Which organism is commonly seen in late-onset sepsis in neonates?

• A. Group A Streptococcus.
• B. Listeria monocytogenes.
• C. Coagulase-negative Staphylococci (CoNS) are commonly seen in late-onset sepsis in neonates.
• D. Streptococcus pneumoniae.

Answer: (C)

In late-onset neonatal sepsis, organisms tied to the NICU environment and invasive devices are most common. Coagulase-negative Staphylococci, especially Staphylococcus epidermidis, fit this pattern. They normally live on skin, but when a newborn requires central lines or catheters, these bacteria can travel along those devices into the bloodstream. Their strong ability to form biofilms on indwelling hardware makes them persistent and relatively hard to eradicate with antibiotics, so they are a frequent cause of bacteremia in preterm or very sick infants with lines or parenteral nutrition.

Clinically, infections with these organisms can be subtle, and blood cultures may reflect skin flora contamination. Yet when there is a consistent clinical picture and repeated positive cultures from sterile sites, it supports true infection rather than a harmless contaminant. Management focuses on removing or replacing the contaminated line when possible and using antibiotics guided by susceptibility, with vancomycin often used because methicillin-resistant strains are common in NICUs.

As a reference point, early-onset sepsis in newborns is more commonly caused by organisms like Group B Streptococcus and E. coli, while Listeria and Streptococcus pneumoniae are less typical causes of neonatal sepsis.