The effect of probiotic bacteria Lactobacillus acidophilus NCFM and Bifidobacterium
lactis Bi-07 on the composition of the Lactobacillus group, Bifidobacterium and
the total bacterial population in feces from young children with atopic dermatitis
was investigated. The study included 50 children randomized to intake of one of
the probiotic strain or placebo. Microbial composition was characterized by
denaturing gradient gel electrophoresis, quantitative PCR and, in a subset of
subjects, by pyrosequencing of the 16S rRNA gene. The core population of the
Lactobacillus group was identified as Lactobacillus gasseri, Lactobacillus fermentum,
Lactobacillus oris, Leuconostoc mesenteroides, while the bifidobacterial community
included Bifidobacterium adolescentis, Bifidobacterium bifidum, Bifidobacterium
longum and Bifidobacterium catenulatum. The fecal numbers of L. acidophilus and
B. lactis increased significantly after intervention, indicating survival of the
ingested bacteria. The levels of Bifidobacterium correlated positively (P = 0.03),
while the levels of the Lactobacillus group negatively (P = 0.01) with improvement
of atopic eczema evaluated by the Severity Scoring of Atopic Dermatitis index. This
correlation was observed across the whole study cohort and not attributed to the
probiotic intake. The main conclusion of the study is that administration of L.
acidophilus NCFM and B. lactis Bi-07 does not affect the composition and diversity
of the main bacterial populations in feces.