Pseudomonas infections
Pseudomonas infections are caused by the gram-negative bacterium Pseudomonas, primarily P. aeruginosa, and can affect various body parts, including the skin, lungs, and bloodstream. While these infections can range from mild to severe, they predominantly occur in individuals with weakened immune systems, such as hospitalized patients or those with chronic illnesses like diabetes or cystic fibrosis. The bacterium is commonly found in soil and water and can enter the body through breaks in the skin or via medical devices like catheters. Symptoms vary based on the infection site and can include fever, pain, and respiratory difficulties. Diagnosis typically involves culturing samples from the infected site, while treatment often requires a combination of specialized antibiotics and supportive care. Preventive measures focus on maintaining good hygiene practices, especially in hospital environments, to minimize the risk of infection. Understanding these aspects is crucial for those at higher risk or caring for vulnerable populations.
Pseudomonas infections
ANATOMY OR SYSTEM AFFECTED: All
ALSO KNOWN AS: Pseudomonal bacteremia
Definition
Infections of skin, blood, bones, eyes, ears, the central nervous system, the heart, the lungs, the gastrointestinal system, wounds, and the urinary tract may all be traced to an infection with the bacterium Pseudomonas. Ranging from mild to life-threatening, Pseudomonas infection rarely affects healthy persons and is often the cause of hospital-acquired, or nosocomial, infections. All infections are potentially curable, but infection with Pseudomonas is one of the most difficult types to treat. Pseudomonas is present in soil and water and also can be found on plants, animals, and healthy persons.
Causes
Pseudomonas infections are caused by the gram-negative Pseudomonas bacterium. The most prevalent is P. aeruginosa. Any bodily organ or part may be infected with Pseudomonas.
Risk Factors
Considered an opportunistic bacterium, Pseudomonas attacks debilitated persons, often those who are hospitalized or who have a disorder that weakens the immune system. Any break in the skin or the use of any medical device, such as a urine catheter, may provide an opportunity for the bacterium to enter the body and cause infection. Persons with diabetes or cystic fibrosis are at greater risk. Persons with human immunodeficiency virus (HIV) infection or cancer, and transplant recipients, are at increased risk because of their weakened immune systems, usually caused by the drugs they take to treat their diseases.
Symptoms
P. aeruginosa may infect a variety of sites in the body, and symptoms depend on the site involved. External otitis, or swimmer’s ear, causes pain and a discharge from the ear canal, whereas malignant external otitis seen in persons with diabetes has symptoms of fever, loss of hearing, and severe pain. Drainage is often seen in eye infections with Pseudomonas. Skin infections cause lesions or develop in open sores and may have a green-blue drainage with a fruity odor. Infection of the heart, or endocarditis, comes with a fever, a heart murmur, lesions, and an enlarged spleen.
Diarrhea and dehydration are the most common symptoms of gastrointestinal infections. Pneumonia with fever, difficulty breathing with a rattling sound, and lack of oxygen are symptoms of respiratory system infections. Fever, headache, and confusion are seen in persons with meningitis caused by Pseudomonas infection. Bacterial blood infection, or bacteremia, comes with jaundice, fever, rapid breathing, and a rapid heart rate. Lesions may occur with any Pseudomonas infection.
Screening and Diagnosis
The clinical site of the infection is cultured to determine the causative organism for the person’s symptoms. Blood, wound drainage, body fluids, and tissue are sent to a laboratory for culture to determine the presence of Pseudomonas bacteria. Radiology or X-ray studies may show lesions within the body, but cultures are the only way to determine the actual organism causing problems. Doctors may also use ultrasounds, stethoscopes, and physical examinations to diagnose Pseudomonas infections.
Treatment and Therapy
Antipseudomonal antibiotics in combination are used to treat the infection. Supportive therapy, depending on the clinical condition of the infected person, is used. Hospitalization may be needed if symptoms are severe. Respiratory support, including the use of mechanical ventilation, may be indicated. Finally, the revision of wounds and the surgical removal of abscesses are options.
A small percentage of Pseudomonas aeruginosa is now resistant to carbapenem antibiotics. For this reason, most available antibiotics do not function against this variety of Pseudomonas.
Prevention and Outcomes
Good hygiene is the best prevention against Pseudomonas infection. Washing food carefully, drinking safe water, not tracking dirt from shoes into living spaces, and handwashing are helpful. In hospital settings, one should avoid the use of catheters, should change bandages often, and should clean equipment (such as ventilators, restrooms, and mops and other cleaning supplies) where moist conditions are commonly found.
Bibliography
Blaser, Martin J. “Introduction to Bacteria and Bacterial Diseases.” In Mandell, Douglas, and Bennett’s Principles and Practice of Infectious Diseases, edited by Gerald L. Mandell, John F. Bennett, and Raphael Dolin. 7th ed. New York: Churchill Livingstone/Elsevier, 2010.
"Pseudomonas Aeruginosa Infection." Cleveland Clinic, 21 July 2023, my.clevelandclinic.org/health/diseases/25164-pseudomonas-infection. Accessed 4 Feb. 2025.
Salyers, Abigail A., and Dixie D. Whitt. Bacterial Pathogenesis: A Molecular Approach. 2d ed. Washington, D.C.: ASM Press, 2002.
St. Georgiev, Vassil. Opportunistic Infections: Treatment and Prophylaxis. Totowa, N.J.: Humana Press, 2003.