Value of multiplex PCR using cerebrospinal fluid for the diagnosis of ventriculostomy-related meningitis in neurosurgery patients

This prospective observational cohort study assessed the use of a multiplex real-time polymerase chain reaction (PCR) assay alone and in conjunction with biomarkers for the diagnosis of ventriculostomy-related meningitis in neurosurgery intensive care unit (ICU) patients with external ventricular drainage (EVD). Concentrations of intrathecal biomarkers, including lactate and interleukin 6 (IL-6), were measured, and cerebrospinal fluid (CSF) was examined microbiologically by blood culture BACTEC bottles in 62 CSF samples from 41 patients with EVD. A portion of each sample was also tested with a commercially available PCR assay that simultaneously detects 25 species of bacteria and fungi [SeptiFast (SF)]. Receiver operating characteristic curve analysis was used to compare biomarker concentrations with SF and culture results. Seventeen (27 %) samples tested positive and 40 (65 %) tested negative for pathogens by both culture and SF. One pathogen was detected only by SF. Four samples tested positive by culture but negative by SF; in 3 of these, the isolates were considered to be contaminants. In comparison to CSF culture SF showed a larger area under the curve for IL-6 (0.90; 95 % CI 0.83-0.98) versus 0.70 (95 % CI 0.46-0.80) and for lactate (0.77; 95 % CI 0.63-0.93) versus 0.65 (95 % CI 0.50-0.80). In 94 % (17/18) of positive SF samples the results were obtained on the same day whereas the overall mean of the time-to-positivity of BACTEC bottles was 21.6 h. The diagnosis of EVD-related ventriculo-meningitis in neurosurgical ICU patients can be established in a rapid manner using a multiplex PCR assay on CSF samples in combination with intrathecal biomarkers.