Effects of the consumption of heat-killed Enterococcus faecalis EC-12 preparation on microbiota and metabolic activity of the faeces in healthy adults

Abstract

The effects of the consumption (200 mg/day) of heat-killed Enterococcus faecalis EC-12 preparation (EC-12) for 14 days on microbiota and metabolic activity of the faeces were studied in eight healthy volunteers (22–26 years of age). During EC-12 consumption, the counts of bifidobacteria (p<0.05 on day 7 and p<0.01 on day 14) were significantly increased, except for the numbers of bifidobacteria in one volunteer, whereas the counts and the frequency of occurrence of lecithinase-positive clostridia (p<0.05), including Clostridium perfringens, were significantly decreased, when compared with the values before EC-12 consumption and during placebo consumption. The decreased tendency in the counts of Enterobacteriaceae and the increased tendency in the levels of lactobacilli was observed during EC-12 consumption, compared with the values before EC-12 consumption and during placebo consumption. No detectable changes occurred in the counts of other organisms throughout the experimental periods. The total faecal volatile fatty acid and acetic acid (p<0.05 on day 7 and p<0.01 on day 14) during EC-12 consumption, and succinic acid (p<0.05), lactic acid (p<0.05) and propionic acid (p<0.05) on day 14 of EC-12 consumption were significantly increased when compared with the values before EC-12 consumption and during placebo consumption. Faecal concentrations of ammonia, phenol and p-cresol (p<0.05) were significantly decreased on day 14 of EC-12 consumption. Faecal levels of sulfide and indole (p<0.05) were significantly decreased during EC-12 consumption. Faecal values of oxidation-reduction potential (ORP; p<0.05 on day 7 and p<0.01 on day 14) were significantly decreased during EC-12 consumption. Faecal pH values tended to decrease on day 14 of EC-12 consumption. Stool weight and water content were slightly increased during EC-12 consumption. The odour of the faeces was slightly reduced during EC-12 consumption.

• Enterococcus faecalis EC-21
• faecal microbiota
• faecal metabolic products
• heat-killed bacteria