Spartan Bioscience announced scientific results from a Legionella testing study of Canadian federal government buildings. The 12-week study tested 51 cooling towers in Ottawa, Toronto, and Montreal and compared weekly on-site Legionella DNA testing vs. monthly Legionella culture testing. Legionella DNA testing was performed with the Spartan Legionella Detection System.
The study was designed and performed in collaboration with Public Services and Procurement Canada (PSPC). PSPC was one of the world’s first organizations to adopt rigorous Legionella testing standards and has been at the forefront of proactively protecting public health by incorporating new technologies and standards. Funding for the study was provided by the Build in Canada Innovation Program (BCIP).
“PSPC is a leader in Legionella testing and management,” said Paul Lem, M.D., CEO of Spartan Bioscience. “This is the first scientific study of weekly Legionella DNA testing and we are grateful for PSPC’s support. It is an excellent example of how the Canadian government supports innovation.”
The study’s main finding was that 39 percent of cooling towers tested positive for Legionella DNA levels greater than 10 bacteria per milliliter and 8 percent of cooling towers tested positive for Legionella DNA levels greater than 100 bacteria per milliliter during the study period. To put this in perspective, Quebec regulations call for cooling towers to be disinfected when the Legionella level is greater than 10 bacteria per milliliter. Similarly, the action level is 20 bacteria per milliliter in New York State.
There were two other key findings. First, on-site Legionella DNA testing was significantly more accurate than shipping water samples to a laboratory for Legionella culture testing. This finding was consistent with previous research. For example, the Centers for Disease Control and Prevention (CDC) found that Legionella culture underestimated actual levels by a factor of 10 or more. The CDC also found culture incorrectly reported that water samples were negative for Legionella when in fact they were positive an average of 11.5 percent of the time.
Second, weekly on-site Legionella DNA testing was able to rapidly detect when Legionella bacteria grew to a higher action level. The doubling time of Legionella bacteria is typically between 22–72 hours in water systems and the natural environment. However, the doubling time at an “amplifier site” (such as a cooling tower) can be as few as 2.5 hours. Overall, weekly testing is important because Legionella can reach high levels within days. Spartan plans to publish more detailed findings from the study in upcoming peer-reviewed scientific publications.
Publication date: 3/22/2018