A nosocomial infection is an infection that is caused by staying in a hospital. An infection is considered nosocomial if it occurs 48 hours or more after a hospital admission. The word comes from the Greek word nosokomeion meaning hospital (nosos = disease, komeo = to take care of ). A related term is iatrogenic disease.

In the United States it has been estimated that as many as one hospital patient in ten acquires a nosocomial infection, or 2 million patients a year. Estimates of the annual cost range from $4.5 billion to $11 billion and up. Nosocomial infections contributed to 88,000 deaths in the U.S. in 1995. One third of nosocomial infections are considered preventable. The most common nosocomial infections are of the urinary tract. The second most common are pneumonias.

Nosocomial infections are even more alarming in the 21st century as antibiotic resistance spreads. Reasons why nosocomial infections are so common include:

• Hospitals house large numbers of people who are sick and whose immune systems are often in a weakened state.
• increased use of outpatient treatment means hospital populations are sicker on average.
• medical staff move from patient to patient, providing a way for pathogens to spread.
• many medical procedures bypass the body's natural protective barriers.
• routine use of anti-microbial agents in hospitals creates selection pressure for the emergence of resistant strains.

Thorough hand washing by all medical personnel before each patient contact is one of the most effective ways to combat nosocomial infections. More careful use of anti-microbial agents, such as antibiotics, is also considered vital.

External links

• CDC
• Diseases From Within Our Doors
• Alliance for the Prudent Use of Antibiotics
• WHO - Prevention of hospital-acquired infections