The right answer is Escherichia coli.
After birth, the term newborn and a fortiori the premature are very vulnerable to infection (germs of the mother and the entourage) and a rigorous hygiene is essential to avoid this post-natal infection. Neonatal infection is a major cause of morbidity and mortality. The diagnosis must be early in order to start an effective treatment quickly. The treatment is urgent because an infection can kill a newborn in a few hours.
Among the most commonly involved germs are Streptococcus B followed by Escherichia coli (which already exists in the human intestinal flora) by causing meningitis. Other agents may also be involved: Staphylococcus, listeriosis agent, gonococcus, anaerobes, etc.