16S PCR assay for the evaluation of CSF in CNS infections

• Research type

  Research Study

• Full title

  16S PCR assay for the evaluation of CSF in Neurosurgical and Central Nervous System infections

• IRAS ID

  136556

• Contact name

  Liba Stones

• Contact email

  liba.stones@nhs.net

• Sponsor organisation

  King's College Hospital

• Research summary

  Introduction

  Infections of the central nervous system (CNS) are a cause of significant morbidity and mortality with neurosurgical infections having a variable prevalence and incidence ranging from 5 to 15 percent for internalised device infection and 5 to 10 percent for externalised device infection. Making the right diagnosis is crucial for the optimal management of these infections. This is achieved through a combination of clinical, radiological and laboratory criteria. However, given that these patients have often had antibiotics exposure prior to cerebrospinal fluid (CSF) sampling, this poses a challenge in that a negative CSF culture cannot definitively exclude CNS infection. Hence the need for a more sensitive non-culture based diagnostic assay for the detection of bacterial pathogens in this clinical setting.

  The 16S PCR assay is a broad-range polymerase chain reaction that detects bacterial 16S ribosomal DNA gene. It is a highly sensitive assay as it amplifies 16S rDNA fragment of any bacteria present in the clinical sample. Hence with appropriate precautions in place to prevent contamination, a positive test result is useful in the right clinical context suggesting bacterial infection and may also re-confirm a positive culture result. In addition, the high negative predictive value of the assay would be highly relevant in informing clinical decision to review unnecessary antibiotic use and hence prevent potential drug adverse events. A negative PCR and culture result would also help to reassure the clinical team to safely proceed with further staged interventions such as placement of definitive/permanent CSF shunts.

  Aim

  The aim of this study is to determine the utility of broad-range polymerase chain reaction in the evaluation of CSF samples for CNS infections.

  Objectives

  The study objectives will include:

  .To compare 16S PCR test results with CSF culture in order to determine concordance and discordant rates

  . To determine any correlation between culture, 16S PCR and infection markers (i.e CRP, WBC, fever).

  Methods

  Project design: Prospective observational study.

  Specimen/Data collection: Consecutive CSF samples from patients sent to the Microbiology laboratory at King’s College Hospital will be processed/analysed and in addition tested by 16S PCR in accordance with local standard operating procedure.

  Inclusion criteria:
   All CSF samples received for processing in the Microbiology laboratory

  Exclusion criteria:
   Inappropriate sample (i.e contaminated CSF leak specimen collected from the nostril)
   Inadequate sample

  Controls: CSF sample collected for indications other than infection (i.e subarachnoid haemorrhage)

  Materials required: Rotorgene PCR machine in the research microbiology laboratory of King’s College Hospital will be used for this study.

• REC name

  North East - Newcastle & North Tyneside 2 Research Ethics Committee

• REC reference

  14/NE/0110

• Date of REC Opinion

  2 Apr 2014

• REC opinion

  Favourable Opinion