Final answer:
Streptococcus agalactiae is the most common cause of meningitis in newborns.
Step-by-step explanation:
There are several bacteria that can cause meningitis in newborns, including Listeria monocytogenes, Escherichia coli, Streptococcus agalactiae, Haemophilus influenzae, Neisseria meningitidis, and Streptococcus pneumoniae. However, in the case of a newborn, the most common cause of meningitis is Streptococcus agalactiae (also known as Group B streptococcus or GBS).
This bacterium is commonly found in the microbiota of the vagina and gastrointestinal tract and can be transmitted from the mother to the newborn either before or during birth.