<prompt> Organism causing Early onset neonatal septicemia :Streptococcus agalactiaeStreptococcus bovisStreptococcus pyogenesStreptococcus viridans  <response>: Early-onset sepsisless 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 sepsis72hrs 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 