The altered Schaedler flora (ASF) is a community of eight bacterial species: two Lactobacilli, one Bacteroides, one spiral bacteria of the Flexistipes genus, and four extremely oxygen sensitive (EOS) Fusobacterium species. The bacteria are selected for their dominance and persistence in the normal microflora of mice, and for their ability to be isolated and grown in laboratory settings. Germ-free animals, mainly mice, are infected with ASF for the purpose of studying the gastrointestinal (GI) tract. Intestinal commensal bacteria play an important role in affecting gene expression of the GI tract, immune responses, nutrient absorption, and pathogen resistance. The standardized microbial cocktail enabled the controlled study of microbe and host interactions, role of microbes, pathogen effect