There are different organisms reponsible for early and late neonatal sepsis.
The microorganisms most commonly associated with early-onset infection include the following:
• Group B Streptococcus (GBS)
• Escherichia coli
• Coagulase-negative Staphylococcus
• Haemophilus influenzae
• Listeria monocytogenes
Late-onset sepsis occurs at 4-90 days of life and is acquired from the caregiving environment. 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