What is the most common cause of meningitis in neonates?

Group B Streptococcus (GBS) is the most common cause of meningitis in neonates. This bacterium is part of the normal flora in pregnant women but can cause serious infections in newborns, particularly in the first week of life. During labor, the bacteria can be transmitted from the mother to the infant, leading to conditions such as meningitis, sepsis, and pneumonia in the neonate.

The risk of GBS infection in neonates is substantial if the mother is a carrier, which is why screenings and interventions, such as antibiotic prophylaxis during labor, are important in preventing neonatal infections. This emphasis on GBS is particularly relevant given that it has been a primary focus of public health initiatives to reduce the incidence of early-onset disease in newborns.

Escherichia coli can also cause meningitis in neonates, particularly in cases involving preterm birth or prolonged rupture of membranes, but it is less common than GBS. Streptococcus pneumoniae and Neisseria meningitidis generally affect older children and adults more frequently than neonates. Therefore, GBS stands out as the predominant pathogen responsible for meningitis in this vulnerable population.