not know their HIV status, the number of HIV positive patients not on ART, the high level of non-adherence to fluconazole and the proportion of patients not on ART after at least one previous CCM episode all point to the need of developing comprehensive strategies aimed at encouraging HIV testing and improving patient's retention in HIV care and support.

Comparative Utility of Cytokine Levels and Quantitative RD-1-Specific T Cell Responses for Rapid Immunodiagnosis of Tuberculous Meningitis

The rapid diagnosis of tuberculous meningitis (TBM) is problematic. We found in 150 patients with suspected TBM that, similar to RD-1-specific quantitative cerebrospinal fluid (CSF) T-cell responses, unstimulated CSF gamma interferon (IFN-γ) levels when used together with other rapid confirmatory tests (Gram stain and cryptococcal latex agglutination test) may allow the accurate and rapid diagnosis of TBM in a setting in which tuberculosis (TB) and HIV are endemic. In resource-poor settings, a clinical prediction rule (CPR) may be useful to clinicians, and thus the IFN-γ assay may potentially need to be used only when the clinical score is below a prespecified threshold. These preliminary findings will need to be confirmed in further studies.

Cerebrospinal T-Cell Responses Aid in the Diagnosis of Tuberculous Meningitis in a Human Immunodeficiency Virus– and Tuberculosis-Endemic Population

Current tools for the rapid diagnosis of tuberculous meningitis (TBM) are suboptimal. We evaluated the clinical utility of a quantitative RD-1 IFN-gamma T-cell enzyme-linked immunospot (ELISPOT) assay (T-SPOT.TB), using cerebrospinal fluid cells for the rapid immunodiagnosis of TBM. To evaluate the diagnostic utility of the RD1 antigen- specific ELISPOT assay for the diagnosis of tuberculous meningitis. The ELISPOT assay was evaluated in 150 patients with suspected TBM who were categorized as definite-TBM, probable-TBM, and non-TBM. Culture or polymerase chain reaction positivity for Mycobacerium tuberculosis served as the reference standard. To determine the diagnostic value of the ELISPOT assay, a clinical prediction rule was derived from baseline clinical and laboratory parameters using a multivariable regression model. A total of 140 patients (81% HIV-infected; median CD4 count, 160 cells/mm(3)) were included in the final analysis. When comparing the definite-TBM (n = 38) and non-TBM groups (n = 48), the ELISPOT assay (cut point of > or =228 spot-forming cells per 1 million mononuclear cells) was a useful rule-in test: sensitivity 58% (95% confidence interval [CI], 41-74); specificity 94% (95% CI, 83-99). However, ELISPOT outcomes improved when other rapid tests were concurrently used to exclude bacterial (Gram stain) and cryptococcal meningitis (latex-agglutination test) within the non-TBM group. Using this approach, the ELISPOT assay (cut point of > or =46 spot-forming cells) was an excellent rule-in test: sensitivity 82% (95% CI, 66-92); specificity 100% (95% CI, 78-100); positive predictive value, 100% (95% CI, 89-100); negative predictive value, 68% (95% CI, 45-86); area under the curve, 0.90. The ELISPOT assay had incremental diagnostic value compared with the clinical prediction rule. The RD-1 ELISPOT assay, using cerebrospinal fluid mononuclear cells and in conjunction with other rapid confirmatory tests (Gram stain and cryptococcal latex-agglutination test), is an accurate rapid rule-in test for TBM in a TB and HIV endemic setting.

Population-based surveillance for cryptococcosis in an antiretroviral-naive South African province with a high HIV seroprevalence

To measure the burden of disease and describe the epidemiology of cryptococcosis in Gauteng Province, South Africa. The study was an active, prospective, laboratory-based, population-based surveillance. An incident case of cryptococcosis was defined as the first isolation by culture of any Cryptococcus species from any clinical specimen, a positive India ink cryptococcal latex agglutination test or a positive histopathology specimen from a Gauteng resident. Cases were identified prospectively at all laboratories in Gauteng. Case report forms were completed using medical record review and patient interview where possible. Between 1 March 2002 and 29 February 2004, 2753 incident cases were identified. The overall incidence rate was 15.6/100 000. Among HIV-infected persons, the rate was 95/100 000, and among persons living with AIDS 14/1000. Males and children under 15 years accounted for 49 and 0.9% of cases, respectively. The median age was 34 years (range, 1 month-74 years). Almost all cases (97%) presented with meningitis. Antifungal therapy was given to 2460 (89%) cases of which 72% received fluconazole only. In-hospital mortality was 27% (749 cases). Recurrences occurred in 263 (9.5%) incident cases. Factors associated with death included altered mental status, coma or wasting; factors associated with survival included employment in the mining industry, visual changes or headache on presentation. This study demonstrates the high disease burden due to cryptococcosis in an antiretroviral-naive South African population and emphasizes the need to improve early recognition, diagnosis and treatment of the condition.

Collaborative evaluation of antigen detection by a commercial latex agglutination test and enzyme immunoassay in the diagnosis of invasive candidiasis

The Cand-Tec Candida detection system and enzyme immunoassay for serum mannan were retrospectively compared in a controlled collaborative evaluation of antigen detection in 32 patients with candidiasis proven by biopsy or culture from a normally sterile site and with sera drawn within 7 days of inclusion. With a threshold titer of 1/8, which excluded false-positive results in 17 hospitalized patients without candidiasis, sensitivities for all 32 patients with candidiasis were 44% for the Cand-Tec assay and 17% for the enzyme immunoassay. Both assays provided greater sensitivity when sera were drawn within 24 h of inclusion in the study and in the category of patients with invasive candidiasis (57% by Cand-Tec and 33% by enzyme immunoassay). The Cand-Tec assay gave false-positive results (titer, greater than or equal to 1/8) in 4 of 6 patients with transient candidemia, in 1 of 20 otherwise healthy patients with rheumatoid factor, and in 1 patient with a positive cryptococcal latex agglutination test. Three serum specimens from 3 of 32 patients with candidiasis contained rheumatoid factor and gave titers of greater than or equal to 1/8 by the Cand-Tec assay. Detection of serum mannan by enzyme immunoassay was less sensitive but more specific than the Cand-Tec Candida detection system for the diagnosis of invasive candidiasis.

VALUE OF LATEX TEST IN CRYPTOCOCCAL MENINGITIS

The history of a man suffering from chronic cryptococcal meningitis is presented. A series of cerebrospinal fluid and serum specimens from this patient were investigated retrospectively by latex agglutination for the presence of cryptococcal antigens. The results were related to other laboratory findings, and to the patient's clinical progress. The cryptococcal latex agglutination test was shown to be potentially useful in the diagnosis, management, and prognosis of such patients.