This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: New born infants, Subject name: Pediatrics
Organism causing Early onset neonatal septicemia : 
Select and explain. 
A. Streptococcus agalactiae, B. Streptococcus bovis, C. Streptococcus pyogenes, D. Streptococcus viridans
A: Streptococcus agalactiae
Answer: A: Streptococcus agalactiae 
Explanation: *Early-onset sepsis(less than 72 hrs) is caused by organisms prevalent in the maternal genital tract or in the delivery area. *The microorganisms most commonly associated with early-onset infection include the following : Group B Streptococcus (GBS)- Streptococcus agalactiae, Escherichia coli, Coagulase-negative Staphylococcus, Haemophilus influenzae, Listeria monocytogenes. *Late onset sepsis(72hrs or later) is caused by organisms thriving in the external environment of the home or the hospital. *Organisms that have been implicated in causing late-onset sepsis include the following: Coagulase-negative Staphylococcus, Staphylococcus aureus, E coli, Klebsiella, Pseudomonas, Enterobacter, Candida, GBS, Serratia, Acinetobacter, Anaerobes* No investigation is required to sta the treatment in a sick baby. Reference : page 160 Ghai Essential Pediatrics 9 th edition