Cerebrospinal Fluid Culture versus Multiplex Real Time PCR in the Diagnosis of Bacterial Meningitis

Abstract

Background: Streptococcus pneumoniae and Neisseria meningitidis are the most common causative bacteria and are associated with high mortality and morbidity. Early diagnosis and treatment of bacterial meningitis is critical, and a high index of clinical suspicion is essential. While the CSF culture is the gold standard in the diagnosis of bacterial meningitis, the low bacterial growth rates particularly in the patients who have received antibiotic treatment before the lumbar puncture necessitated the development of new test methods  Polymerase chain reaction (PCR) has the advantage of being relatively rapid and is able to detect low amounts of bacteria in the CSF. Methods: Eighty seven   CSF specimens were collected from children aged 5 years  to 15 years, CSF biochemical analysis, culture and gram stain was performed. PCR assay was performed on 87 of CSFʹs specimens selected as bacterial meningitis depending on the data of request forms (cell count, type of cells predominant, glucose, and protein levels. PCR was done in multiplex and duplex to amplify different fragments of genes under study in a single tube for detecting H.influenzae , N. meningitis and S. pneumonia. Results:The mean age of patients was 8.75  ± 3.49. there was  24 (60.0%) males and 16 (40.0 %) females. CSF culture  showed that    (19.5%) overall  positive bacterial  CSF culture Streptococcuspneumonia and 6 were Neisseria meningitides and no single growth of H. Influenze. Using multiplex PCR, twenty-seven samples (31.1%) were positive for Streptococcus pneumoniae and Neisseria meningitidis were positive in 13 (14.9%) of the patients, whereas Haemophilus influenzae were not detected in any of the samples (0%). Forty-seven  samples (54.0 %) were negative for all three organisms.