Background: Neonatal gut colonization starts immediately after birth. It is affected by mode of delivery, type of infant’s feeds and antibiotics use.
Objective: To identify the bacteria cultured in the stools of term newborn infants, and characterize associations to mode of delivery and type of infant’s feeds.
Methods: 32 newborns (birth-weight 3351±616 g, gestational age 39.2±1.4 weeks) were included. 43 stool cultures collected on day of life 1.3±0.6. In 11 (34.4%) newborns there was no growth, in 18 (56.2%) E.Coli grew, and only in 3 (9.4%) there was growth of Lactobacilli. Of the 5 infants fed breast milk only: 2 had no growth, 2 grew Lactobacilli and 1 – E.Coli. Of the 8 fed formula only: 4 had no growth, 1 grew Lactobacilli and 3 had E.Coli. Of the 19 fed on breast milk and formula: 5 had no growth and 14 grew E.Coli (Chi sqiare=10.53, p=0.032). In a multi-variate model breast milk feeding only (as opposed to formula or mixed feedings) was associated with increased chance of no growth or lactobacillus growth in feces (OR=10.74; 95% CI 0.92-125.68, p=0.040); cesarean delivery (as opposed to vaginal) concomitantly increased the chance for no growth or Lactobacillus (OR=5.09; 95% CI 0.96-25.90, p=0.052). Combined model of human milk and cesarean delivery was significant (p=0.027).
Conclusions: Human milk feeding after delivery inhibits normal fecal flora growth and encourages probiotic bacterial growth. Cesarean delivery without passage through the birth canal might contribute to this.
Key words: stools; newborns; Lactobacilli, E.Coli; breast milk; mode of delivery.