Legionella has an old-fashioned ring to it, but this bacterium is causing pneumonia outbreaks (Legionnaires’ Disease and Pontiac Fever) in modern, urban areas like Brooklyn and Chicago. Spread by infected water vapor carried by cooling towers and HVAC systems, these Legionella outbreaks hit vulnerable populations — largely children and senior citizens — the hardest, sometimes leading to death.
Blame is being lobbed around, but the reason for recent outbreaks is still uncertain. Cooling towers and HVAC systems can be disinfected, and operating procedures altered to discourage Legionella, but it doesn’t answer the question of how the bacteria got there in the first place.
Dealing with Legionella could mean disaster in your lab if you have a poorly designed autoclave. Bernie Youngblood, president of Priorclave North America, has long been concerned about some autoclave designs that are becoming popular in North America. “The problem is that many research labs are beginning to use sterilizers that rely on ‘warm bath’ drain cooling. With a ‘warm bath’ configuration, it’s entirely possible that you can end up with a reservoir of static water held at a steady 80 – 140°F — ideal for breeding Legionella. Combine this with the fact that much of an autoclave’s exhaust, before the sterilization period is completed, can be biohazardous, and you have an ideal breeding ground for any number of pathogens.”
This is why Priorclave North America does not recommend the use of warm bath drain cooling (it is actually illegal in the EU), and advises research labs to always work closely with their autoclave supplier to develop a solution that minimizes the use of water for the purposes of drain cooling, while eliminating the risks associated with cross-contamination.