Fig. 6

Intranasally applied E. coli Nissle transiently migrates in lungs and gut. Spatial and temporal transit of E. coli Nissle was analyzed using the in vivo imaging system (IVIS). L. plantarum was used as control strain. a Schematic representation of the application of EcN-CBRluc and Lp-CBRluc to study migration of bacteria. Female BALB/c mice were treated either orally (5×10¹⁰ CFU/200 µl dose) or intranasally (5×10⁸ CFU/30 µl dose) with either EcN-CBRluc or Lp-CBRluc. Before in vivo imaging at different time-points, 30 mg/ml of d-luciferin potassium salt substrate was intragastrically (200 µl/mouse) administered in the groups of mice treated orally and 15 µl per nostril in the groups of mice treated intranasally. Mice were anesthetized and immediately bioluminescence imaging of mice was performed using IVIS. b Representative in vivo image of one mouse and its digestive tract at 10 min and 2 h after oral application of EcN-CBRluc and Lp-CBRluc. c Representative in vivo image of one mouse and its nose, lungs and gut at 10 min and 2 h after intranasal application of EcN-CBRluc and Lp-CBRluc. Organs were collected after sacrifice, and the bioluminescent signal was quantified on intact organs. The intensity of the transcutaneous photon emission is represented as a pseudocolor image. Data are representative of two independent experiments (n = 6 mice per group). Two mice were sacrificed at each time point. EcN* represents EcN-CBRluc and LP* represents Lp-CBRluc