Nested polymerase chain reaction targeting 16S rRNA gene in diagnosis of acute bacterial meningitis

Abstract

CONTEXT: Diagnosing acute bacterial meningitis (ABM) among children presenting to tertiary health care settings is often difficult because of prior administration of antimicrobials. AIMS: The present study was an attempt to diagnose cases of ABM in children with the help of nested polymerase chain reaction (PCR). SETTINGS AND DESIGN: It is a prospective observational study, in which a total of 84 clinically suspected cases and cerbrospinal fluid (CSF) biochemical parameters suggestive of ABM were included in the study. METHODS AND MATERIAL: CSF samples were subjected to Gram staining, bacterial culture and biochemical identification tests as well as panbacterial nested PCR targeting 16S rRNA gene sequence. Subsequently, a nested multiplex PCR for detection of the three fastidious organisms, viz. Streptococcus pneumoniae, Neisseria meningitidis and Haemophilus influenzae, was performed. STATISTICAL ANALYSIS USED: The sensitivity, specificity, PPV, NPV, LR+, and LR− of the tests were calculated. RESULTS: The sensitivity of Gram stain, bacterial culture, and nested PCR targeting 16SrRNA were observed to be 16.21%, 9.45%, and 97.29% respectively. Further, the NPV and LR− the PCR were found to be 83.33 and 0.02 respectively. Species specific nested multiplex PCR was able to detect S. pneumoniae (n = 7), N. meningitidis (n = 2) and H. influenzae (n = 1). CONCLUSIONS: The results indicates that nested PCR targeting 16S rRNA gene may be used in diagnosis of ABM. Further, nested multiplex PCR targeting the three important fastidious bacterial pathogens in ABM cases has showed their presence in our region.