Occurrence Of Legionella Spp. In Water-Main Biofilms

Q: Can Legionella bacteria be found in municipal drinking water pipelines?

Yes, studies confirm Legionella spp. are detected in water-main biofilms within municipal drinking water distribution systems. These biofilms serve as a significant reservoir for this potentially lethal pathogen, as demonstrated by findings in a no-residual system where Legionella was frequently detected in 10 of 23 samples.

Q: How do water-main biofilms contribute to Legionella risk?

Water-main biofilms provide an ideal environment for Legionella spp. to colonize and thrive, acting as a persistent source for tap water and premise plumbing systems. The bacteria are particularly well-adapted to these complex microbial communities, which can protect them from disinfectants.

Q: What role do disinfectant residuals play in controlling Legionella in water distribution?

Maintaining a disinfectant residual, such as chloramine, is crucial for suppressing Legionella spp. in drinking water distribution systems. A study comparing a chloraminated system to one with no residual found significantly lower Legionella in the chloraminated system, with no detection in 35 samples compared to frequent detection in the no-residual system.

Q: What are the essential strategies to minimize Legionella risk in piped water systems?

To minimize Legionella risk, it is essential to maintain adequate disinfectant residuals, control water temperature in distribution lines, and implement regular flushing and monitoring programs. These proactive measures help prevent the colonization and proliferation of Legionella spp. in biofilms.

Q: What health issues are caused by Legionella species found in water?

Legionella pneumophila and related species are responsible for Legionnaires' disease, a severe form of pneumonia, and Pontiac fever, a milder flu-like illness. These gram-negative bacteria pose a serious public health risk when they colonize water systems and become aerosolized.

Key Finding: We found Legionella in water-main biofilms in two city drinking water systems. This proves that these biofilms, the slimy stuff that builds up inside pipes, can hide this dangerous pathogen. So, what do we do? Keeping enough disinfectant in the water, controlling the temperature in those pipes, and regularly flushing and checking the system are all crucial steps to cut down on Legionella risk.

Waak, Michael B.; LaPara, Timothy M.; Halle, Cynthia; Hozalski, Raymond M.

ENVIRONMENTAL SCIENCE & TECHNOLOGY, 52 (14):7630-7639; 10.1021/acs.est.8b01170 JUL 17 2018

Abstract: Many places in the US add chlorine or chloramine to drinking water to kill bad germs. In Europe, that’s less common. We wanted to see how this difference played out. We looked for Bacteria and Legionella in water-main biofilms and tap water. We compared a US system that uses chloramine to a Norwegian system that doesn’t use any disinfectant. We used a test called real-time quantitative polymerase chain reaction (qPCR). Even though the chloraminated system generally had warmer water and more food for bacteria, it had way fewer total Bacteria and Legionella in its biofilms and tap water (p < 0.05). In fact, we didn’t find any Legionella in the chloraminated system’s biofilms (0 out of 35 samples). But in the system with no disinfectant? We found Legionella often, in 10 out of 23 samples, with one sample having as many as 7.8 x 10(4) gene copies per square centimeter. Our study suggests that water-main biofilms can be a source of Legionella that gets into your tap water and home plumbing. Using chloramine seems to help keep those numbers down.

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Source: Water Feed

Frequently Asked Questions

Can Legionella bacteria be found in municipal drinking water pipelines?
Yes, studies confirm Legionella spp. are detected in water-main biofilms within municipal drinking water distribution systems. These biofilms serve as a significant reservoir for this potentially lethal pathogen, as demonstrated by findings in a no-residual system where Legionella was frequently detected in 10 of 23 samples.

How do water-main biofilms contribute to Legionella risk?
Water-main biofilms provide an ideal environment for Legionella spp. to colonize and thrive, acting as a persistent source for tap water and premise plumbing systems. The bacteria are particularly well-adapted to these complex microbial communities, which can protect them from disinfectants.

What role do disinfectant residuals play in controlling Legionella in water distribution?
Maintaining a disinfectant residual, such as chloramine, is crucial for suppressing Legionella spp. in drinking water distribution systems. A study comparing a chloraminated system to one with no residual found significantly lower Legionella in the chloraminated system, with no detection in 35 samples compared to frequent detection in the no-residual system.

What are the essential strategies to minimize Legionella risk in piped water systems?
To minimize Legionella risk, it is essential to maintain adequate disinfectant residuals, control water temperature in distribution lines, and implement regular flushing and monitoring programs. These proactive measures help prevent the colonization and proliferation of Legionella spp. in biofilms.

What health issues are caused by Legionella species found in water?
Legionella pneumophila and related species are responsible for Legionnaires’ disease, a severe form of pneumonia, and Pontiac fever, a milder flu-like illness. These gram-negative bacteria pose a serious public health risk when they colonize water systems and become aerosolized.