SEROTYPE-RELATED DIFFERENCES IN INFLAMMATORY RESPONSE TO STREPTOCOCCUS-PNEUMONIAE IN EXPERIMENTAL MENINGITIS

It has been suggested that serotype influences severity of experimenta l pneumococcal meningitis. This hypothesis was tested with strains of serotypes 1, 5, 6B, 7F, 14, and 23F, prevalent in Israel, in an experi mental rabbit model. Cerebrospinal fluid (CSF) bacterial titers, leuko cyte densities, concentrations of lactate, protein, and glucose, tumor necrosis factor-alpha levels, brain water content, and cerebral blood flow were measured 18 h after inoculation of pneumococci. Serotypes 5 and 7F exhibited mild inflammatory responses (leukocytosis <1000/mm(3 ), lactate <4 mmol/L); types 6B, 14, and 23F showed severe inflammator y responses (leukocytosis >5000/mm(3), lactate >10 mmol/L); serotype 1 had intermediate inflammatory responses but exceptionally high CSF ba cterial titers. Leukocyte count correlated with all other variables; l actate with all except brain water content. On the basis of 6 Streptoc occus pneumoniae serotypes, three discrete levels of inflammatory resp onses could be delineated in experimental pneumococcal meningitis.