Lactobacillus rhamnosus GG (ATCC53103)

Lactobacillus rhamnosus GG (ATCC 53103, also known as LGG), is a strain of L. rhamnosus and is one of the most well-known probiotics strains. It was isolated in 1983 from the intestinal tract of a healthy human being by Barry R. Goldin and Sherwood L. Gorbach^​1​.

LGG has several features that distinguish it from other probiotics strains; First, LGG is highly acid-resistant, which gives it the ability to survive the acids and bile of the human stomach and intestine^​3​. Furthermore, LGG strains could adhere to mucosal structure and colonize the intestine^​4​, and exclude or reduce pathogenic adherence in a way to produce compounds antagonistic to pathogen growth^​5​. All these properties make LGG a particularly remarkable probiotic strain.

These characteristics have led to extensive research on the prevention and treatment of various diseases that eventually caused the strain to become known as the world’s most-studied bacteria. The first commercial use of probiotics with LGG was launched in Finland in 1990 under the Valio Gefilus® brand. Currently, LGG is the most representative probiotic strain of Chr. Hansen.

How was the safety of LGG evaluated? As the popularity of LGG increased followed by its consumption, the possibility of side effects caused by the bacterial infection increased. However, this Lactobacillus bacteremia issue that can be induced from this specific probiotic strain was resolved by Finnish surveillance data over the decade from 1990 to 2000^​6​.

There are hundreds of studies that support LGG being clinically effective. Many researchers set up LGG-treated groups and placebo-controlled groups to check to see if symptoms had been significantly improved, and numerous clinical trials had confirmed its incidence of diarrhea, atopic eczema, and respiratory infections. Much more efficacy of LGG such as the regulation of the immune responses and obesity prevention is being reported continuously^​7–14​.

The genome of LGG strain was also investigated to reveal its genetic properties. Kankainena et al., 2009 found that LGG has 143 unique proteins compared to other strains, of which 24 proteins were related to carbohydrate transport and metabolism. It is reported that these unique proteins allow LGG to utilize monosaccharides and disaccharides as a substrate for metabolic activities in the small intestine rich in carbohydrates. These features might help LGG strains colonize the small intestine readily. The author also found that mucous membrane properties of LGG were due to protein-mediated strain-specific ability through the previous studies about LGG to adhere to intestines is thought to be sensitive to protease. Furthermore, this study has shown amazing results that spaC has an essential role in the interaction of LGG strains with mucous membranes and explains its ability to persist in the human intestinal.

LGG has unique characteristics and strengths compared to other probiotics, and its effect on health improvement has been proven clinically. As existing technologies are continuously being updated and new technologies are being invented to use on a huge commercial scale, we hope more LGG-like probiotics will soon be isolated, characterized and refined to use in the prevention and treatment of other significant diseases.