Abstract
The digestive microflora is characterized by a high degree of complexity and diversity. Variation in the composition of the digestive flora of an individual occurs in space and time. Two kinds of strains can be defined: transient strains in opposition to resident strains, which are repeatedly isolated from the digestive tract over a long period of time. The latter can be assumed to have colonized the digestive tract. We will present here studies on the properties of bacteria implicated in the colonisation process. Firstly, we summarize data on the role of adherence in this process, the mechanisms involved in adhesion to mucosal structures (cellular and mucus glycoproteins, extracellular matrix components) and give examples of adhesion in various intestinal bacterial groups (commensal and potentially pathogenic bacteria). Secondly, we describe the role of glucidolytic and proteolytic enzymes involved in host-bacteria interactions and implicated in colonisation and maintenance of the indigenous intestinal flora.