Severe community-acquired meningitis

From birth until the first month of life, Streptococcus agalactiae, Listeria monocytogenes and Enterobacteriaceae (especially Escherichia coli) are the main pathogens. From 2 months until 4 years of age, meningitis is principally due to Haemophilus influenzae type B (the incidence of which is dramatically decreasing because of widespread vaccination), Neisseria meningitidis and Streptococcus pneumoniae. In children, teenagers and young adults, N. meningitidis and S. pneumoniae represent more than 80% of the cases. Above the age of 60 years, S. pneumoniae and H. influenzae are the most frequently isolated bacteria [1,2].When all of these bacteria are taken together, the elements that indicate a poor prognosis are as follows: age less than 1 month or greater than 45 years; worsening level of consciousness on admission; and forms with purpura fulminans [3,4,5,6]. In the absence of a specific treatment, purulent meningitis is ultimately fatal.Pneumococcal meningitis is the most frequent cause of bacterial meningitis in those older than 30 years, and was responsible for 20% of cases of purulent community meningitis in children and 60% of adult cases in France in 1993. It is also more severe in terms of mortality (15–30%) and morbidity (deafness).The increasing resistance of S. pneumoniae to penicillin (in more than 10% of isolates) has created a problem for therapy, which at present cannot be completely optimized and requires a knowledge of the sensitivity phenotype of the bacteria in question. Penicillin-resistant pneumococci (PRP) include pneumococci with an intermediate sensitivity [minimum inhibitory concentration (MIC) of between 0.12 and 1 mg/l] and highly resistant pneumococci (MIC = 1 mg/l).Resistance to β-lactams is related to modifications of the genes coding for penicillin-linked proteins (PLPs), which are the active sites for all β-lactams, especially PLP2b and PLP2x [7]. Such genomic change is due either to a genetic transfer or to on-off mutations. The main