Hospital-Acquired Infections | Definition and Patient Education

What Are Nosocomial Infections?

Infections caught in the hospital

A nosocomial infection is contracted because of an infection or toxin that exists in a certain location, such as a hospital. People now use nosocomial infections interchangeably with the terms health-care associated infections (HAIs) and hospital-acquired infections. For a HAI, the infection must not be present before someone has been under medical care.

One of the most common wards where HAIs occur is the intensive care unit (ICU), where doctors treat serious diseases. About one in ten of the people admitted to a hospital will contract a HAI. They’re also associated with significant morbidity, mortality, and hospital costs.

As medical care becomes more complex and antibiotic resistance increases, the cases of HAIs will grow. The good news is that HAIs can be prevented in a lot of healthcare situations. Read on to learn more about HAIs and what they may mean for you.

What are symptoms of nosocomial infections?


For a HAI, the infection must occur:

  • up to 48 hours after hospital admission
  • up to 3 days after discharge
  • up to 30 days after an operation
  • in a healthcare facility when someone was admitted for reasons other than the infection

Symptoms of HAIs will vary by type. The most common types of HAIs are:

  • urinary tract infections (UTIs)
  • surgical site infections
  • gastroenteritis
  • meningitis
  • pneumonia

The symptoms for these infections may include:

  • discharge from a wound
  • fever
  • cough, shortness of breathing
  • burning with urination or difficulty urinating
  • headache
  • nausea, vomiting, diarrhea

People who develop new symptoms during their stay may also experience pain and irritation at the infection site. Many will experience visible symptoms.

What causes nosocomial infections?


Bacteria, fungus, and viruses can cause HAIs. Bacteria alone cause about 90 percent of these cases. Many people have compromised immune systems during their hospital stay, so they’re more likely to contract an infection. Some of the common bacteria that are responsible for HAIs are:

BacteriaInfection type
Staphylococcus aureus (S. aureus)blood
Escherichia coli (E. coli)UTI
Enterococciblood, UTI, wound
Pseudomonas aeruginosa (P. aeruginosa)kidney, UTI, respiratory

Of the HAIs, P. aeruginosa accounts for 11 percent and has a high mortality and morbidity rate.

Bacteria, fungi, and viruses spread mainly through person-to-person contact. This includes unclean hands, and medical instruments such as catheters, respiratory machines, and other hospital tools. HAI cases also increase when there’s excessive and improper use of antibiotics. This can lead to bacteria that are resistant to multiple antibiotics. 

Who is at risk for nosocomial infections?

Risk Factors

Anyone admitted to a healthcare facility is at risk for contracting a HAI. For some bacteria, your risks may also depend on:

  • your hospital roommate
  • age, especially if you’re more than 70 years old
  • how long you’ve been using antibiotics
  • whether or not you have a urinary catheter
  • prolonged ICU stay
  • if you’ve been in a coma
  • if you’ve experienced shock
  • any trauma you’ve experienced
  • your compromised immune system

Your risk also increases if you’re admitted to the ICU. The chance of contracting a HAI in pediatric ICUs is 6.1 to 29.6 percent. A study found that nearly 11 percent of roughly 300 people who underwent operations contracted a HAI. Contaminated areas can increase your risk for HAIs by almost 10 percent.

HAIs are also more common in developing countries. Studies show that five to 10 percent of hospitalizations in Europe and North America result in HAIs. In areas such as Latin America, Sub-Saharan Africa, and Asia, it’s more than 40 percent.

How are nosocomial infections diagnosed?


Many doctors can diagnose a HAI by sight and symptoms alone. Inflammation and/or a rash at the site of infection can also be an indication. Infections prior to your stay that become complicated don’t count as HAIs. But you should still tell your doctor if any new symptoms appear during your stay.

You also may be required to talk a blood and urine test as to identify the infection.

How are nosocomial infections treated?


Treatments for these infections depend on the infection type. Your doctor will likely recommend antibiotics and bed rest. Also, they’ll remove any foreign devices such as catheters as soon as medically appropriate.

To encourage a natural healing process and prevent dehydration, your doctor will encourage a healthy diet, fluid intake, and rest.

What is the outlook for nosocomial infections?


Early detection and treatment are vital for HAIs. Many people are able to make a full recovery with treatment. But people who get HAIs usually spend 2.5 times longer in the hospital.

In some cases, a HAI can seriously increase your risk for life-threatening situations. The Centers for Disease Control and Prevention (CDC) estimate that around 2 million people contract HAIs. About 100,000 of those cases result in death.

Preventing nosocomial infections


The responsibility of HAI prevention is with the healthcare facility. Hospitals and healthcare staff should follow the recommended guidelines for sterilization and disinfection. Taking steps to prevent HAIs can decrease your risk of contracting them by 70 percent or more. However, due to the nature of healthcare facilities, it’s impossible to eliminate 100 percent of nosocomial infections.

Some general measures for infection control include:

  • Screening the ICU to see if people with HIAs need to be isolated.
  • Identifying the type of isolation needed, which can help to protect others or reduce chances of further infection.
  • Observing hand hygiene, which involves washing hands before and after touching people in the hospital.
  • Wearing appropriate gear, including gloves, gowns, and face protection.
  • Cleaning surfaces properly, with recommended frequency.
  • Making sure rooms are well ventilated.

To reduce the risk of UTIs, your healthcare provider can:

  • Follow the aseptic insertion technique to minimize infection.
  • Insert catheters only when needed and remove when no longer needed.
  • Change catheters or bags only when medically indicated.
  • Make sure the urinary catheter is secured above the thigh and hanging below the bladder for unobstructed urine flow.
  • Keep a closed drainage system.

Talk to your doctor about any concerns you have during a procedure.


Nosocomial infections, or healthcare associated infections occur when a person develops an infection during their time at a healthcare facility. Infections that appear after your hospital stay must meet certain criteria in order for it to qualify as a HAI.

If new symptoms appear within 48 hours of admission, three days after discharge, or 30 days after an operation, talk to your doctor. New inflammation, discharge, or diarrhea could be a symptom of a HAI. Visit the CDC website to see what your state’s healthcare facilities do to prevent HAIs.

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