1. The use of probiotic bacteria in the manufacture of a medicinal product or therapeutic nutritional composition to increase during the first four months of life the secretion of IgA in infants born by cesarean section. ! 2. The use of probiotic bacteria in the manufacture of a medicinal product or therapeutic nutritional composition to increase during the first four months of life the immune defense of the mucosa in babies born by cesarean section. ! 3. The use according to any one of claims 1 or 2, wherein the probiotic bacteria are lactic acid bacteria. ! 4. The use according to claim 3, where the lactic acid bacteria are strains of Lactobacillus rhamnosus CGMCC 1.3724, Lactobacillus reuteri ATCC 55730, Lactobacillus reuteri DSM 17938, Lactobacillus fermentum VRI 003 or Lactobacillus paramenti CNCM 1-2116. ! 5. The use according to any one of claims 1 or 2, wherein the probiotic bacteria are bifidobacteria. ! 6. The use according to claim 5, where the bifidobacteria are strains of Bifidobacterium lactis CNCM 1-3446, Bifidobacterium longum ATCC BAA-999, Bifidobacterium breve Bb-03, Bifidobacterium breve M-16V or Bifidobacterium breve R0070. ! 7. The use according to claim 1 or 6, where the drug or therapeutic nutritional composition further comprises a mixture of galactooligosaccharide (s), N-acetylated oligosaccharide (s) and sialylated oligosaccharide (s), in which the N-acetylated oligosaccharide (s) is from 0.5 to 4.0% of the oligosaccharide mixture, galactooligosaccharide (s) is from 92% to 98.5% of the oligosaccharide mixture and sialylated oligosaccharide (s) is from 1.0 to 4.0% of the oligosaccharide mixture. ! 8. The use according to claim 1 or 6, where the drug or therapeutic nutritional composition is administered to the infant immediately after birth, and then for at least 2 months1. Применение пробиотических бактерий при производстве лекарственного средства или терапевтической питательной композиции для увеличения в течение первых четырех месяцев жиз