Pseudomonas aeruginosa
Pseudomonas aeruginosa is very common in the environment, particularly in fresh water and soil. It is an opportunistic pathogen in humans: it rarely affects otherwise healthy individuals, but can cause disease in those with a weakened immune system or pre-existing infection or medical condition. Infections are most often hospital- or healthcare-associated.
Mechanism of transmission: Pseudomonas aeruginosa can be transmitted in many ways: contaminated food (such as fruits and vegetables) or drink, through water sources such as swimming pools, through contaminated medical equipment, or through direct contact from contaminated hands.
Number of cases: In 2017, P. aeruginosa caused over 32,000 hospital-associated infections and almost 3,000 deaths in the US1.
Pseudomonas aeruginosa infections
Pseudomonas aeruginosa can infect many different areas of the body, causing a wide range of diseases. These include infections of the skin, digestive system and urinary tract, respiratory system (lungs), and bloodstream. Estimates of mortality rates for P. aeruginosa infections range from 18% to 61%1.
Individuals that are otherwise healthy are rarely infected by Pseudomonas aeruginosa, and when infections do occur they are mild (for example, skin rash or mild eye infection). However, P. aeruginosa can cause severe infections in those with a weakened immune system or pre-existing medical condition (such as cystic fibrosis, diabetes, or cancer), patients with open wounds or burns, and those using a medical device inserted into the body such as a catheter or ventilator. It is a major cause of nosocomial (hospital-acquired) infections.
P. aeruginosa infections are particularly associated with cystic fibrosis: over 60% of adults with this condition also suffer from chronic lung infections which are life-threatening in many cases2.
Antibiotic resistance in Pseudomonas aeruginosa
Antimicrobial resistance (AMR) occurs when a bacteria is able to survive treatment with antibiotics, and means such treatment fails to cure the infection. Pseudomonas aeruginosa strains (subtypes) can be resistant to many commonly-used antibiotics, through a wide range of mechanisms. For example, these mechanisms include making proteins that destroy or inactivate the antibiotic before it can damage the bacteria, or producing proteins known as efflux pumps that pump the antibiotics back out of the bacterial cell. P. aeruginosa can also form biofilms, an aggregate of bacterial cells stuck to each other, which can increase their collective AMR and also help protect them against the human immune system.
Some Pseudomonas aeruginosa strains are resistant to many different antibiotics at the same time, and so are referred to as multi-drug resistant. Multi-drug resistance particularly occurs in hospital-associated strains, which means it can be very difficult to effectively treat severe nosocomial P. aeruginosa infections. Because of this, the World Health Organisation lists Pseudomonas aeruginosa as a critical priority for research into AMR and development of new antibiotics3.
Genomics and Pseudomonas aeruginosa
Genomic data can be used to study antimicrobial resistance in P. aeruginosa including how different mechanisms of resistance occur, and their evolution and spread. This information can inform research into new treatments. Genome data is also used in the study of other factors of P. aeruginosa infections, such as how the bacteria invade the body and evade the immune system, or how different characteristics of the bacteria can influence the severity of the resulting disease. Continued research into Pseudomonas aeruginosa is crucial to increase our understanding of related infections and so improve our ability to tackle the diseases it causes.
If you are keen to find out more about Pseudomonas aeruginosa, these websites are good places to go for more information:
