Which of the following treatments is the initial choice for a newborn with presumptive GBS?

The initial treatment choice for newborns with presumptive Group B Streptococcus (GBS) infection focuses on the regimen that provides effective coverage while being safe and appropriate for neonates. Ampicillin, often paired with an aminoglycoside like Gentamicin, is a preferred treatment option due to its efficacy against GBS, which is a leading cause of early-onset sepsis in newborns.

Ampicillin specifically targets the GBS bacteria and is well-tolerated in this population. The addition of an aminoglycoside can offer a broader spectrum of coverage, especially when there is a risk of co-infection, which is critical in managing ill-appearing infants or those with high-risk factors for sepsis.

Using Penicillin V or Ceftriaxone, on the other hand, is less appropriate in this acute scenario. Penicillin V is not typically used in the acute care setting for serious infections in neonates because it is administered orally and is not suitable for immediate IV therapy. Ceftriaxone, while it has broad-spectrum activity, is not indicated for GBS and may actually lead to biliary sludging in neonates, making it a less favorable option.

Choosing the combination of Ampicillin and an amin