Nosocomial Infection

What Is It, Causes, Prevention, and More

Author: Jennifer Cheung, RN

Editors: Antonella Melani, MD,Ahaana Singh,Lisa Miklush, PhD, RN, CNS

Illustrator: Abbey Richard

Modified: 20 Jul 2021

What is a nosocomial infection?

Nosocomial infections, also called health-care-associated or hospital-acquired infections, are a subset of infectious diseases acquired in a health-care facility. To be considered nosocomial, the infection cannot be present at admission; rather, it must develop at least 48 hours after admission. These infections can lead to serious problems like sepsis and even death. 

Often, nosocomial infections are caused by multidrug-resistant pathogens acquired via invasive procedures, excessive or improper antibiotic use, and not following infection control and prevention procedures. In fact, many nosocomial infections are preventable through guidance issued by national public health institutes such as the Centers for Disease Control and Prevention (CDC). 

Who is at risk for a nosocomial infection?

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What is the most common type of nosocomial infection?

Though various bacteria, viruses, and fungi can all cause nosocomial infections, the most common is the bacterium Staphylococcus aureus. Other common pathogens like Escherichia coli, Enterococci, and Candida are common culprits, and all can be normally found on the skin and mucous membranes. Antibiotic-resistant strains such as methicillin-resistant Staphylococcus aureus (MRSA) can be especially dangerous and difficult to treat.

  • Urinary catheters

    • A urinary catheter is a tube inserted into the bladder to collect urine into a closed collection system. Urinary catheters can help patients who have difficulty controlling or emptying their bladder. As patients under anesthesia are unable to control their bladder, urinary catheters are typically placed during surgical procedures to keep the bladder empty.

    • Pathogens spread through an individual’s perineum or a contaminated urinary catheter can lead to urinary tract infections, which are the most common nosocomial infections

      • Symptoms of urinary tract infections include painful urination, flank pain, and fever.

  • Surgical procedures

    • Surgical site infections are the second most common type that can develop after surgery. 

      • Length of operation, surgical technique, and operating room sterility are all factors that can affect the incidence of surgical site nosocomial infections.

    • Surgical site infections are caused by pathogens already prevalent on the skin or by organisms shed from members of the operating room staff, and often involve the skin, organs, or implanted materials. 

      • Symptoms may include skin redness, tenderness, and drainage from surgical sites.

  • Central venous catheters

    • A central venous catheter (also known as a central line) is a tube placed in a large vein in the neck, arm, chest, or groin and can remain in place indefinitely. Central venous catheters can be used to give intravenous therapies such as total parenteral nutrition (TPN), which provides nutrients and fluids to patients. 

    • Bloodstream infections can result from pathogens that may penetrate the skin during insertion of hubs of central lines. This is the third most common form of nosocomial infection and has the highest rate of mortality

      • Symptoms of infection may include skin redness, tenderness, and drainage at insertion sites.

  • Mechanical ventilation

How can nosocomial infections be prevented?

  • Implementation of  infection control protocols to reduce exogenous and endogenous transmission in health-care facilities. 

  • Exogenous transmission occurs due to person-to-person interactions and through environmental cross-contamination. 

    • Frequent hand hygiene is the most important preventative measure to limit the spread of pathogens. 

    • Compliance with isolation precautions 

    • Proper use of personal protective equipment 

    • Avoidance of unnecessary use of indwelling devices, and remove them as soon as advisable. 

    • Practicing proper aseptic and/or sterile techniques during insertion and maintenance of devices. 

      • Routine disinfection of surfaces, patient equipment, and medical devices

      • Appropriate waste management

  • Endogenous transmission 

    • From excessive and improper use of broad-spectrum antibiotics. 

      • Vancomycin affects the normal balance in the patient's own endogenous bacterial flora, ultimately leading to an overgrowth of some bacteria

      • Appropriate antimicrobial use with the correct agent, dose, and duration is needed to minimize the growth of antibiotic-resistant pathogens 

    • Transfer from one part of the body to the other (as with urinary tract infections)

    • Depressed immune system from factors like malnourishment or chemotherapy 

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Related links

High Yield: Pneumonia
Clinical Reasoning: Pneumonia
Staphylococcus aureus
Pseudomonas aeruginosa
Klebsiella pneumoniae
Streptococcus pneumoniae
Knowledge Shot: Hand Washing

Resources for research and reference

Anderson, D. J., Podgorny, K., et al. (2014). Strategies to Prevent Surgical Site Infections in Acute Care Hospitals: 2014 Update. (2014). Infection Control and Hospital Epidemiology, 35(6): 605–627. DOI: 10.1086/676022

Jameson, J. L., Fauci, A. S., Kasper, D. L., Hauser, S. L., Longo, D. L., & Loscalzo, J. (2018). Harrison’s Principles of Internal Medicine (20 edition). New York, NY: McGraw-Hill.

Klompas, M., Branson, R., et al. (2014). Strategies to Prevent Ventilator-Associated Pneumonia in Acute Care Hospitals: 2014 Update. (2014). Infection Control and Hospital Epidemiology, 35(8): 915–936. DOI: 10.1086/677144

Lo, E., Nicolle, L. E., et al. (2014). Strategies to Prevent Catheter-Associated Urinary Tract Infections in Acute Care Hospitals: 2014 Update. Infection Control and Hospital Epidemiology, 35(5): 464–479. DOI: 10.1086/675718

Marschall, J., Mermel, L. A., et al. (2014) Strategies to Prevent Central Line-Associated Bloodstream Infections in Acute Care Hospitals: 2014 Update. Infection Control and Hospital Epidemiology, 35(7): 753–771. DOI: 10.1086/676533

Papadakis, M. A. & McPhee, S. J. (2020). Current Medical Diagnosis and Treatment (59 edition). New York, NY: McGraw-Hill.

Potter, P. A., Perry, A. G., Stockert, P. A., & Hall, A. M. (2012). Fundamentals of Nursing (8 edition). St. Louis, MO: Elsevier.

Prevention of hospital-acquired infections: A practical guide 2nd edition. (2002). In World Health Organization. Retrieved August 22, 2020, from