Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
9282879 | Microbes and Infection | 2005 | 7 Pages |
Abstract
Lactobacillus colonisation was examined in 112 Swedish infants. Faecal samples obtained at 1, 2, 4 and 8Â weeks and at 6, 12 and 18Â months of age were cultivated quantitatively on Rogosa agar. Lactobacilli were speciated by PCR and typed to the strain level by randomly amplified polymorphic DNA (RAPD). Lactobacilli reached a peak at 6Â months when 45% of the infants were colonised. L. rhamnosus and L. gasseri were the most common species in this period. Colonisation by lactobacilli in general (PÂ <Â 0.01) and L. rhamnosus in particular (PÂ <Â 0.05) was more common in breast-fed than in weaned infants at 6Â months of age. Lactobacillus isolation reached a nadir of 17% by 12Â months (PÂ <Â 0.0001), but increased to 31% by 18Â months of age PÂ <Â 0.05). The food-related species L. paracasei, L. plantarum, L. acidophilus and L. delbrueckii dominated in this second phase. A single strain persisted for at least 3Â weeks in 17% of the infants during the first 6Â months, most commonly L. rhamnosus. Lactobacillus population counts in colonised infants increased from 106.4Â cfu/g at 1Â week to 108.8Â cfu/g at 6Â months, and then dropped to 105.4Â cfu/g faeces at 12Â months of age. Lactobacillus colonisation was not significantly related to delivery mode, or to presence of siblings or pets in the household. Our results suggest that certain Lactobacillus species, especially L. rhamnosus, thrive in the intestinal flora of breast-fed infants. After weaning they are replaced by other Lactobacillus species of types found in food.
Related Topics
Life Sciences
Immunology and Microbiology
Immunology
Authors
Siv Ahrné, Elisabet Lönnermark, Agnes E. Wold, Nils Ã
berg, Bill Hesselmar, Robert Saalman, Inga-Lisa StrannegÃ¥rd, Göran Molin, Ingegerd Adlerberth,