Pseudomonas aeruginosa

Discovery

In 1882 Carle Gessard, a chemist and bacteriologist from France, discovered Pseudomonas aeruginosa via an experiment that identified this microbe by its water soluble pigments that turned a blue-green when exposed to ultra-violet light.

What is Pseudomonas aeruginosa?

Pseudomonas aeruginosa is a common bacterium that can cause disease in animals, including humans, and can survive in both aerobic and anaerobic conditions. It is often found in moist areas such as water and soil.

Pseudomonas aeruginosa is reported to have colonized in more than fifty percent of humans, where they reside as opportunistic pathogens. The mortality rate of those infected is over 50% and it kills about 1000 people per year.

The most vulnerable are those with severe burns or suppressed immune systems such as premature babies, AIDS patients, and cancer patients (intensive care patients).

How is Pseudomonas aeruginosa spread?

Pseudomonas is spread by direct contact with the organism on a contaminated surface or instrument, including medical equipment such as catheters which aren’t properly sterilised after use with a patient. It can also spread via contaminated food and water, and contaminated hands which have not been washed.

What kind of illness does it cause?

If it enters lung tissue, for example in a cystic fibrosispatient, it can cause pneumonia.

Infection of a skin wound or burn can lead to extensivetissue damage and even septicemia which could lead to a septic shock.

If the bacterium infects the gastro-intestinal system, for example Via a catheter, then necrotising enterocolitis can follow, which is the second most common cause of morbidity in premature Infants.

Treatments

Pseudomonas infections are treated with antibiotics. However, about 13% of severe healthcare-associated infections caused by Pseudomonas aeruginosa are multidrug resistant, meaning several classes of antibiotics can no longer cure these infections.

Their resistance to most antibiotics is attributed to efflux pumps, which pump out some antibiotics before the antibiotics are able to act. Usually, a combination of antibiotics prescribed and most must be injected.

Another method of treatment in ‘phage therapy’ in which viruses invade bacterial cells and disrupt bacterial metabolism, causing the bacterium to lyse. It is said to have fewer side effects in comparison to antibiotics. However, phage therapy is only approved in Russia and Georgia.