Endotoxin in Cerebrospinal Fluid: Detection in Neonates With Bacterial Meningitis

The Limulus lysate assay was used to measure endotoxin in 307 cerebrospinal fluid (CSF) specimens from 84 infants with meningitis caused by Gram-negative bacteria. Endotoxin was detected in 117 CSF samples (38%), and its presence was correlated with recovery of bacteria from CSF cultures. A direct relationship was demonstrated between the presence, persistence, and concentration of endotoxin in CSF and outcome from meningitis. Measurement of CSF endotoxin by the Limulus assay and of CSF K1 antigen by counterimmunoelectrophoresis (CIE) showed a significant correlation between the presence and amount of these two Escherichia coli K1 capsular substances. Endotoxin was detected in 72% of infants, and 52% had K1 antigen in CSF specimens obtained within 24 hours of diagnosis. Combining the results of the Limulus assay and CIE, 81% of patients with E coli K1 meningitis had endotoxin or K1 or both in initial CSF samples.