Lactobacillus rhamnosus

Lactobacillus rhamnosus is a probiotic bacterium that was originally considered to be a subspecies of L. casei, but later genetic research found it to be a species of its own. L. rhamnosus inhibits the growth of most harmful bacteria in the intestine. It is used as a natural preservative in yogurt and other dairy products to extend the shelf life. Some studies have been done on its in vivo effects. While frequently considered a beneficial organism, L. rhamnosus has been discovered to be pathogenic in certain circumstances.

Lactobacillus rhamnosus GG
Lactobacillus rhamnosus GG (LGG) is a strain of L. rhamnosus isolated from the intestinal tract of a healthy human being in 1983, filed for patent on 17 April 1985, by Sherwood Gorbach and Barry Goldin. (The first letters of their last names provided the GG). The patent refers to a strain of "L. acidophilus GG" with American Type Culture Collection (ATCC) Accession No. 53103; the organism was later reclassified as a strain of L. rhamnosus. The patent claims that the LGG strain is acid– and bile–stable, has a high avidity for mucosal cells of the human intestinal tract, and produces lactic acid.

Gorbach and Goldin have published a number of studies of LGG, for instance to demonstrate that LGG tolerates the acid conditions in the stomach and the bile acids in the small intestine. Acting as a probiotic, LGG is claimed to colonize the digestive tract and balance the intestinal microflora. In 2005, LGG was used successfully for the first time to treat gastrointestinal carriage of vancomycin-resistant enterococci (VRE) in renal patients.

LGG is a trademark owned by Valio Ltd. Corporation of Finland who signed an agreement with Gorbach and Goldin that gave Valio exclusive global rights to market the LGG probiotic brand.