Group B Streptococcus (Streptococcus agalactiae) is the most common cause of neonatal bacterial meningitis beyond one week of age.
Step-by-Step Justification:
* Group B Streptococcus (GBS) and Neonatal Infections:
* GBS is a leading cause of late-onset neonatal meningitis (occurring after 7 days of age).
* Infection typically occurs through vertical transmission from the mother or postnatal exposure.
* Neonatal Risk Factors:
* Premature birth, prolonged rupture of membranes, and maternal GBS colonization increase risk.
Why Other Options Are Incorrect:
* A. Group A: Rare in neonates and more commonly associated with pharyngitis and skin infections.
* C. Group C: Typically associated with animal infections and rarely affects humans.
* D. Group D: Includes Enterococcus, which can cause neonatal infections but is not the most common cause of meningitis.
CBIC Infection Control References:
* APIC Text, "Group B Streptococcus and Neonatal Meningitis".