Microbial Top Facts: Pseudomonas aeruginosa

Continuing our blog series of microbial top facts, today we feature Pseudomonas aeruginosa (P. aeruginosa), a bacterium cultured frequently at our laboratory. It was discovered in 1882 by Carle Gessard through an experiment that identified this microbe by its water-soluble pigments that turned a blue-green when exposed to ultra-violet light. Here are some facts about P. aeruginosa you may not know.

Where can we find Pseudomonas aeruginosa

Pseudomonas can be found in the outdoors, particularly in soil, coastal areas, plant/animal tissues but can easily withstand a variety of different environmental stresses. Like many environmental bacteria, P. aeruginosa live in ‘slime-enclosed’ biofilms which allow for survival and replication within human tissues and medical devices.

What makes it thrive

P. aeruginosa thrives in moist environments such as soil and water. It can be found in large numbers on fresh fruits and vegetables. Known as an opportunistic pathogen, human colonisation begins within the gastrointestinal tract, with subsequent spread to moist cutaneous sites such as the perineum and axilla.

What can it cause

To initiate an infection, there must be a break in the first-line defences of the body. For example, this could be due to trauma, surgery, cancer, serious burns, or other immunocompromising states. The bacteria communicate with each other via chemical signals, known as quorum sensing. This can trigger biofilm formation and other factors which can cause disease. The production of a biofilm protects P. aeruginosa from host-produced antibodies and phagocytes contributing to antibiotic resistance of this organism. Pseudomonas aeruginosa is a nosocomial pathogen which can present severe complications in patients with existing health conditions, such as pneumonia.

Why test for it

Currently, it is one of the most troublesome multidrug-resistant bacterial causes of nosocomial infections. Infection with Pseudomonas aeruginosa can cause long-term chronic diseases, particularly affecting immunocompromised patients. Therefore, early detection is critical for treating a Pseudomonas aeruginosa infection, as they are also difficult organisms to eradicate from areas that become contaminated, such as operating rooms, hospital rooms, clinics, and medical equipment.