The authors point out how infection of heterologous prosthesis, widely used in surgery, can be a dramatic event. On the other hand, antibiotic prophylaxis is difficult because of the difference between "in vitro" and "in vivo" activity of many antibiotics, due to the production, by many bacteria, of the so-called glycocalyx. This would allow bacteria to clump and adhere to many surfaces, forming micro-colonies, causing delay in phagocytosis, and reducing the efficacy of antibiotics. On the basis of their, although limited, experience, the authors suggest, for the prophylaxis of prosthesis infection, the use of antibiotics such as clindamycin, able to reduce glycocalyx production.