[Hospital infections: sources and routes of infection].

Hospital infections arise by autoinfection from patients' endogenous flora, by cross infection from other patients and hospital staff, and by transmission of pathogens from items in the hospital environment. Organisms may be transmitted by direct and indirect contact, by the airborne route, and with water, food and drugs. This review details the more important routes of infection, highlighting among others the role of Staphylococcus aureus carriage in patients and staff, issues related to disinfection of endoscopes, and the risk of transmitting blood-borne viruses with multidose vials.