TABLE 1

Infant characteristics

CharacteristicValue for infants who:
Received no antibiotics
after the first week
Received antibiotics
after the first weeka
No. of samples604298
Total no. of infantsb7136
No. of infants who received breast milk5232
No. of infants who were delivered by C-section5422
No. of infants of male sex3417
No. of infants with maternal antibiotics2420
  • a The infants represented in the column corresponding to those who received antibiotics after the first week (right) were administered antibiotics while in the NICU beyond the first week of life due to late-onset sepsis, necrotizing enterocolitis, or another disease.

  • b All 107 premature infants were in the neonatal intensive care unit (NICU) of the Magee-Women’s Hospital in Pittsburgh, PA.