Effect of Administration of Lactobacillus casei Strain GG on the Gastrointestinal Microbiota of Newborns

The aim of the study was to determine whether Lactobacillus casei strain GG could colonise the intestine of newborns and the influence of its administration on establishment of the microbiota. The faecal bacterial population of 25 under 1 mth old newborns was studied: in addition to breastfeeding, 15 babies (GG group) received for 2 wk immediately after birth Lactobacillus GG supplement as freeze-dried powder diluted in water in a dose of 1010-1011 c.f.u./g; 10 newborns (control group) did not receive any supplement to breastfeeding. The faecal bacterial composition of meconium was similar in both groups studied. Ten newborns (67 per cent) excreted Lactobacillus GG, while in eight cases (53-3 per cent) Lactobacillus GG was found even 2 wk after the administration was stopped. The faecal concentrations and the relative proportion of Lactobacillus GG were individually different. In 3-4 d, 5-7 d and 1 mth old newborns of the GG group the faecal concentrations of lactobacilli exceeded those of the control group. The faecal microorganisms predominance pattern did not differ in the case of 1 wk and 1 mth old newborns of the GG group. The study shows that 2 wk administration of Lactobacillus GG, which starts right after birth, increases intestinal lactobacilli concentrations and does not impair the establishment of a normal faecal bacterial microbiota.