The acute-care health facility provides all of the needed elements for infection spread - patients with an established illness, health-care personnel who may or may not follow infection control policies, equipment, food, water and microorganisms. Microorganisms include those brought into the health facility by the patient, as well as organisms that are already in existence at the health facility. As health care has changed its mode of operation in recent years, so has the patient population been altered. More individuals are scheduled for procedures as an outpatient. There are fewer in-patient admissions, but the hospitalized patient appears to be older. An increased number of surgical procedures are being performed, such as heart valve replacement, cardiac bypass grafting and orthopedic joint replacement. Immunosuppressive treatment for a condition such as transplant is more widely available.