Pneumococcal meningitis and endotoxemia: A cross-sectional clinical study

INTRODUCTION: Lipopolysaccharide (LPS) is a major virulence factor during both meningococcal and Haemophilus influenzae meningitis. Pneumococcus does not produce LPS but could be responsible for bacterial digestive translocation as a consequence of sepsis. We addressed this question in the context of pneumococcal meningitis. METHODS: A cross-sectional study on 24 patients with pneumococcal meningitis (20 (83%) admitted in intensive care unit, 4 (17%) with septic shock) and 34 prospectively-enrolled healthy volunteers. Interleukin 6 and C-reactive proteins plasma concentrations were measured as markers of systemic inflammation. Endotoxemia was measured using mass spectrometry (LC-MS/MS) for detection of molecules bound to the lipid A, namely 3-OH fatty acids. RESULTS: Meningitis patients had significantly higher levels of plasma C-reactive protein (237 (74-373) vs. 2 (2-2) mg/l, p < 0.001 and interleukin 6 (43 (13-128) vs. 4.6 (4.6-16.6) pg/ml; p < 0.001) than healthy volunteers. However, we observed no significant difference in plasma lipopolysaccharide concentrations between patients and healthy volunteers (674 (554-896) vs. 668 (623-777) pmol/ml; p = 0.546). CONCLUSIONS: Our results suggest that LPS is not a key determinant of the excessive inflammation associated with severe forms of pneumococcal meningitis.