Traditional descriptions of bacterial meningitis in childhood have stratified causative pathogens on the basis of age. Meningitis in children older than 60 days, called ‘pediatric bacterial meningitis’ is often caused by encapsulated bacteria that colonize the nasopharynx and other body sites. Meningitis in children younger than 60 days, called ‘young infant bacterial meningitis’ is further stratified by gestational age and timing of onset of infection. In general, infections that occur within the first 7 days of life of a term neonate are described as early onset disease, whereas infections occurring from 7 to 60 days after birth are described as late-onset disease.
Causes of Early Onset Meningitis:
The immature immune system compounds the meningitis infection:
The relatively immature immune system of the neonate also contributes to the invasive risk of bacterial pathogens. Defects in phagocytic cell function, chemotaxis, cytokine production, complement pathways, Toll-like receptor responses, and antibody production are further conducive to invasive disease. These defects also include adaptive immunity in response to viral infections, including lymphocyte proliferation and antibody responses. Though significant, these immune defects are transient, likely contributing to the decreased incidence of serious bacterial infections with increasing age.