Nosocomial infections are acquired by patients while in health care facilities such as hospitals and clinics.  Nosocomial diseases are among some of the most common and costly medical problems today, accounting for ~90,000 deaths annually in the United States alone.

Exogenous nosocomial infections are the result of pathogens being spread by patients as they are shed from various portals of exit while the patients are in the health care facility.

Endogenous nosocomial infections are the result of opportunistic pathogens already present in or on the body of the patient and brought on by conditions present at or the direct result of activities at the health care facility.

Iatrogenic nosocomial infections are spread by health care workers, generally as the result improper sanitary conditions, failure to follow universal precautions, or contaminated invasive surgical or patient care equipment.

This graphic represents the interplay of factors resulting in nosocomial infections.  Those these infections can be the result of any one of the causes shown here, when all interact the likelihood of nosocomial infection increases substantially.

Reduction in nosocomial infection requires conscious effort to maintain good antiseptic and aseptic conditions and techniques, the following of universal precautions such as wearing gloves and changing gloves and washing hands between patients, never handling any sterile apparatus that might contact patient skin, proper disposal of biohazardous materials, isolation of contagious and susceptible patients and regular sanitation of hospital garments.  The establishment of infection control committees and officers should also be considered an important step in finding and eliminating the root causes of such infections.