6 research outputs found
Additional file 1: of Evaluation of trypan blue stain in a haemocytometer for rapid detection of cerebrospinal fluid sterility in HIV patients with cryptococcal meningitis
Study raw data. File contains a full set of raw data for the tests performed and baseline clinical and demographics characteristics. (XLSX 570 kb
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Evaluation of the BioFire® FilmArray® Meningitis/Encephalitis panel in an adult and pediatric Ugandan population
Background
Meningitis causes significant mortality in sub-Saharan Africa and limited diagnostics exist. We evaluated the utility of the BioFire® FilmArray® Meningitis/Encephalitis multiplex PCR panel (BioFire ME) in HIV-infected adults and HIV-infected and uninfected children presenting with suspected meningitis in Uganda.
Methods
We tested cerebrospinal fluid (CSF) using a stepwise meningitis diagnostic algorithm including BioFire ME. We determined the diagnostic performance of BioFire ME for cryptococcal meningitis, using cryptococcal antigen (CrAg) and CSF culture as reference standards, and assessed other central nervous system (CNS) pathogens identified by the panel.
Results
We evaluated 328 adult and 42 pediatric CSF specimens using BioFire ME. Of the adult CSF samples tested, 258 were obtained at baseline, and 70 were obtained from repeat lumbar punctures in cryptococcal meningitis. For Cryptococcus, sensitivity was 82%, specificity was 98%, PPV was 98%, and NPV was 79% in baseline specimens using CSF CrAg as the reference standard. Among follow-up specimens, a negative BioFire ME for Cryptococcus predicted CSF culture sterility with 84% NPV. Overall sensitivity was decreased at low fungal burdens: 29% for 0–99 Cryptococcus CFU/mL compared to 94% for ≥100 CFU/mL in baseline specimens. Other pathogens detected included E. Coli, H. influenzae, S. pneumoniae, CMV, enterovirus, HSV, HHV-6, and VZV. Two specimens tested positive for S. pneumoniae and one for Cryptococcus in the pediatric population.
Conclusions
Multiplex PCR is a promising rapid diagnostic test for meningitis in adults and children in resource-limited settings. Cryptococcus at low fungal burdens in CSF may be missed by BioFire ME.</p
Evaluation of a point-of-care immunoassay test kit ‘StrongStep’ for cryptococcal antigen detection
<div><p>Background</p><p>HIV-associated cryptococcal meningitis is the leading cause of adult meningitis in Sub-Saharan Africa, accounting for 15%–20% of AIDS-attributable mortality. The development of point-of-care assays has greatly improved the screening and diagnosis of cryptococcal disease. We evaluated a point-of-care immunoassay, StrongStep (Liming Bio, Nanjing, Jiangsu, China) lateral flow assay (LFA), for cryptococcal antigen (CrAg) detection in cerebrospinal fluid (CSF) and plasma.</p><p>Methods</p><p>We retrospectively tested 143 CSF and 77 plasma samples collected from HIV-seropositive individuals with suspected meningitis from 2012–2016 in Uganda. We prospectively tested 90 plasma samples collected from HIV-seropositive individuals with CD4 cell count <100 cells/μL from 2016–2017 as part of a cryptococcal antigenemia screening program. The StrongStep CrAg was tested against a composite reference standard of positive Immy CrAg LFA (Immy, Norman, OK, USA) or CSF culture with statistical comparison by McNemar’s test.</p><p>Results</p><p>StrongStep CrAg had a 98% (54/55) sensitivity and 90% (101/112) specificity in plasma (<i>P</i> = 0.009, versus reference standard). In CSF, the StrongStep CrAg had 100% (101/101) sensitivity and 98% (41/42) specificity (<i>P</i> = 0.99). Adjusting for the cryptococcal antigenemia prevalence of 9% in Uganda and average cryptococcal meningitis prevalence of 37% in Sub-Saharan Africa, the positive predictive value of the StrongStep CrAg was 50% in plasma and 96% in CSF.</p><p>Conclusions</p><p>We found the StrongStep CrAg LFA to be a sensitive assay, which unfortunately lacked specificity in plasma. In lower prevalence settings, a majority of positive results from blood would be expected to be false positives.</p></div
Semi-Quantitative titration of the StrongStep LFA as compared to the Immy LFA.
<p>Semi-Quantitative titration of the StrongStep LFA as compared to the Immy LFA.</p
Performance characteristics of the StrongStep LFA in Uganda.
<p>Performance characteristics of the StrongStep LFA in Uganda.</p
Characteristics of CSF and Plasma specimens misclassified by the StrongStep LFA.
<p>Characteristics of CSF and Plasma specimens misclassified by the StrongStep LFA.</p