[Protective role of the Doderleïn flora].

The vaginal flora of a healthy woman is composed of the Doderleïn bacilli (different species of lactobacilli) forming a biofilm on the mucosa. These bacteria have a beneficial effect by inhibiting growth, adhesion or spread of other microorganisms. Different mechanisms are recognized, including secretion of organic acids, production of antimicrobial substances (hydrogen peroxide, bacteriocins and biosurfactants), competition for nutrients (arginine deiminase), competition for receptors (adhesion on the epithelium), steric exclusion (biosurfactants, adhesion on the epithelium or on the fibronectin) and co-aggregation. This ecological balance can be disturbed by drugs (antibiotics and spermicides) or by local devices. A new therapeutic approach has been proposed to restore a normal flora: the use of probiotics by the association of different lactobacilli with combined antimicrobial activity.