A 4-hour-old baby boy, born by vaginal delivery at 36 weeks' gestation, is noticed by his mother to be making a grunting noise when he breathes. On exam the infant is irritable, pale, and floppy. He has an increased respiratory rate (65 breaths per minute), tachycardia (170 bpm), and low blood pressure (45/25 mmHg). His temperature is 97°F (36.2°C). Blood tests reveal leukopenia, neutropenia, thrombocytopenia, and a blood glucose level of 45 mg/dL. The pregnancy had been uneventful. However, the labor was complicated by a presumed premature rupture of membranes approximately 18 hours before the delivery, and a maternal temperature of 100°F (38°C) 3 hours before delivery. Group B streptococcal carriage had not been screened for, but antibiotic prophylaxis had been given 30 minutes before delivery.