The document discusses three case scenarios involving newborn infants admitted to the NICU with prematurity, low birth weight, respiratory distress, and sepsis. For the first case, the recommended choice of antibiotic is ampicillin and gentamicin. For the second case where the baby develops lethargy, the next choice of antibiotic discussed is vancomycin plus an aminoglycoside. The third case involves a baby with late onset sepsis who is treated with multiple courses of antibiotics and develops recurrent infections. Empiric antibiotic therapy for newborns and the bacterial etiology of neonatal sepsis is also summarized.