Méningites néonatales

Neonatal meningitis is particularly dreadful as it occurs on a developing brain with immature immunity. It differs from meningitis in older children and adults by many points that make it difficult to diagnose. The lack of specific clinical signs leads to an increased frequency of lumbar punctures. In this context the sample can be traumatic, making it difficult to analyze, or the sampling can be contra-indicated due to the instability of the newborn, resulting in delayed realization under antibiotic treatment. Group B streptococcus (Streptococcus agalactiae) and Escherichia coli are the two major pathogens responsible of approximately 60 % and 30 % of cases, respectively. The incidence of Listeria monocytogenes has declined to less than 5 %. Other bacteria may be involved such as bacteria with classic meningeal tropism (meningococcus, pneumococcus) or atypical organisms, such as Ureaplasma genus. Viral meningitis is also frequent and unrecognized primarily caused by enteroviruses and parechoviruses which, though often benign, can sometimes be fatal, especially in infants less than 6 days of life. Herpes viruses are responsible for the much rarer meningoencephalitis whose prognosis is extremely serious in the absence of treatment. The small amount of sample available, combined with the difficulties of diagnosis and severity of the prognosis in case of inadequate treatment, makes the diagnosis of neonatal meningitis a challenge that only a perfect collaboration between the pediatrician and the biologist is able to meet.