Antibiotics and baby’s bugs — what effects have antibiotics on the bacteria present in the infant gut?

Take a moment to consider that there are ten times more bacteria present in the human gut than there are human cells in the body. Surprising and shocking as this may be, it should also occur to you that such vast numbers of bacteria are not there just by chance. In fact, these populations play numerous vital roles in our health and daily functioning. There are at least 100 trillion bacterial cells in the human gut, comprising over 500 different types, and these bacteria are involved in diverse and vital roles such as the digestion of foods, including foods which we would otherwise be unable to metabolise due to a lack of appropriate enzymes. These gut bacteria also contribute to the development of the gutassociated lymphoid tissue (GALT; part of the immune system located in the gut which is vital for developing tolerance to beneficial bacteria). Additionally, these gut bacteria synthesize vitamins (B and K) and aid in the elimination of harmful toxins.