[Factors of meningeal diffusion of amoxicillin and ampicillin at the acute phase of purulent meningitis in children].

Amoxicillin and ampicillin levels were comparatively studied in blood and CSF of children with purulent meningitis. Thirty one children aged 2 months to 11 years were treated by one of two beta lactams by monotherapy in a daily dose of 200 mg/kg (Group 1: amoxicillin, n = 17; group 2: ampicillin, n = 14). Samples were collected on day 2 one hour after administration of 50 mg/kg IV of the chosen antibiotic. The mean levels observed in serum (69.5 and 53.4 micrograms/ml) and in CSF (7.74 and 7.96) were not significantly different. Beyond these levels we studied different biologic parameters in CSF: leucocytes, polymorphonuclears, protein, glucose and lactic acid. Multiple linear correlations were found, for the two groups and for the whole population between the CSF antibiotic level and the 6 other parameters (group 1: R1 = 0.82; group 2: R2 = 0.88; group 1 + 2: R3 = 0.78). The best correlated parameters with antibiotic CSF level are serum antibiotic level and CSF lactic acid. With these two parameters we can also estimate antibiotic level in CSF with good correlations (R1 = 0.78; R2 = 0.72 and R3 = 0.72).