Exosomes in cerebrospinal fluid as biomarkers of bacterial infections of the central nervous system: a pilot study

Introduction: Intracranial infections present a significant diagnostic challenge. This pilot study aimed to evaluate the potential of cerebrospinal fluid (CSF)-derived exosomes as novel diagnostic biomarkers for bacterial central nervous system infections. Methods: We enrolled nine patients from Changsha Central Hospital, forming three groups: culture-confirmed intracranial infection (n=3), cerebral hemorrhage with bloody CSF (n=3), and cerebral hemorrhage with clear CSF (n=3). Exosomes were isolated from CSF via ultracentrifugation and characterized using transmission electron microscopy and nanoparticle tracking analysis to assess morphology, concentration, and particle size. Statistical differences between groups were analyzed. Results: Exosomes were successfully detected in all but one clear-CSF patient. The infected CSF group exhibited a significantly higher mean exosome concentration (1.37e+11 ± 4.40e+10 particles/ml) compared to the bloody (4.08e+9 ± 1.95e+9 particles/ml) and clear CSF groups (1.10e+9 ± 0.56e+9 particles/ml; both p