Evaluation of Real-Time Polymerase Chain Reaction in Culture-Negative Cerebrospinal Fluid Samples of Bacterial meningitis Patients

Background: Meningitis is a rigorous childhood disease with high morbidity and mortality. It is the main cause of under five mortality in India. Mainly three bacteria Streptococcus pneumoniae, Neisseria meningitidis, and Haemophilus influenzae are responsible. In low economic set up country like India, documented bacterial meningitis mainly depend on gram staining, cerebrospinal fluid (CSF) culture results or latex agglutination test resulting in less number of positive due to the prior antimicrobial intake which affects culture and latex agglutination test results. This study was taken up rapid and accurate molecular method like RT PCR to diagnose bacterial meningitis in culture-negative CSF samples.

Materials and Methods: Fifty culture-negative CSF samples from suspected cases of bacterial meningitis were examined by real-time polymerase chain reaction (real-time PCR) for the presence of lytA, bexA, and ctrA genes specific for Streptococcus pneumoniae, Haemophilus influenzae, and Neisseria meningitidis respectively.

Results: Positive real-time PCR results for Streptococcus pneumoniae were detected in 36 (72%) of culture-negative CSF samples while 10% positive results for Haemophilus influenzae type b. Nine (18%) samples were negative by real-time PCR for all tested organisms.

Conclusion: The use of molecular techniques as real-time PCR can provide a valuable addition to the proportion of diagnosed cases of bacterial meningitis especially in settings with high rates of culture-negative results.