Meningitis in the Neonate

Group B beta-hemolytic streptococci and Escherichia coli strains account for approximately two thirds of all cases of neonatal meningitis, while bacteria that typically account for meningitis in older age groups (Haemophilus influenzae type B, Neisseria meningitidis, and Streptococcus pneumoniae) are infrequent causes of meningitis in the neonatal population. As with other medical problems in neonates, signs and symptoms of bacterial infection of the central nervous system are generally few in number and nonspecific in nature. Manifestations that can suggest meningitis, as well as other serious illnesses, include temperature instability, lethargy, respiratory distress, poor feeding, vomiting, and diarrhea. Signs suggestive of meningeal irritation, including stiff neck, bulging fontanelle, convulsions, and opisthotonus, occur only in a minority of neonates with bacterial meningitis and cannot be relied on solely to identify such patients. Ampicillin and either gentamicin or cefotaxime are recommended for initial empiric therapy of neonatal meningitis. When the results of the cerebrospinal fluid (CSF) culture and susceptibilities are known, therapy can be narrowed to cover the specific pathogen identified. In general, penicillin G or ampicillin is preferred for group B streptococcal meningitis, ampicillin for Listeria monocytogenes meningitis, and ampicillin plus either an aminoglycoside or cefotaxime for gram-negative meningitis. For the very low birth weight neonate who has been in the nursery for a prolonged period of time, organisms such as enterococci and gentamicin-resistant gram-negative enteric bacilli must also be considered. In patients with long-term vascular catheters, Staphylococcus aureus or coagulase-negative staphylococci must also be considered. Empiric combinations of antibiotics for such patients would include ampicillin or vancomycin, plus amikacin or cefotaxime. All neonates should undergo repeat CSF examination and culture at 48 to 72 hours after initiation of therapy. If organisms are observed on gram stain, modification of the therapeutic regimen should be considered, and neuroimaging should be performed. In general, therapy should be continued for 14 to 21 days for neonatal meningitis caused by group B streptococci or L. monocytogenes, and for at least 21 days for disease caused by gram-negative enteric bacilli. All patients with neonatal meningitis should have hearing and development monitored serially. The first audiologic evaluation should occur 4 to 6 weeks after resolution of the meningitis.