Nosocomial infections are infections that develop while a person is receiving medical attention. Examples include pneumonia, urinary tract infections (UTIs) and gastrointestinal (GI) infections.

The person will not have this infection on admission but may acquire it in healthcare settings such as hospitals, ambulances, and long-term care facilities.

Nosocomial infections have different symptoms, diagnoses, treatments, and potential complications.

Common types of this infection include:

This article looks at nosocomial infections in more detail, how they occur, and the types of infections. We also look at risk factors, prevention, and the outlook for these infections.

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Doctors also refer to nosocomial infections as healthcare-associated infections (HAI) and hospital-acquired infections.

They are infections that people acquire while receiving healthcare, after admission. The infection can occur when a pathogen — an organism that can cause disease — spreads to a susceptible host.

According to the Centers for Disease Control and Prevention (CDC), some of the many invasive procedures and devices involved in modern healthcare can contribute to the spread of infection. These techniques and devices include:

The causes of nosocomial infections vary. They depend on the type or source of infection, the pathogen that caused it, and whether the infection is viral, fungal, or bacterial.

Nosocomial infections affect 3.2% of all hospitalized patients in the United States. Antibiotic and multidrug-resistant organisms have led to further complications and greater numbers of these infections. Because of this, there has been a major effort to detect and control them with infection prevention and control programs.

Types of nosocomial infections include:

  • central line-associated bloodstream infections (CLABSI)
  • catheter-associated urinary tract infections (CAUTI)
  • surgical site infections (SSI)
  • ventilator-associated pneumonia (VAP)
  • bacterial
  • fungal
  • viral
  • gastrointestinal

A central line, or a central venous catheter, is a tube or catheter to administer fluids or medication or collect blood for specific medical tests. Doctors typically place it in a large vein in the:

  • chest
  • neck
  • groin

Doctors most often use central lines in intensive care units (ICUs). They access a major vein close to the heart and can remain in place for weeks to months. This means they are more likely to cause a serious infection than other types of intravenous catheters, such as IVs.

A CLABSI is a serious infection that can occur when pathogens, such as viruses or bacteria, enter the bloodstream through the catheter.


The symptoms of a CLABSI vary depending on the type of infection that has entered through the catheter. Someone showing signs of infection requires immediate medical intervention. These include:

  • at the site of the catheter:
    • pain
    • discomfort
    • redness
    • discharge
  • fever and chills
  • signs of inflammation

Diagnosis and treatment

To diagnose CLABSI, a doctor will perform blood tests and check for signs of infection at the site of the catheter insertion and inflammation beyond the insertion site.

To treat CLABSI, a doctor typically removes the catheter and administers antibiotics.

They may also prescribe other appropriate medications, such as antifungal medication, depending on the type of infection. Healthcare professionals may also recommend topical or systemic antimicrobials to treat the area where the catheter enters the body.

Potential complications

CLABSI is serious and can be fatal. The infection can cause severe sickness and increase a person’s time in the hospital.

CLABSI may also lead to sepsis, an extreme response by the immune system to infection, which can damage organs and may be life threatening.

CAUTI is a UTI a person may acquire after a doctor inserts a urinary catheter. Pathogens can travel along the catheter and enter the urinary tract. The bacterium Escherichia coli is the most common cause of CAUTI.


Symptoms of a UTI include:

Diagnosis and treatment

A doctor will diagnose CAUTI by administering a urine test. To treat it, they will remove or change the catheter and administer antibiotics.

Potential complications

Possible complications of CAUTI include:

An SSI is an infection that occurs in the part of the body where the surgery took place. The infection can be superficial and only affect the skin, or it can be more severe and affect:

  • organs
  • tissues
  • skin
  • surgically implanted material


Symptoms of SSI include:

  • fever
  • drainage of cloudy fluid from the wound
  • pain and redness around the area of surgery

Diagnosis and treatment

A doctor will look for visible signs of infection and perform blood tests to diagnose SSI. To treat it, they will prescribe antibiotics. A person may also require further surgery to treat the infection.

Potential complications

SSIs can lead to life threatening conditions, such as sepsis, as well as:

VAP can occur when a person inhales contaminated material through a ventilator. Pathogens that travel through the ventilator can cause pneumonia after 48 hours of intubation. Of people requiring manual ventilation, 5–15% develop VAP.


Symptoms of VAP include:

Diagnosis and treatment

A doctor may diagnose VAP using:

  • visible signs of infection
  • chest X-rays
  • samples of secretions from the lower respiratory tract
  • blood tests
  • biopsy

Doctors typically treat VAP with antibiotics.

Potential complications

Complications of VAP include:

A person may acquire a bacterial infection during healthcare. These include:

  • Staphylococcus aureus:This bacterium, which people often call staph, is typically present inside the nose and on the skin of about 30% of people. It does not usually cause harm, and infections can appear as skin conditions.
  • Streptococcus species: This bacterium can cause several infections, including:
  • Enterococcus species: This bacterium is the leading cause of nosocomial infections in healthcare settings and is resistant to antibiotics. It is most associated with the following types of infections:
    • UTIs
    • medical device infections
    • soft tissue


Symptoms vary depending on the type of bacteria and infection that affect a patient.

They may include:

  • a rash
  • sore, red throat
  • skin infection
  • symptoms of pneumonia, such as cough, difficulty breathing, and rapid heartbeat
  • symptoms of UTI, such as a burning sensation when urinating or needing to urinate more often
  • symptoms of toxic shock syndrome, such as fever, diarrhea, and dizziness

Diagnosis and treatment

A doctor typically diagnoses bacterial infections by examining a person’s physical symptoms and blood tests.

Antibiotics are generally effective treatments against bacterial infections. A doctor may use different types to treat different infections.

Potential complications

Complications of bacterial infections include:

  • sepsis
  • pneumonia
  • endocarditis, a rare condition that involves inflammation of the heart’s lining, muscles, and valves
  • osteomyelitis, an infection and inflammation of the bone

Nosocomial infections may also be:

  • Fungal: Mold infections and candidiasis are common causes of nosocomial infections. They most often lead to UTIs and bloodstream infections. Experts often associate them with:
    • a contaminated environment
    • immunosuppression
    • unclean catheters
  • Viral: Viruses cause up to 5% of nosocomial infections. A person can acquire them from respiratory, fecal, or hand-mouth routes. Viruses that may transfer through healthcare settings include:
  • Gastrointestinal: Some bacteria can pass through the intestinal walls and cause infection in susceptible people.


Symptoms of other types of infection include:


A doctor will diagnose these infections by examining the physical symptoms and performing laboratory tests, including blood tests, to reveal which pathogens affect the patient.


Treatments vary according to the type of infection.

  • Fungal: A doctor will treat a fungal infection with traditional treatments, such as antibiotics and antifungal medications.
  • Viral: Antibiotics cannot treat viruses. In some cases, doctors can only treat symptoms, and antiviral drugs are available to treat certain kinds of viruses.
  • Gastrointestinal: A doctor may prescribe antibiotics to treat a gastrointestinal infection.

Potential complications

Infection can lead to more severe infections and complications such as sepsis.

Some people are at higher risk than others of nosocomial infection. These risk factors include:

  • prolonged hospital stay
  • being of older age
  • working in a hospital or healthcare facility, although people should follow hygiene best practices to help avoid infections
  • catheter insertion
  • recent or frequent antibiotic use
  • receiving healthcare in a developing country
  • having a compromised immune system
  • having other chronic illnesses
  • malnutrition
  • obesity
  • using tobacco
  • using certain medications, such as gastric acid-suppressing medication

Doctors will inform people of the potential risk of developing infections when receiving care.

Medical professional workers will assess a person’s risk factors for developing specific infections and provide measures to help minimize them.

Healthcare workers and patients can help prevent nosocomial infection. Preventive measures include:

  • healthcare workers practicing good hand hygiene
  • personal protective equipment for healthcare workers, such as gloves and masks
  • proper cleaning of all surfaces and clearing away of hospital waste
  • antibiotic control policies to prevent overusing antibiotics, which can lead to resistance
  • patients cleaning, not shaving, relevant areas before surgery
  • healthcare workers educating patients on proper care of medical devices
  • patients trying to quit smoking, if applicable
  • patients practicing good hygiene during the healing process

The outlook for a nosocomial infection varies by its type and severity.

Researchers have not fully documented the mortality rates of these infections, which vary between sources of information.

Some studies show a 10% mortality rate, while others argue there is a 12–80% mortality rate for these infections, depending on the definitions researchers include in studies. Therefore, more research needs to determine more conclusive figures.

An international study from the above research found that people in the ICU with nosocomial infections had a 25% mortality rate. The study also found that while there was a 15% mortality rate for hospital patients overall, there was a 30% mortality rate for those with nosocomial infection.

Nosocomial infections are infections that a person may acquire while receiving healthcare. The infection is not usually present before their admittance, and the individual acquires it in a setting such as a hospital or long-term care facility.

These infections often occur with catheters, surgery, or medical device implantation. Different types of nosocomial infections can lead to different symptoms and complications. Doctors can provide a prompt diagnosis and treatment depending on the type of infection.