Abstrakt
Two groups of human milk samples were tested: The first group (18) originated from mothers with babies without bifidobacteria in their faecal flora (BIF-), the second (43) from mothers with babies with bifidobacteria in their faecal flora (BIF+). The occurrence of bifidobacteria in faeces was tested using cultivation method and FISH.
For the detection of bifidobacteria in milk, the samples were subcultivated in TPY broth with mupirocin and subsequently the fructose-6-phosphate phosphoketolase activity (F6PPK) was determined. Infants of mothers from BIF+ group had high numbers of bifidobacteria (usually higher than 9 log CFU/g) in their faeces.
On the contrary, infants of mothers from BIF- group did not contain detectable amounts of bifidobacteria in their faecal samples. These babies possessed significant amounts of clostridia in their faecal flora.
While 35% of milks from BIF+ group expressed F6PPK activity and therefore contained live bifidobacteria, no bifidobacteria were detected in milks from BIF- group. Number of cultivable bifidobacteria in F6PPK-positive milk varied from 1.60 to 4.10 log CFU/ml.
It could be concluded that human milk is probably not the primary source of bifidobacteria for infants. It seems that bifidobacteria occur in mothers' milks as a consequence of contamination from infant.