Effect of feeding of a cholesterol-reducing bacterium, Eubacterium coprostanoligenes, to germ-free mice.

Twelve germ-free mice were used to evaluate the effect of orally administered Eubacterium coprostanoligenes (ATCC 51222) on serum cholesterol concentration. After 1 week of bacterial administration, serum cholesterol concentration of the experimental group (204.9 +/- 5.3 mg/dl, mean +/- SEM) tended to be lower than that of controls (213.7 +/- 5.9 mg/dl, mean +/- SEM). The hypocholesterolemic effect, however, was transient. Greater coprostanol-to-cholesterol ratios in feces of bacteria-fed mice also indicated a transient cholesterol-reducing action of E. coprostanoligenes in the intestine. Eubacterium coprostanoligenes did not colonize the intestine of E. coprostanoligenes-fed mice. Results indicate that the transient occurrence of E. coprostanoligenes in the digestive tract of E. coprostanoligenes-fed mice may decrease plasma cholesterol concentration, but colonization of the tract depends on monoassociation with another bacterium. Results also indicate that feeding of E. coprostanoligenes decreases blood cholesterol concentration.