.png){kind=icon}
1. Microbial succession is the term used to describe the fact that different organisms become established as part of the normal flora at different stages of development. Formula-fed infants do not go through the second phase where Bifidobacterium predominates and their flora resembles that of an older, weaned, breast-fed child.
2. The stomach contains very few bacteria due to the gastric acid, and those that are present are acid-tolerant. The large intestine contains around 1011 bacteria per gram of contents, with over 400 species represented, the majority of which are anaerobes.
3. The normal flora protect the host from disease by competitive adherence to the epithelial cells, production of antimicrobial substances, competition for nutrients, stimulation of peristalsis and by the creation of conditions unfavourable for non-native organisms.
4. The effects of antibiotics on normal flora may persist for four weeks and render the individual more susceptible to infection by pathogens such as Salmonella, as well as to the development of antibiotic-associated diarrhoea which is frequently caused by Clostridium difficile.
5. Three important benefits of probiotic and prebiotic supplements are the prevention and reduction in duration of rotavirus diarrhoea, the induction of remission in inflammatory bowel disease, and the lowering of serum cholesterol by reduced absorption of lipids.