Immunochromatography in CSF improves data on surveillance of S. pneumoniae meningitis in India

Abstract

S. pneumoniae was detected thrice the number of times by ICT than by CSF culture, with a sensitivity and specificity of 100% and 95.3% respectively. This rapid ICT test proves to be of immense use as a diagnostic test for meningitis patients with/without prior antibiotic treatment, especially in facilities with limited laboratory infrastructure in resource limited settings.

The BinaxNOW antigen detection assay on CSF samples for diagnosis of pneumococcal meningitis

“…Similar high rates of positivity were detected in an international study, and 19.3% were positive by culture/BinaxNOW while only 6.3% by culture/latex agglutination or 1.1% by culture alone among the Asian countries [12]. Meta-analysis by the WHO meningitis group assessed its diagnostic accuracy and found sensitivity and specificity ranging 96-100% and 95-97% respectively [3]. In a study by Picazo et al, when compared with culture or qPCR targeting autolysin gene, the sensitivity and specificity were 88% and 72.5% but both CSF and pleural fluid were tested [13].…”

“…We found the test to have higher sensitivity (90.9%) but lower predictive value (62.5%) when compared with culture. In a recent multicentric study from India, 2081 CSF specimens from children suspected with bacterial meningitis were tested and highlighted the four-fold improvement in detection of pneumococcal meningitis by BinaxNOW assay (6.1% were positive by BinaxNOW test while only 1.5% by culture) [3]. When compared with culture, it had a low positive predictive value (25.6%) but had 100% sensitivity and negative predictive values.…”

“…Originally it was devised to test the presence of pneumococcal antigen in urine samples of patients suspected with pneumococcal pneumonia. However, a few studies extended its use for diagnosis of pneumococcal meningitis and the test has been approved by the United States Food and Drug Administration for diagnosis of pneumococcal meningitis [3]. One advantage of this shift in testing is that the CSF samples do-not contain the antigen while a person is pneumococcal This prospective study was thus undertaken to assess the accuracy of the BinaxNOW antigen detection assay in comparison with real-time PCR (qPCR) for diagnosing pneumococcal meningitis.…”

“…These difficulties were partially resolved when antigen-based assays (like latex agglutination tests or immuno-chromatographic tests) and molecular assays like PCR and real-time PCR were introduced into laboratory diagnosis. The latex agglutination tests although are rapid, they require additional equipment which may hinder their use as a point-of-care test or in resource-poor settings [3].…”

“…Up to 70000 deaths per year of acute bacterial meningitis were reported to be due to this organism alone in developing countries [2]. Despite its medical importance and high prevalence, diagnosis of pneumococcal meningitis may be hampered by many factors like prior antibiotic administration and time lapse before the sample is processed [3]. In developing countries like India, where over the counter availability of antibiotics is very common, it poses a challenge to the treating physician and the microbiologist to establish the etiology of acute bacterial meningitis.…”