Nosocomial Infections

In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024 Jan.


Nosocomial infections also referred to as healthcare-associated infections (HAI), are infection(s) acquired during the process of receiving health care that was not present during the time of admission. They may occur in different areas of healthcare delivery, such as in hospitals, long-term care facilities, and ambulatory settings, and may also appear after discharge. HAIs also include occupational infections that may affect staff.

Infection occurs when pathogen(s) spread to a susceptible patient host. In modern healthcare, invasive procedures and surgery, indwelling medical devices, and prosthetic devices are associated with these infections. The etiology of HAI is based on the source or type of infection and the responsible pathogen, which may be bacterial, viral, or fungal.

HAI is the most common adverse event in health care that affects patient safety. They contribute to significant morbidity, mortality, and financial burden on patients, families, and healthcare systems. The emergence of multi-drug resistant organisms is another complication seen with HAI. HAI affects 3.2% of all hospitalized patients in the United States, 6.5% in the European Union/European Economic Area, and worldwide prevalence is likely much higher. The burden of HAIs worldwide is unknown owing to the lack of surveillance systems for HAIs. However, there has been a great effort by infection prevention and control programs to develop surveillance systems and infection control methods.

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