Legionella Bacteria Water Sampling Methodology
This blog delves into systematic approaches for Legionella water testing, offering valuable insights into best practices and recommendations to ensure the safety of your water. Importance of quarterly Legionella sampling Building water systems are dynamic and influenced by various factors such as usage patterns, maintenance schedules, and seasonal changes in municipal water quality. These complex interactions can significantly impact water chemistry and microbiology, creating an environment where Legionella bacteria can thrive. To effectively manage and mitigate the risk of Legionella growth, it is crucial to implement regular testing protocols. Conducting quarterly Legionella testing is strongly recommended. This comprehensive approach not only captures potential seasonal fluctuations but also serves as a robust strategy to ensure the ongoing safety and maintenance of water systems. By prioritizing regular testing, building owners and operators can proactively address any emerging issues and safeguard the well-being of occupants. Sampling methodology Routine sampling for Legionella should be performed to be representative of the building’s water systems. This may be based on size, number of water systems, high-risk locations, and water usage. There are a few strategies in the industry for sampling for Legionella. One method involves taking at least ten samples. Another would be to sample 10% of outlets in the building. These rules may vary depending on the system’s size, but at minimum, it should include near, mid, and far samples, as well as other representative locations. For larger structures, collecting additional samples to account for variations across different floors, water risers, and loops is advisable. This ensures a comprehensive understanding of the system’s water quality. Following this rule strikes a balance between representative sampling and obtaining sufficient data to make informed water management and maintenance decisions. Distal site positivity rule in healthcare The risk of healthcare-associated Legionnaires’ disease significantly increases when 30% or more of distal hot water outlets, such as faucets and showers, test positive for Legionella bacteria. Conversely, the risk decreases if the percentage of positive outlets falls below 30%. This approach, establishing a distal site positivity rule of 30%, offers an effective and practical indicator of Legionella risk in healthcare facilities. By implementing this rule, facilities can proactively implement appropriate corrective actions based on the positivity level and utilize their water management program to enhance maintenance, monitoring, and diagnostic procedures to ensure the safety and well-being of their patients and staff. These measures will help mitigate the potential spread of Legionnaires’ disease and foster a healthier environment for all. Water sampling services LiquiTech provides water quality testing and diagnostics services on an ad-hoc basis or as an ongoing service when you partner with us. We will help you to proactively identify harmful contaminants in your building’s water system, provide easy-to-understand test results with interpretation and recommendations by certified water safety specialists, and help you navigate the Department of Health and other regulatory agencies with expert guidance.
Keeping Hospitals Safe: A Success Story with Lucile Packard Children’s Hospital
When Lucile Packard Children’s Hospital Stanford opened its doors in 1991, it was met with an unexpected challenge: Legionella bacteria in the building’s water system. Despite the hospital’s best efforts, traditional disinfection methods failed to control the problem, which led to two tragic patient deaths. The hospital turned to LiquiTech and the LiquiTech™ Copper-Silver Ionization System, an environmentally friendly and safe method to control Legionella, was quickly installed. Following the installation, several days of rigorous system flushing, monitoring, and water testing took place until Legionella was no longer detected. For over 30 years, the hospital’s water supply has been completely free of Legionella due to continuous monitoring, predictive services, and collaboration on interventions by LiquiTech. As Michael Zader, the hospital’s Administration Director, points out, “We’ve been waterborne pathogen-free since partnering with LiquiTech in 1991”. This success story emphasizes the importance of embracing innovative solutions when traditional methods fall short and Lucile Packard Children’s Hospital’s mission to keep their hospital environment safe. Read the full case study here.
An Examination of Dead Legs, Water Flow, and Legionella Growth
The relationship between stagnant sections in building water systems, known as dead legs, water flow conditions, and the risk of Legionella, a bacterium that causes Legionnaires’ disease, is more complex and multifaceted than commonly perceived. In this article, we explore these topics in-depth, using insights from scientific studies and valuable industry observations. Understanding dead legs Dead legs refer to the segments within pipes in a plumbing system where water flow is either significantly reduced or non-existent. These stagnant areas of plumbing can become a breeding ground for bacteria and other contaminants that can compromise water quality. The lack of flow hinders proper disinfection, provides favorable growth conditions, and accumulation of contaminants which can lead to health concerns. Water flow and Legionella growth Water flow plays a crucial role in the growth of Legionella bacteria. Liu’s 2006 study examined the impact of different flow conditions, such as turbulent, laminar, and stagnant, on Legionella growth. Interestingly, the research found that turbulent flow conditions promoted the most prolific growth of Legionella, while stagnant conditions, often associated with dead legs, showed the least growth. The study hypothesized that turbulent conditions increased oxygen and nutrient availability, leading to the proliferation of biofilm and Legionella. Additionally, Lehtola’s 2006 study revealed that flowing water supported bacterial growth more than stagnant conditions, contrary to common belief. Moreover, Sidari’s 2004 research challenged the widely held belief of a direct link between dead legs and Legionella, as the removal of dead legs did not result in a negative Legionella test. These findings highlight the intricate relationship between water flow and Legionella growth. Dead legs in plumbing and Legionella The presence or absence of dead legs is not a reliable predictor for Legionella. While dead legs can negatively impact water hygiene and quality, they may not directly promote Legionella colonization in building water systems. They may, however, indirectly contribute to Legionella growth and risk of disease occurrence. Stagnant water in dead legs can serve as a potential nutrient source and a refuge for Legionella under specific conditions. Dead legs can also create low water flow areas, decrease disinfectant levels, allow the tempering of water, and increase organic load and sediment accumulation which all may increase the likelihood of Legionella colonization. Due to pressure changes in water systems, dead legs may also contaminate or impact the entire water system. Therefore, while a dead leg alone may not reliably predict Legionella, they should still be considered a potential risk factor and addressed in water management strategies to minimize the risk of Legionella growth and transmission. Emphasizing comprehensive understanding There’s merit in maintaining high water hygiene and quality standards, however, a comprehensive understanding of the actual factors leading to Legionella growth is crucial. While a dead leg can be a contributor to Legionella growth, there are other factors such as water flow that could potentially impact Legionella growth, so it’s important to take a holistic approach and look at the entire building water system. References Liu 2006: Effect of flow regimes on the presence of Legionella within the biofilm of a model plumbing system Lehtola 2006: The effects of changing water flow velocity on the formation of biofilms and water quality in pilot distribution system consisting of copper or polyethylene pipes Sidari 2004: Keeping Legionella out of water systems
Legionella and Waterborne Pathogens 101 for Plumbing Engineers
Successful plumbing engineering involves the comprehensive understanding and meticulous control of waterborne pathogens, with a particular focus on Legionella. These harmful pathogens can infiltrate building water systems through various means, such as contaminated water sources or inadequate water treatment. To effectively mitigate the risk of Legionella and other waterborne pathogens, plumbing engineers must possess in-depth knowledge of the specific characteristics of these microorganisms, their transmission routes, and the factors that contribute to their proliferation. By implementing robust water management strategies into their system designs, plumbing engineers play a critical role in safeguarding public health and ensuring the safety of building occupants. Understanding Legionella Legionella is a gram-negative bacterium belonging to the Legionellaceae family, which encompasses more than 60 species and serogroups. Among these, approximately half have been linked to various diseases. Notably, Legionella pneumophila is responsible for over 90% of reported cases of Legionnaires’ disease, a severe form of pneumonia that is contracted through the inhalation and aspiration of water droplets. Legionella growth in building water systems Legionella, a bacterium found naturally in surface and groundwater sources, typically exists in low concentrations in the source water. Legionella and waterborne pathogens can withstand municipal treatment processes and proliferate within building water systems that provide suitable growth factors. Legionella exhibits growth within a specific temperature range, temperatures commonly found in building water systems. Studies show elevated temperatures may reduce the potential for Legionella growth, however, it’s important to consider the impact of factors such as scale, biofilm, and water quality in buildings, as these factors may impact the effectiveness of temperature on Legionella and pathogen growth. Impact of biofilms Biofilms, which are complex communities of microorganisms, consist of cells that adhere to each other and often to a surface. These intricate structures can harbor both pathogenic and non-pathogenic bacteria, creating a diverse and dynamic ecosystem. By providing a protective shield, biofilms enable bacteria to withstand physical forces and disinfection measures, making them resilient and persistent. Moreover, biofilms serve as an ideal breeding ground for bacterial growth, amplification, and recolonization, perpetuating their presence and potential impact. Factors increasing risk Several factors contribute to the increased risk of Legionella and other waterborne pathogen outbreaks in buildings. These factors include the design of complex plumbing systems, which can create stagnant water areas that promote bacterial growth. Additionally, warm water environments provide an ideal breeding ground for pathogens, while increased water age further allows for the accumulation and proliferation of harmful bacteria. Moreover, low disinfection residual levels in the water supply can fail to effectively eliminate these pathogens. It is important to note that construction and renovation events in buildings can introduce additional vulnerabilities, disrupting the plumbing system and potentially exacerbating the risk of outbreaks. Sediment risk and damage Sediment buildup in plumbing systems is an additional risk factor. Sediment can accumulate over time, creating an environment that supports the growth of Legionella and other bacteria. Moreover, sediment can cause corrosion and damage to plumbing equipment, further increasing the risk of bacterial growth and system failure. Methods of Legionella reduction Engineers play a crucial and essential role in managing and reducing the risk of Legionella. By deepening their understanding of the impact of water quality on piping systems and considering Legionella risk during the design phases of building water systems, engineers can effectively implement comprehensive strategies to minimize the risk of Legionella outbreaks. The ASHRAE Standard 188, a widely recognized industry standard, establishes minimum requirements for Legionella risk management in building water systems. This standard provides clear direction and specific requirements for designing and maintaining building water systems that are safe and compliant. By adhering to these guidelines, engineers can ensure the health and well-being of building occupants while effectively mitigating the risk of Legionella contamination. For plumbing engineers, it is crucial to comprehend and regulate waterborne pathogens, such as Legionella. By implementing engineering solutions and performing risk assessments, the potential risk these pathogens pose to water quality and occupants of a building can be greatly diminished.
Legionella Risk Assessment: Essential Information for Building Owners and Managers
Legionella is a type of bacteria that can cause Legionnaires’ disease, a severe form of pneumonia. Unfortunately, Legionella can be found in any building, including hospitals, skilled nursing facilities, hotels, and office buildings. The good news is that there are steps you can take to identify and manage the risks associated with Legionella. What is a Legionella risk assessment? A Legionella risk assessment is a process that identifies the potential for Legionella bacteria to grow and spread through water systems within a building. This assessment should be conducted by an ASSE 12080 Certified Legionella Water Safety and Management Specialist and include: Fill out the form at the bottom of this page to download our Legionella Risk Assessment template for a detailed list of what an assessment should include. Who needs a Legionella risk assessment? Since Legionella can colonize any type of building, all buildings with potable water systems and aerosol-generating systems (such as cooling towers) should conduct a Legionella risk assessment to determine potential risks to building occupants and potential sources of Legionella transmission. This is especially true for hospitals, skilled nursing facilities, office buildings, hotels, and any building with a water system at risk of Legionella contamination. Landlords, building owners, and employers are responsible for protecting their occupants from Legionella exposure. How often do you need to conduct a Legionella risk assessment? Legionella risk assessments should be conducted annually or even more frequently if recommended by a water safety specialist. Additionally, any changes to the building’s water system should trigger a reassessment to address Legionella risks proactively. What are the benefits of conducting a Legionella risk assessment? Regular Legionella risk assessments provide numerous benefits: To ensure the health and well-being of occupants and minimize risk, buildings with water systems must undergo regular Legionella risk assessments. Don’t wait for a Legionella outbreak to occur – contact our ASSE 12080 Certified Legionella Water Safety and Management Specialists to schedule your Legionella risk assessment today. Download: Legionella Risk Assessment Template Fill out the form to download our Legionella Risk Assessment template for a detailed list of what an assessment should include.
Examining the Efficacy of Copper-Silver Ionization for Management of Legionella
MARK LECHEVALLIERAMERICAN WATER WORKS ASSOCIATION (AWWA), WATER SCIENCE, MARCH 2023 IntroductionThis review article examined more than 80 sources of literature and studies related to copper-silver ionization system efficacy, design, maintenance, and operations, and the impact water chemistry has on its performance. ResultsPrevious research indicates that copper-silver ionization is effective for Legionella control. Other key findings of this study include: ConclusionThe report concludes that using copper-silver ionization to control Legionella and other opportunistic pathogens is highly effective when the units are properly designed, maintained, and operated. Full study
Hospitalizations Due to Selected Infections Caused by Opportunistic Premise Plumbing Pathogens and Reported Drug Resistance in the United States Older Adult Population
ELENA N. NAUMOVA, ALEXANDER LISS, JYOTSNA S. JAGAI, IRMGARD BEHLAU, JEFFREY K. GRIFFITHSPALGRAVE MACMILLAN, JOURNAL OF PUBLIC HEALTH POLICY, SEPTEMBER 2016 IntroductionThe study explores the health implications of opportunistic premise plumbing pathogens (OPPP) in US drinking water, particularly focusing on vulnerable populations like the elderly. These pathogens have gained attention due to the Flint Water Crisis, which exposed unresolved social, environmental, and public health issues related to changes in water source and treatment procedures. The study aims to understand the impact of OPPP, such as Legionella pneumophila, Mycobacterium avium, and Pseudomonas aeruginosa, and highlights the need for improved monitoring and prevention. ResultsAnalyzing 108,202 hospitalization records from 1991 to 2006, the study reveals significant findings about OPPP-related hospitalizations among the elderly. Legionella pneumophila resulted in 7,933 cases of Legionnaires’ disease. Pseudomonas aeruginosa and gram-negative anaerobes contributed to 544,643 hospitalizations. Among non-tuberculous mycobacteria (NTM), pulmonary infection caused by Mycobacterium avium-intracellulare totaled 71% of the 48,854 cases. Reported drug resistance was observed in 1.68% of Pseudomonas infections, 1.05% of NTM infections, and 0.6% of Legionnaires’ disease cases. Drug resistance led to a 32.8% increase in Medicare charges. The estimated cost of Pseudomonas infections was $8.8 billion USD over 15 years, with a per-case differential payment of $14,510 for resistant cases. ConclusionThe study highlights a substantial economic burden of OPPP-related hospitalizations in the elderly, with antibiotic resistance significantly impacting costs. There is an urgent need for enhanced identification, reporting, and prevention strategies for these pathogens in premise plumbing systems. The authors emphasize the importance of interdisciplinary collaboration and increased efforts in monitoring and regulatory measures to address the growing issue of OPPP infections. The study underscores the need for comprehensive research to mitigate the health risks posed by these pathogens in drinking water. Full study
Controlling Legionella in Hospital Drinking Water: An Evidence-Based Review of Disinfection Methods
YUSEN LIN, JANET E. STOUT, VICTOR YUCAMBRIDGE UNIVERSITY PRESS, INFECTION CONTROL AND HOSPITAL EPIDEMIOLOGY, FEBRUARY 2011 IntroductionThis study reviewed the efficacy of different disinfection methods for controlling Legionella in hospitals, including copper-silver ionization, chlorine dioxide, hyperchlorination, monochloramine, UV, point-of-use filtration, and superheat-and-flush. The four criteria each disinfection method must meet to validate efficacy include: ResultsA summary of findings for each disinfection method is included below. Copper-silver ionization– Only method validated by the four criteria– Easy installation and maintenance– Not impacted by higher temperatures– Residual levels are maintained for a prolonged period– Efficacy declines in pH greater than 8.5 Chlorine dioxide– Penetrates biofilm– Effective over a wide range of pH levels– Creates harmful byproducts– Difficult to maintain residual levels Monochloramine– Penetrates biofilm– Effective over a wide range of pH levels– Can cause anemia in dialysis patients– On-site generation can be complicated Hyperchlorination– Most expensive and unreliable of all methods– Causes corrosion– Does not penetrate biofilm– Introduces carcinogens into the water Point-of-use filtration– Effective against Legionella and Mycobacterium– Provides immediate protection making them a good option for outbreaks– Not cost-effective for long-term use UV– Non-chemical– Works best when installed on the incoming water supply– Does not provide systemic disinfection Superheat-and-flush– Effective in emergencies– Not effective for prolonged use– Limited to hot water lines ConclusionThere are several viable methods for controlling Legionella, but copper-silver ionization was the only method validated by the four criteria at the time of this study. The researchers concluded that “copper-silver ionization appears to be the best available technology today for controlling Legionella colonization in hospital water systems.” They suggested that rigorous maintenance plans, regular monitoring of ion concentrations, and frequent Legionella testing are necessary to ensure long-term success. Full report
Intermittent Use of Copper-Silver Ionization for Legionella Control in Water Distribution Systems: A Potential Option in Buildings Housing Individuals at Low Risk of Infection
ZEMING LIU, JANET E. STOUT, MARCIE BOLDIN, JOHN RUGH, WARREN F. DIVEN, VICTOR L. YUOXFORD ACADEMIC, CLINICAL INFECTIOUS DISEASES, JANUARY 1998 IntroductionThis study evaluated three healthcare facilities colonized with Legionella to determine if: ResultsThe Legionella positivity rate (percentage of test sites positive for Legionella) was significantly reduced for the two test buildings using copper-silver ionization. Both test buildings remained Legionella-free for six to eight weeks after deactivating the copper-silver ionization system. The researchers found high concentrations of copper in the biofilm and suggested this to be the reason that early recolonization of Legionella was prevented. ConclusionBecause copper-silver ionization provides a residual effect of preventing early recolonization of Legionella, it is possible to rotate one copper-silver unit between several buildings. The study explained that this method could be considered for facilities that house individuals at low risk for contracting Legionnaires’ disease. Full study
Experiences of the First 16 Hospitals Using Copper-Silver Ionization for Legionella Control: Implications for the Evaluation of Other Disinfection Modalities
JANET E. STOUT, VICTOR L. YUCAMBRIDGE UNIVERSITY PRESS, INFECTION CONTROL AND HOSPITAL EPIDEMIOLOGY, AUGUST 2003 IntroductionThis study examined 16 acute care hospitals using copper-silver ionization as a disinfection method. Surveys were deployed in 1995 and 2000 to gather information from each hospital. The 2000 survey was up to 11 years after installation for some hospitals. ResultsBefore installing a copper-silver ionization system, all 16 hospitals had reported cases of hospital-acquired Legionnaires’ disease. Seventy-five percent had tried other disinfection methods, including superheat-and-flush, ultraviolet light, and hyperchlorination. After installing a copper-silver ionization system, no cases of hospital-acquired Legionnaires’ disease were reported, and the Legionella positivity rate (percentage of test sites within the hospital positive for Legionella) was significantly reduced. The study found that the infection control practitioners rated the disinfection system as “excellent.” The engineers rated the operation and maintenance of the system as “average” (not easy, but also not difficult). ConclusionThe team behind this study developed a standardized, evidence-based approach to assist hospitals with evaluating different disinfection methods. The four criteria a disinfection method must meet include the following: At the time of this study, copper-silver ionization was the only disinfection modality to have fulfilled all four evaluation criteria. Full study
