Transcellular transport is not required for transmucosal bacterial passage across the intestinal membrane ex vivo

The mechanisms underlying the process of bacterial translocation are poorly defined. Possible routes for transmucosal passage of bacteria include transcellular and paracellular channels. Bacterial engulfment is a prerequisite for transcellular transport. To determine whether transcellular transport is required for transmucosal bacterial passage, we examined the effect of various inhibitors of endocytosis, such as colchicine, cytochalasin B, and sodium fluoride on transmucosal passage of bacteria across an ileal mucosal membrane mounted in the Ussing chamber. Colchicine and sodium fluoride increased the rate of decline of the potential difference across the membranes. However, neither colchicine, cytochalasin B, nor sodium fluoride affected the incidence of transmucosal bacterial passage. Sodium fluoride, which depletes intracellular ATP, significantly decreased the number of bacteria that passed per membrane. Our data suggest that transcellular transport may not be required for spontaneous transmucosal passage of bacteria, and furthermore bacterial passage may be, at least in part, an energy-dependent process.