A hospital-acquired infection is usually one that first appears three days after a patient is admitted to a hospital or other health-care facility. Such infections are also called nosocomial infections.

About 5-10% of patients admitted to hospitals in the United States develop one of these infections, which are usually related to a procedure or treatment used to treat the patient.

Hospital-acquired infections can be caused by bacteria, viruses, fungi, or parasites. These microorganisms may already be present in the patient's body or may come from the environment, contaminated hospital equipment, healthcare workers, or other patients. An infection may start in any part of the body. A localized infection, such as at an abdominal surgery site, is limited to a specific part of the body and has local symptoms. A generalized infection enters the bloodstream and causes general systemic symptoms such as fever, chills, low blood pressure...