The term "resident" comes from Latin and means "to settle down". Resident bacteria are microorganisms that have settled in the microbiome over a long period of time. So they have “settled” in the gut and stay there.
Transient (- Latin transire = to pass by) bacterial strains, on the other hand, are organisms that do not settle in the microbiome. They are "in transit" and are simply excreted from the body.
However, probiotics do not have to colonize the intestine to be effective!
Scientists have found that probiotics exert their effects predominantly as transient bacteria . They travel through the digestive tract, interacting with your immune cells, gut cells, nutrients, and bacteria present along the way to provide direct and indirect benefits. Some enhance gene expressions in signaling the tight junctions that help protect against gut permeability—meaning a tight gut barrier. The intestinal barrier decides which substances from the digestive tract can enter the body through the intestinal wall. A healthy intestinal barrier is a protective wall that makes it harder for pathogenic substances and harmful bacteria to penetrate the body through the intestinal wall - this in turn has a positive effect on your immune system.
Other transient bacteria promote the release of neurotransmitters that stimulate muscle contractions for increased motility, leading to better and more regular bowel movements. If the intestine moves regularly, food can be transported better and symptoms such as constipation can be avoided. There are also bacteria that produce by-products like short-chain fatty acids that are beneficial for metabolic and gut health.
However, since the transient bacteria are excreted at the end of their journey through our intestines, continuous intake is important. Therefore, probiotics only develop their best effect on health if they are taken over a long period of time. To make this easier, we have a subscription - your Dailybacs come to your home conveniently every 30 days.