Detection of pneumolysin in cerebrospinal fluid for rapid diagnosis of pneumococcal meningitis

Background & objectives: Pneumolysin, a toxin produced by Streptococcus pneumoniae is associated with virulence and is found in all invasive isolates. Its role as a diagnostic too[ has recently been exploited. Most of the methods used are based on molecular techniques and are not cost-effective. The present study was undertaken to evaluate a simple, rapid and cost-effective method to detect pneumolysin in CSF as a diagnostic test for pneumococcal meningitis. Methods: A total of 75 CSF samples from children with presumptive diagnosis of acute pyogenic meningitis or encephalitis were subjected to Gram stain, culture and pneumolysin detection by Cowan 1 staphylococcal protein A co-agglutination technique. Results: Pneumolysin was detected in 26(78.8%) of 33 culture proven CSF samples and 4(9.5%) of 42 culture negative samples. Antigen detection by Co-A had a specificity of 90 per cent and a sensitivity of 79 per cent when compared with culture. Compared to Gram stain, pneumolysin Co-A had a specificity and sensitivity of 91.0 and 92.0 per cent respectively. Interpretation & conclusion: Detection of pneumolysin was found to be a simple, low cost antigen detection assay for rapid diagnosis of pneumococcal meningitis, for routine use in the developing countries.