Hospital-acquired infections are the most common and severe healthcare-associated complications. They are defined as infections occurring in a patient during their stay in hospital or after discharge, which were not present or incubating at the time of admission. Their spread is linked to the gradual introduction of new health technologies that, on the one hand, ensure the survival of patients at high risk of acquiring infections, but on the other hand allow microorganisms to enter areas of the body that are normally sterile. Another crucial aspect to consider is the emergence of bacterial strains that are resistant to antibiotics, as a result of the widespread use of these drugs for prophylactic or therapeutic purposes.
Healthcare has undergone profound changes in recent years. In the past, healthcare was mainly provided by hospitals, but since the 1990s there has been an increase in the number of patients admitted to hospital in a serious condition (and therefore at high risk of developing hospital-acquired infections) and alternative healthcare options (long-stay residential care homes for elderly people, home care, outpatient care). Hence, the need to extend the concept of hospital-acquired infections to include all healthcare-associated infections (HAIs).