[Effect of antibiotics on bacterial adherence to foreign material]

Microbial adherence is the first step of foreign body infection. In vitro and ex vivo experiments have studied the mechanisms of the anti-adherent effect of antimicrobial agents. Adherence of bacteria onto foreign bodies is a complex phenomenon where several factors from the bacteria, the foreign body and the host, are involved. Bacterial factors are physicochemical factors such as cell surface charges, hydrophobicity, and adhesins such as exopolysaccharides or "slime". Foreign body factors are irregularities of the surface and hydrophobicity. Human factors are serum proteins as fibronectin, collagen, laminin and vitronectin, which are deposited onto the material and act as receptors for bacteria. In vitro models can study the interactions between the bacteria, the foreign body and the antimicrobial agent. They can be useful to analyse the molecular mechanisms of the effects of the antimicrobial agents on microbial adherence. Different studies have shown: 1) no relation between the effect of antimicrobial agents on microbial adherence and their bacteriostatic or bactericidal effects, 2) antimicrobial agents of the same class may have different effects on the same strain, 3) no correlation between effect of antimicrobial agents on microbial hydrophobicity, slime production or fibronectin receptors, and effect on adherence.