Real-time PCR Detection of the Most Common Bacteria and Viruses Causing Meningitis

Central nervous system (CNS) infections require prompt diagnosis, as the clinical condition progresses rapidly and may lead to severe permanent sequelae or death. The causative agents include viruses, bacteria, fungi, and parasites. In this study, samples with the diagnosis of CNS infection based on cerebrospinal fluid (CSF) sent to us from other hospitals/labs, were studied by multiplex real-time Polymerase Chain Reaction (PCR) method. The purpose of this study is to demonstrate, retrospectively, the most common bacteria and viruses causing meningitis and seasonal distribution of these agents using the multiplex real-time PCR method in CSF samples.

This study retrospectively evaluated the results of 470 CSF specimens that had been sent to the Molecular Unit of our hospital with a pre-diagnosis of CNS infection and had been tested with the PCR method between January 2014 and December 2015. Specimens were tested using multiplex real-time PCR assay for Adenovirus (AdV), Cytomegalovirus (CMV), Enteroviruses (EV) (Polioviruses, Coxackieviruses, Echoviruses, and other enteroviruses), Epstein- Barr virus (EBV), Herpes simplex virus 1 and 2, Human Herpes virus 6 and 7, Varicella-zoster virus (VZV), Human Parechoviruses and Parvovirus B19, Hemophilus influenzae, Streptococcus pneumoniae or Neisseria meningitidis. (FTD NEURO9 and FTD Bacterial meningitis, multiplex real-time PCR Kit).

A bacterial or viral agent was identified in 98 (21%) of the 470 CSF samples. Of the patients, 85% were children and 15% were adults. Of the 98 positive samples, 22 (22.5%) patients were 15 years or older, and the remaining 76 (77.5%) were younger than 15 years. While Enterovirus (25%) was the most frequently identified agent, Adenovirus ranked second (22%) and Streptococcus pneumoniae ranked third (15%) in total. Positivity was highest in the 0 - 5-year age range. Bacteria were detected with the PCR method in 22 patients: S. pneumonia in 14, and N. meningitidis in 8. In cultures, S. pneumonia grew only in 7 and N. meningitidis in one. EV and AdV were seen in the summer months. The two coexisted in 3 (3%) patients.

Early diagnosis and treatment of meningitis are very important for reducing its mortality and morbidity. In patients with suspected meningitis, early detection of the responsible agents may be possible with molecular methods, such as PCR. Significant economic benefits may be obtained by preventing unnecessary antibiotic use and hospitalizations through the early detection of the microbial agents.