Epsilon Archive for Student Projects

Abstract

The bacteria in our intestine affect us in many different ways, for example, they protect us
against other harmful microorganisms, produce essential vitamins and they are also though to
affect our immune system. Allergies and other immunological diseases are very common in
developed countries compared with developing countries. This has given rise to the hygiene
hypothesis, which suggests that less exposure to microorganisms increases the risk of
developing immunological diseases. Therefore some bacteria might decrease the risk of
developing allergies. People, living according to an anthroposophic lifestyle have been seen to
have less prevalence of allergies. By living according to this lifestyle they eat lots of
fermented food which sometimes contains bifidobacteria and lactobacilli, have limited use of
antibiotics etc. These characteristics may be important factors why anthroposophic individuals
have less prevalence of developing allergies.
Through this study, lactobacilli and bifidobacteria were analyzed in fecal samples from 16
mothers and their infants to see if there were any similarities between mother and child and if
the infant get colonized with the mothers’ fecal lactobacilli and bifidobacteria. The
anthroposophic lifestyle was also investigated, comparing anthroposophic infants with infants
being sensibilized. The amount of bacteria was calculated by using culturing techniques and
the bacteria were typed through rep-PCR. Sequencing of the 16S rRNA genes was also done
on a few lactobacilli and bifidobacteria to identify which species that were transferred.
The results indicated that the infants did have more bifidobacteria and lactobacilli than their
mother but that there was high variation between the samples. The results from rep-PCR
showed that there occurred transmission from the mother to her infant. But that the infants’
microbiota is very unstable and that these bacteria from the mother only in some cases persist
over time and are able to establish in the infants microbiota. No clear difference was seen
between infants living according to an anthroposophic lifestyle and infants being sensibilized.
The results from the sequencing showed that the species which was the most common
Lactobacillus and Bifidobacterium among the samples were Lactobacillus
rhamnosus/paracasei and Bifidobacterium longum.