Probiotic consumption is known to influence the composition of intestinal microbiota by significantly
increasing
the counts of the target probiotic strains. However it is still unknown whether other bacterial
indicators
of the fecal microbiota are affected. In this study, two culture-independent molecular
methods
were used to profile the fecal microbiota of healthy human adult subjects: Terminal restriction
fragment
length polymorphism (T-RFLP) and quantitative PCR (qPCR). The impact of probiotic intake on
bacterial
community profile as well as effect on the variation of some indicator fecal microbiota species
were
assessed on fecal DNA samples obtained during the clinical trial of a commercial yogurt. T-RFLP of
fecal
samples showed no difference in profile variation between placebo or yogurt consumption (Bray–
Curtis
distance). Quantification by qPCR of some elements of fecal populations and endogenous
Bifidobacterium
species revealed that beyond the increase in probiotic species (Bifidobacterium animalis
subsp.
lactis and Lactobacillus acidophilus LA-5), the variations observed were largely due to inter-subject
variation
rather than treatment effect. The molecular profile of the fecal microbiota of healthy adults is
not
disturbed by commercial probiotic yogurt consumption despite a strong presence of the probiotic
strains.