Antibiotic Stewardship and Protection of the Developing Preterm Infant Microbiome

Inclusion Criteria for antibiotic randomization:

1. Infant must be born between the gestational ages of 28 0/7 weeks and 34 6/7 weeks

-AND-

2. Infant must be born at investigator's home institution.

-AND-

3. Infant must be considered to have a low risk of infection by one of the following
criteria:

1. Delivered for maternal indications (Cesarean section or induction of labor for
maternal health, including pre-eclampsia, placental abruption, history of
intrauterine fetal demise (IUFD)/abruption, multiple gestation requiring preterm
delivery, etc) -OR-

2. Delivered due to preterm labor to a mother without the diagnosis of
chorioamnionitis/maternal fever or prolonged rupture of membranes >18 hours

Exclusion Criteria for antibiotic randomization:

1. Signs of clinical illness within the first 3 hours of life:

1. 5-minute Apgar <5

2. Requiring vasoactive drugs

3. Seizures

4. Significant respiratory distress requiring supplemental oxygen >40%

2. Immature:Total (I:T) Ratio of >0.2 on initial complete blood count (CBC)

3. Congenital anomalies, including renal anomalies requiring serum antibiotic level
monitoring

ANY infant born between the gestational ages of 28 0/7 weeks and 34 6/7 weeks who do not
meet inclusion criteria, with parental consent, can participate in the stool analysis only
arm of the study.