Early-onset Neonatal Sepsis in a Premature Infant

Abstract

A male infant was born at 31 weeks of gestation by spontaneous vaginal delivery. He was the second child of a 25-year-old mother who had regular prenatal care and presented with preterm labor and spontaneous rupture of membranes. The mother reported having flu-like symptoms with low-grade fever and myalgia over the preceding week, for which she had no evaluation or treatment. She received 2 doses of intramuscular dexamethasone to enhance fetal lung maturity and magnesium sulfate for fetal neuroprotection. The baby was delivered 24 hours later through green-tinged amniotic fluid with Apgar scores of 7 and 9 at 1 and 5 minutes, respectively. Growth parameters at birth were at the 50th–75th percentiles with a weight of 1920 grams, length of 42 cm, and occipitofrontal circumference of 29 cm. The respiratory rate of the baby was 70 breaths per minute and oxygen saturation was 90%–95% while receiving fractionated oxygen of 30% via continuous positive airway pressure. He had mild subcostal retractions and intermittent grunting, but the remainder of his physical examination was normal. Chest radiograph showed mild symmetric ground-glass opacification in both lung fields, consistent with respiratory distress syndrome (RDS). Complete blood count revealed a white blood cell count of 21,900/mm3 (with differential of 53% neutrophils, 34% lymphocytes, 11% monocytes, 1% eosinophils, and 1% basophils), hemoglobin (Hb) of 11.1 gm/dL, and platelet count of 324,000/mm3. Reticulocyte count was 5%, total bilirubin was 5 mg/dL and direct comb’s test was negative. A blood culture was obtained, and the patient was empirically treated with ampicillin (100 mg/kg/dose every 12 hours) and piperacillin/tazobactam (100 mg/kg/dose every 12 hours). Twelve hours later, the baby developed increased work of breathing, increasing FiO2 requirement and worsening respiratory acidosis. A repeat chest radiograph showed worsening RDS. Accordingly, the baby was intubated and given surfactant and then was extubated and restarted on continuous positive airway pressure. His respiratory status improved, and with no growth from blood culture after 48 hours of incubation, antibiotics were discontinued. A subsequent result confirmed the diagnosis.