Legionella is common in many environments.It has a minimum of 34 species identified. Legionella is the motile aerobic rod-shaped Gram-negative bacterium that thrives in heating and air conditioning systems and even in appliances(i.e. ice machines) that are equipped with water reservoirs and can cause Legionnaires’ disease. L. pneumophila serogroup 1 is the most frequently identified form of the bacterium isolated from patients with Legionnaires’ disease, although other serogroups and subtypes of the bacterium are frequently isolated from water sources.
The diseases produced by Legionella are called legionellosis. More than 34 species of Legionella have been identified, and more than 20 linked with human diseases. L. pneumophila causes the pneumonia known as Legionnaires’ disease and the flu-like Pontiac fever.
Legionella has certain growth requirements that need to be met in order for it to continue to survive and grow. Some of these growth requirements include temperatures above 8 degrees, mass amounts of iron and L Cysteine and biofilm.
According to OSHA, water sources that frequently provide optimal conditions for growth of the organisms include:
- cooling towers, evaporative condensers, and fluid coolers that use evaporation to reject heat. These include many industrial processes that use water to remove excess heat;
- domestic hot-water systems with water heaters that operate below 60°C (140°F) and deliver water to taps below 50°C (122°F);
- humidifiers and decorative fountains that create a water spray and use water at temperatures favorable to growth;
- spas and whirlpools;
- dental water lines, which are frequently maintained at temperature above 20°C (68°F) and sometimes as warm as 37°C (98.6°F) for patient comfort; and
- other sources including stagnant water in fire sprinkler systems and warm water for eye washes and safety showers.
Water stored below 20°C (68°F) is generally not a source for amplified L. pneumophila levels. However, high levels of bacteria have been measured in the water supplying ice machines. The source of amplification in this case was thought to be heat from the condenser coil of the ice maker to the cold water supply. However, no cases of Legionnaires’ disease have been linked to consumption of ice made from contaminated water.
Services offered include:
Obtain an overview of all water systems at the building following the OSHA Technical Manual protocols.
- Conduct a walk-through investigation of the building.
- Assess the results of the walkthrough investigation to evaluate the next action plan.
- Recommend control action plans include proper system temperatures, eliminating dead legs.
- Collect water samples to identify Legionella levels after correction actions are successfully completed.