This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made.

<b><i>Background:</i></b> Central nervous system (CNS) infectious diseases are common diseases in emergency rooms and neurology departments. CNS pathogen identification methods are time consuming and expensive and have low sensitivity and poor specificity. Some studies have shown that bacteria and viruses can produce specific volatile organic compounds (VOCs). The aim of this study is to find potential biomarkers by VOC analysis of cerebrospinal fluid (CSF) in patients with bacterial and viral meningitis/encephalitis (ME). <b><i>Methods:</i></b> CSF samples from 16 patients with bacterial ME and 42 patients with viral ME were collected, and solid-phase microextraction combined with gas chromatography-mass spectrometry was used to analyze the metabolites in the CSF. <b><i>Results:</i></b> There are 2 substances (ethylene oxide and phenol) that were found to be different between the 2 groups. Ethylene oxide was significantly greater in the group of bacterial ME patients than in the viral ME group of patients (<i>p</i> &#x3c; 0.05). In addition, phenol was remarkably increased in the group of ME patients compared with the bacterial ME patients (<i>p</i> &#x3c; 0.05). <b><i>Conclusions:</i></b> Ethylene oxide and phenol may be potential biomarkers to distinguish bacterial ME and viral ME. VOC analysis of CSF may be used as a supporting tool for clinical diagnosis.

Background Central nervous system (CNS) infectious diseases are common diseases in emergency rooms and neurology departments. CNS pathogen identification methods are time-consuming and expensive and have low sensitivity and poor specificity. Some studies have shown that bacteria and viruses can produce specific volatile organic compounds (VOCs). The aim of this study is to find potential biomarkers by VOC analysis of cerebrospinal fluid (CSF) in patients with bacterial and viral meningitis/encephalitis (ME). Methods CSF samples from 16 patients with bacterial ME and 42 patients with viral ME were collected, and solid-phase microextraction (SPME) combined with gas chromatography-mass spectrometry (GC-MS) was used to analyze the metabolites in the CSF. Results There are two substances (Ethylene oxide and Phenol) that were found to be different between the two groups. Ethylene oxide was significantly greater in the group of bacterial ME patients than in the viral ME group of patients (P < 0.05). In addition, phenol was remarkably increased in the group of ME patients compared with the bacterial ME patients (P < 0.05). Conclusions Ethylene oxide and phenol may be potential biomarkers to distinguish bacterial ME and viral ME. VOC analysis of CSF may be used as a supporting tool for clinical diagnosis.