Effects of feeding an infant formula containing lactobacillus GG on the colonization of the intestine - A dose-response study in healthy infants

Objectives: This study aimed to determine whether feeding Lactobacillus GG (LGG) at varying levels (10(8) to 10(10) cfd/day) would result in colonization. defined as >= 1,000 cfu of LGG per gram of stool in 3 of 5 samples collected during the feeding period. Methods: Infants received unsupplemented formula during a 7-day baselines 1 of 4 formulas containing 0 (control), 10(8) (low), 10(9) (medium), or 10(10) (high) cfu of LGG per day during a 2-week test, and unsupplemented formula during a 2-week follow-up. Baseline, test, and follow-tip stool samples were evaluated for levels of viable LGG. Results: During test, supplemented infants were colonized, compared with control (P < 0.05). Median stool counts of LGG (log(10) cfu/g) in colonized infants were 5.24 (low), 6.05 (medium), and 5.97 (high). LGG persisted in the stools for 7 to 14 days after discontinuing LGG. No differences were observed among groups in stool consistency, flatulence, fussiness, or adverse events. Conclusion: A 2-week oral administration of 10(8) to 10(10) cfu/day LGG was well tolerated; all levels successfully colonized the intestinal tract of healthy, term infants.