[Bacterial biofilms and resistance to disinfectants].

When bacteria grow in close association with solid surface, they constitute a microbial community tight included in the exopolymer glycocalyx. Many laboratory studies have shown that these bacteria are 10 to 100 folds more resistant to disinfectants than the bacteria of the same strain in suspension. Several factors are responsible for this resistance: the glycocalyx which limits the diffusion and reacts with the disinfectant, the more or less dense repartition of the bacteria inside the biofilm, their physiologic state with reduced metabolism, and the surface on which is the biofilm. The activity assessment of disinfectant agents is achieved with standardized methods. They must take into account not only the conditions in which the disinfectants are employed, but also the micro-organism state. Experimental results showing the resistance of biofilm bacteria must lead to elaborate methods allowing the assessment of bactericide activity of disinfectants against biofilm bacteria.