 In early 2008, "L. reuteri" was confirmed to be capable of producing reuterin in the gastrointestinal tract, improving its ability to inhibit the growth of "E. coli".The gene cluster controlling the biosynthesis of reuterin and cobalamin in the "L. reuteri" genome is a genomic island acquired from an anomalous source.Although "L. reuteri" occurs naturally in humans, it is not found in all individuals.