Survival of Lactobacillus helveticus strain CP53 in the human gastrointestinal tract

A strain of Lactobacillus helveticus carrying the cryptic plasmid pCP53 was used for a detailed analysis of the survival and persistence of this organism in the faeces of volunteers administered oral doses of the strain. The CP53 strain had high affinity for Caco-2 cells, but displayed low bile acid resistance in vitro. Rifampicin-resistant colonies could be reisolated from the faeces of four of seven subjects fed with the rifampicin-resistant CP53 derivative strain. Moreover, the recovery of cells, as estimated by plasmid analysis, was higher than that estimated by measuring the number of rifampicin-resistant cells. From these results, we conclude that the CP53 strain can survive passage through the gastrointestinal tract.