Pseudomonas Infections | Definition and Patient Education

Pseudomonas Infections

What Are Pseudomonas Infections?

Pseudomonas infections are diseases caused by a bacterium from the genus Pseudomonas. The bacteria are found widely in the environment, such as in soil, water, and plants. They usually do not cause infection in healthy people. If an infection does occur in a healthy person, it is generally mild.

More severe infections occur in people who are already hospitalized with another illness or condition. Pseudomonades are one of the most common pathogens involved in hospital infections.  A pathogen is a microorganism that causes disease. Infections acquired in a hospital are called nosocomial infections. 

Infections can occur in any part of the body. Symptoms depend on which part of the body is infected. Antibiotics are used to treat the infections. Patients who are already very ill can die from a Pseudomonas infection.

What Causes Pseudomonas Infections?

Pseudomonas infections are caused by a free-living bacterium from the genus Pseudomonas. Pseudomonas are gram-negative bacteria. They are found widely in soil and water. They favor moist areas. Only a few of the many species cause disease. The most common species that causes infection is called Pseudomonas aeruginosa. (CDC)

Who Is at Risk for Pseudomonas Infections?

Healthy people are usually not at risk of infection. People who already have a weakened immune system because of another illness or condition are at a higher risk of infection. This is especially true for patients who are hospitalized for an extended period of time. The bacteria can be spread in hospitals via the hands of healthcare workers or by hospital equipment that is not properly cleaned.

Pseudomonas infections are considered opportunistic infections. This means that the organism only causes disease when a person’s immune system is already impaired.

Conditions that may increase the risk of infection include:

  • burn wounds
  • cancer patients receiving chemotherapy
  • cystic fibrosis
  • HIV or AIDS
  • presence of a foreign body, like a mechanical ventilator or catheter
  • patients undergoing an invasive procedure, like a surgery

Infections can be severe in patients whose immune systems are already compromised.

Very mild illnesses like skin rashes and ear infections have been reported in healthy individuals. The infection might occur after exposure to hot tubs and swimming pools that are inadequately chlorinated. (CDC) This is sometimes called “hot-tub rash.” Eye infections can occur due to infected contact lens solution in people who wear contacts.

What Are the Symptoms of Pseudomonas Infections?

Infections in the skin tend to be less severe than infections that occur in the blood or lungs. Specific symptoms depend on where the infection occurs:


A bacterial infection of the blood is called bacteremia. A blood infection is one of the most severe infections caused by this organism (Lin & Chen, 2006). Symptoms may include:

  • fever
  • chills
  • fatigue
  • muscle and joint pains


Infection of the lungs is called pneumonia. Symptoms include:

  • chills
  • fever
  • cough that is productive
  • difficulty breathing


A skin infection caused by this bacteria is often a folliculitis. Symptoms may include:

  • itchy rash
  • bleeding ulcers
  • headache


An external ear canal infection may sometimes be caused by Pseudomonas and result in “swimmer’s ear.” Symptoms may include:

  • swelling
  • ear pain
  • itching inside the ear
  • discharge from the ear
  • difficulty hearing


Symptoms of an eye infection may include:

  • inflammation
  • pus
  • pain
  • swelling
  • redness
  • impaired vision

How Are Pseudomonas Infections Diagnosed?

A diagnosis is made by sending a sample of pus, blood, or tissue to a laboratory. The laboratory will then test for the presence of Pseudomonas.

How Are Pseudomonas Infections Treated?

Pseudomonas infections are treated with antibiotics. Unfortunately, many hospital infections are becoming more difficult to treat. These bacteria have developed the ability to adapt and overcome antibiotics in their environment. This is called antibiotic resistance.

The increase in antibiotic resistance has made treating infections much more challenging. Pseudomonas can often develop resistance to multiple types of antibiotics. It can even sometimes develop resistance during the course of treatment (Lister et al, 2002).

It is important that a doctor select an effective antibiotic. A doctor may send a specimen from the patient to a laboratory first for testing in order to be more certain. The laboratory will then test the specimen to find out which antibiotic will work the best.

Treatment may involve one or more of the following types of antibiotics:

  • ceftazidime
  • ciprofloxacin
  • aminoglycosides
  • cefepime
  • aztreonam
  • carbapenems
  • ticarcillin
  • ureidopenicillins

Mild skin infections may resolve on their own without treatment.

How Can Pseudomonas Infections be Prevented?

Thoroughly washing hands and cleaning equipment in hospitals can help prevent infection. Outside a hospital, avoiding hot tubs and pools that are poorly cared for can help prevent infections. You should remove swimming garments and shower with soap after getting out of the water. Drying your ears after swimming can also help prevent swimmer’s ear.

What Can be Expected Long-Term?

Ear infections and skin infections from swimming pools and hot tubs are typically mild.

Severe infections can be deadly if not treated right away. Death rates are much higher in patients infected with a type of Pseudomonas that is resistant to multiple types of antibiotics (Giamarellou, 2002). Hospital mortality from bloodstream infections may be greater than 20 percent. It is highest in patients who receive the wrong initial antibiotic treatment (Micek et al, 2005).

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