Modulation of intestinal microbiota in mice by kefir administration

Kefir is a multi-species probiotic consisting of lactic and acetic acid bacteria and yeast. The modulatory effects of kefir on gut microfloral profiles of mice were investigated using group-specific quantitative real-time polymerase chain reaction. At the end of 3 week oral kefir administration period, the numbers of Firmicutes, Proteobacteria, and Enterobacteriaceae were significantly (p < 0.05) decreased, and the numbers of Bacteroidetes, Lactobacillus, and Lactococcus, and total yeast were significantly (p < 0.05) increased in the kefir group, compared with the control group. Kefir consumption significantly (p < 0.05) suppressed proliferation of the opportunistic pathogen Enterobacteriaceae, compared with saline administration, with an increased proportion of Lactobacillus and Lactococcus to total bacteria, suggesting lactobacilli-Enterobacteriaceae antagonism. Kefir consumption significantly (p < 0.05) reduced the Firmicutes/Bacteroidetes (F/B) ratio, compared with controls, suggesting oral administration of kefir could be beneficial in the treatment of obesity.