Pseudomonas aeruginosa

Pseudomonas aeruginosa is an aquatic bacterium, present everywhere in the environment, in freshwater, the soil and plants.

It is a constant and plentiful presence in waste water and as a result in surface water that receives polluted effluents, but nevertheless it can develop in the purest water such as natural mineral water.

The ecological niche for Pseudomonas aeruginosa is characterised by a weak ion concentration (fresh water), a low organic material content (sugars and proteins) and a brad temperature range, between 4°C and 43°C (optimum temperature for growth being 42°C).

In the event of a water supply being colonised, thermal treatment by circulating water at 70°C for 30 minutes is often the only way of reducing contamination, provided no scaling, corrosion products or dead legs are present.

In man, an opportunistic pathogen, responsible in healthcare institutions for serious and often fatal nosocomial infections (30% fatality rate in receptive populations), is the source of 10 to 20% of nosocomial infections.

Pathogenicity is basically of concern to patients with weakened local and/or systemic defence mechanisms:

1. Burns patients, cancer sufferers or patients with leukaemia, patients hospitalised in intensive care units undergoing multiple invasive procedures (endotracheal intubation, venous catheterisation, urinary catheters, etc.),
2. Patients suffering from cystic fibrosis, patients with wounds, bedsores, or injuries prone to infection.

When favourable conditions combine, it is capable of penetrating transcutaneously, colonising cutaneous surfaces and mucous membranes, then invading and destroying underlying tissues.

Pseudomonas aeruginosa is both an opportunistic pathogenic bacteria and an indicator of environmental contamination for water intended for human consumption in healthcare establishments and for water in medical swimming pools (used by patients with weakened immune systems).