[Optimization of real-time multiplex polymerase chain reaction for the diagnosis of acute bacterial meningitis and Neisseria meningitidis serogrouping].


Guldemir D. , Turan M., Bakkaloglu Z., Nar Otgun S., DURMAZ R.

Mikrobiyoloji bulteni, vol.52, no.3, pp.221-232, 2018 (Journal Indexed in SCI Expanded) identifier identifier identifier

  • Publication Type: Article / Article
  • Volume: 52 Issue: 3
  • Publication Date: 2018
  • Doi Number: 10.5578/mb.67019
  • Title of Journal : Mikrobiyoloji bulteni
  • Page Numbers: pp.221-232

Abstract

Streptococcus pneumoniae, Neisseria meningitidis and Haemophilus influenzae type B are responsible for about 80-85% of acute bacterial meningitis cases among adults and in our country it is mandatory to report bacterial meningitis cases caused by these agents. In recent years, disease control programs have focused especially on these three pathogens in our country. It is very important to know the causative agent of meningitis for prevention/control measures, choice of treatment regimen, and prediction of the severity and the course of the disease. Rapid diagnosis of meningococcal meningitis is especially vital. In addition, the identification of N.meningitidis serogroups in the community is also important for the decision of the type and combination of vaccine to be administered. The aim of this study was to optimize the real-time multiplex polymerase chain reaction (Rt-multiplex PCR) for the diagnosis of the disease and serogrouping of N.meningitidis in clinical samples in a direct, quick and reliable way. In this study, three Rt-multiplex PCR assays were optimized and standardized for the detection of N.meningitidis, H.influenzae and S.pneumoniae (NHS mix) and for the serogrouping of N.meningitidis (BCY mix and AWX mix) in our laboratory. Sensitivity of the Rt-multiplex PCR method was detected by reference strains and simulation studies. Forty three samples (41 cerebrospinal fluid (CSF), 1 serum and 1 clinical isolate) with the suspicion of acute bacterial meningitis and six nasopharyngeal isolates sent to National Reference Laboratory for Molecular Microbiology between July 2012-May 2014 were included in the present study. All samples were examined with the Rt-multiplex PCR methods. Clinical isolates were studied by both conventional and Rt-multiplex PCR methods. Oxidase, catalase test, Gram stain, API-NH and agglutination tests with specific antisera were performed in the National Respiratory Pathogens Reference Laboratory. The detection limit of the method, which was optimized and standardized in our laboratory was determined as 10(2) cfu/ml. The CT (threshold cycle) value in this dilution was detected approximately as 35. N.meningitidis was detected in 14 of the 41 CSF samples by the NHS mix. However, only 10 of the positive samples could be typed with BCY mix and AWX mix. Eight (80%) of them were serogroup B, one of each was (10%) serogroup A and serogroup W135, respectively. All the isolates (six nasopharyngeal and one clinical specimen) were identified as N.meningitidis serogroup B by Rt-multiplex PCR and the isolates were also confirmed by conventional methods. The CSF specimens with CT value > 35 could not be typed. We concluded that the Rt-multiplex PCR method is a rapid and reliable test for the direct diagnosis of acute bacterial meningitis due to NHS and serogrouping of N.meningitidis. Rapid diagnosis plays an important role for the treatment and control of the disease, and serogrouping of the agent plays an important role in terms of prevention/control and vaccination policies.