Etiology of Neonatal Bacterial Meningitis The predominant pathogens are Group B streptococcus (GBS—predominantly type III) Escherichia coli (particularly those strains containing the K1 polysaccharide) Listeria monocytogenes Other reported pathogens include enterococci, nonenterococcal group D streptococci, alpha-hemolytic streptococci, Staphylococcus aureus, coagulase-negative staphylococci, gram-negative enteric organisms (eg, Klebsiella species, Enterobacter species, Citrobacter diversus), Haemophilus influenzae, Neisseria meningitidis, and Streptococcus pneumoniae.