Nosocomial Infection · What Is It, Causes, Prevention, and More

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. 

• Increasing age

• Greater length of hospitalization

• Excessive or improper use of broad-spectrum antibiotics

• Higher number of invasive devices and procedures (for instance: central venous catheters, urinary catheters, surgical procedures, and mechanical ventilation) 

• Comorbid conditions

  • Diabetes

  • Chronic lung disease

  • Renal insufficiency

  • Malnutrition

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

  • Ventilator-associated pneumonia is a respiratory infection caused by breathing in contaminated oropharyngeal flora during mechanical ventilation (machine-assisted breathing). 

    • Together with central-line bloodstream infections, it is the third most common nosocomial infection. 

    • Early-onset nosocomial pneumonia occurs within the first four days of admission and is commonly caused by community-acquired pathogens like Staphylococcus aureus, Streptococcus pneumoniae, and Haemophilus influenzae. 

    • Late-onset pneumonia is frequently caused by multi-drug resistant bacteria like MRSA, Pseudomonas aeruginosa, Klebsiella, and Acinetobacter. 

    • Signs and symptoms include fever, increased mucus production, increased white blood cell count, and abnormal chest X-ray findings.

• 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