Table 1.

Details of subject groups

Gestational ages at birth (n)All (58)<26 wk (15)26–28 wk (20)>28 wk (23)
Perinatal
 Vaginal birth, n (%)13 (22)4 (27)6 (30)3 (13)
 Birth weight g, median (IQR)960 (800, 1220)750 (690, 900)895 (770, 980)1,250 (1,110, 1,445)
 Gestational age at birth weeks, median (IQR)27.1 (25.6, 29.0)25 (24.9, 25.3)26.7 (26.3, 27.1)29.1 (28.9, 31.6)
 Male/Female24/344/1110/1010/13
 Caucasian/African American30/285/1010/1015/8
 APGAR 5 min, median (IQR)7.0 (6.0, 8.0)6.0 (4.0, 7.0)7.0 (5.5, 8.0)8.0 (6.0, 9.0)
Postnatal
 First antibiotic free day of life, median (IQR)5 (4, 9)5 (4, 9)8.5 (4, 9.5)4 (2, 5)
 Percent of days of life on antibiotics,* median (IQR)14 (5.8, 25.6)22.2 (11.4, 30.6)17.3 (8.6, 29.0)6.4 (5.4, 14.3)
 Day of life on which enteral feedings initiated, median (IQR)5.5 (4.0, 8.0)7.0 (6.0, 9.0)5 (4.0, 7.0)4.0 (3.0, 7.0)
 Human milk use
  None, n (%)2 (3)01 (5)1 (4)
  <10%, n (%)16 (28)4 (27)8 (40)4 (17)
  10–50%, n (%)18 (31)3 (20)4 (20)11 (48)
  >50%, n (%)22 (38)8 (53)7 (35)7 (31)
Outcome
 Discharged to home from NICU, n (%)57 (98)15 (100)19 (95)23 (100)
 Day of life discharged home (IQR)61 (49, 73)78 (75, 81)65 (60, 71)47 (37, 51)
 Days to death (n)66 (1)N/A66 (1)N/A
  • APGAR score, a measure of physical condition at birth scored from 0 to 10, 10 being highest; N/A, not applicable.

  • * Percent of days of life antibiotics were administered before each specimen.

  • Percentage of enteral volume provided by human milk.