[General epidemiology of nosocomial infections. Surveillance systems and programs]

Infections related to the health-care system are those associated with health care practices in hospitalized patients as well as in out-patients with health-care contact. Nosocomial infections affect 5% of in-patients, and carry a high morbidity, mortality and economic cost. The main types of nosocomial infections are related to invasive procedures, and include respiratory tract infection, surgical site infections, urinary tract infections, and vascular catheter bacteremia. It has been shown that the application of checklists and a bundle of measures are useful in preventing these infections. Epidemiological surveillance, defined as the gathering of information to take actions, is the basis of infection control programs. These have evolved from a global surveillance targeted at processes and indicators of nosocomial infection. The comparison of these indicators can be useful in establishing preventive measures.