ABSTRACTLactic acid bacteria, especially lactobacilli, are common inhabitants of the gastrointestinal tract of mammals, for which they have received considerable attention due to their putative health-promoting properties. In this study, we describe the development and application of luciferase-expressingLactobacillus plantarumandLactococcus lactisstrains for noninvasivein vivomonitoring in the digestive tract of mice. We report for the first time the functionalin vitroexpression inLactobacillus plantarumNCIMB8826 and inLactococcus lactisMG1363 of the click beetle luciferase (CBluc), as well asGaussiaand bacterial luciferases, using a combination of vectors, promoters, and codon-optimized genes. We demonstrate that a CBluc construction is the best-performing luciferase system for the noninvasivein vivodetection of lactic acid bacteria after oral administration. The persistence and viability of both strains was studied by bioluminescence imaging in anesthetized mice and in mouse feces.In vivobioluminescence imaging confirmed that after a single or multiple oral administrations,L. lactishas shorter survival times in the mouse gastrointestinal tract thanL. plantarum, and it also revealed the precise gut compartments where both strains persisted. The application of luciferase-labeled bacteria has significant potential to allow thein vivoandex vivostudy of the interactions of lactic acid bacteria with their mammalian host.
Pharmacokinetics of Lactobacillus plantarum
NCIMB 8826, Lactobacillus fermentum
KLD, and Lactococcus lactis
MG 1363 in the human gastrointestinal tract
