Pseudomonas bacteria were first described in the late 19th and early 20th centuries, the genus was formally named in 1894 by the German botanist Walter Migula. Since then, numerous species within the genus have been identified and characterised, with P. aeruginosa emerging as one of the most extensively studied and clinically relevant species due to its pathogenicity and widespread presence in Healthcare Associated Infections (HAIs).


  • This is the most clinically significant species within the genus Pseudomonas as it is often antibiotic-resistant and is a major cause of morbidity and mortality among hospitalised patients. P. aeruginosa is an opportunistic pathogen associated with a wide range of infections, including respiratory tract infections, urinary tract infections, wound infections, and bloodstream infections.
  • Pseudomonas bacteria can colonise and proliferate in water systems such as sinks, outlets, showers, and medical devices. Exposure to contaminated water droplets or direct contact with contaminated surfaces can lead to infection.

Infection Statistics

Globally, the rates of P. aeruginosa infections have been on a general upward trend. This may be partially attributed to the increasing prevalence of risk factors for P. aeruginosa infections, such as an aging population, an increase in chronic disease burden, increased use of medical devices, and an increase in the number of immunocompromised individuals.

In 2018, Public Health England reported 4,745 cases of Pseudomonas spp. bacteremia across England, Wales, and Northern Ireland.

The rate of reported cases increased by 10.7% between 2009 and 2018, from 7.0 to 7.8 reports per 100,000 population.

While a total of 4,409 cases of P. aeruginosa bacteremia were reported in England alone between 1 April 2022 and 31 March 2023.

Hospital Acquired Infections

Pseudomonas infections are a significant concern in healthcare facilities, where the bacteria can spread via contaminated medical equipment, devices, surfaces, and water sources. Patients in augmented care and those undergoing invasive medical procedures are at heightened risk.

Neonatal intensive care units (NICUs), Haemato-Oncology, Bone Marrow Transplant Units, and burn units are examples of augmented care settings where patients are vulnerable to Pseudomonas infections.

Neonates, particularly premature infants, or those with low birth weight, have underdeveloped immune systems and fragile skin barriers, making them susceptible to infection. Burn patients are at increased risk of Pseudomonas wound infections due to compromised skin barriers and the conducive environment provided by burn wounds for bacterial colonisation.

Individuals with cystic fibrosis (CF) are also particularly susceptible to Pseudomonas infections, especially in the respiratory tract. CF patients have thick, sticky mucus in their airways, which provides an ideal environment for bacterial colonisation and persistence.

Treatment of Pseudomonas infections typically involves antimicrobial therapy, although the choice of antibiotics may be limited due to the bacteria’s inherent resistance to many antibiotics. In severe cases, supportive care and targeted therapies may be necessary to manage complications and prevent further spread of the infection. Early diagnosis and appropriate management are crucial for improving outcomes in individuals with Pseudomonas infections.

Infection Transmission Routes

Pseudomonas bacteria, particularly P. aeruginosa, can be transmitted through various routes that affect certain groups of individuals who may be at higher risk of infection.


Ingestion of Pseudomonas contaminated water or food can lead to gastrointestinal infections, though this route is less common than respiratory or contact transmission.

Transfer by Touch/Splashing

Direct contact with contaminated surfaces or objects, as well as exposure to splashes from contaminated water sources, can lead to transmission. This route of transmission is particularly relevant in healthcare settings where Pseudomonas-contaminated medical equipment, surfaces, or water sources can pose a risk to patients, visitors, and healthcare workers.

Contaminated Medical Devices

Pseudomonas bacteria can colonise and proliferate on medical devices such as urinary catheters, ventilators, respiratory therapy equipment, humidified incubators, intravenous catheters, and cleaning equipment. Patients who require invasive procedures, prolonged hospital stays, or frequent use of medical devices are at increased risk of device-associated Pseudomonas infections.

Control of Pseudomonas

Whilst Legionella control is often characterised as an ‘estates and maintenance’ issue, Pseudomonas is regarded as an ‘everyone’ problem. This is due to the environmental prevalence of Pseudomonas and the wide range of transmission routes that can impact patients.

Preventive measures such as proper hand hygiene, infection control practices, maintenance of water systems, and antimicrobial stewardship are essential for reducing the risk of Pseudomonas infections, particularly in healthcare settings.

Timely identification, treatment, and management of infections are crucial for improving outcomes, especially in vulnerable populations. The impact on human health can vary depending on the site of infection and the overall health status of the affected individual.

Related insights

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