Cerebrospinal Fluid Cathelicidin Correlates With the Bacterial Load and Outcomes in Childhood Bacterial Meningitis

BACKGROUND Large cerebrospinal fluid (CSF) bacterial load in bacterial meningitis (BM) relates to poor outcome. However, the antimicrobial peptide cathelicidin seems important to host defense. We studied how cathelicidin concentrations and bacterial load in CSF relate in childhood BM and to what extent they may predict the disease outcome. METHODS The patient data originated from a large prospective clinical trial in Latin America in 1996-2003 in which the CSF samples were collected on admission (CSF1) and 12-24 hours later (CSF2). The cathelicidin concentrations were measured by enzyme-linked immunosorbent assay and the CSF bacterial load by real-time polymerase chain reaction. This analysis comprised 76 children with meningitis caused by Haemophilus influenzae type b (n = 44), Streptococcus pneumoniae (n = 28) or Neisseria meningitidis (n = 4). RESULTS The cathelicidin concentration correlated with the bacterial genome count in both samples (CSF1: ρ = 0.531, P < 0.001; CSF2: ρ = 0.553, P < 0.001). A high CSF1 ratio of cathelicidin to the bacterial genome count was associated with fewer audiologic sequelae (odds ratio: 0.11, 95% confidence interval: 0.02-0.61, P = 0.01) and more favorable neurologic outcomes (odds ratio: 3.95, 95% confidence interval: 1.22-12.8, P = 0.02), but not with better survival. CONCLUSIONS In conclusion, CSF cathelicidin and the bacterial load were closely related in childhood BM. A high initial cathelicidin-to-bacterial genome count ratio predicted better outcomes in survivors.