Special Pathogens Laboratory sets the industry standard for Legionella control through our introduction and evaluation of disinfection technologies. Since the early 1990s, we have tested all major Legionella disinfection technologies used in the field and continue to explore new technologies. Our findings are published in peer-reviewed scientific and medical journals. SPL validates the efficacy of disinfection methods for Legionella in water systems using a step-wise evaluation criteria. Our approach is published in the Experiences of the First 16 Hospitals Using Copper-silver Ionization: Implications for the Evaluation of Other Disinfection Modalities (2003).

Following are disinfection technologies shown to effectively reduce the presence of Legionella in water systems:


Sanipur Monochloramine

Monochloramine has been used successfully for municipal water treatment. An onsite monochloramine generation system for treatment of single buildings was developed by Sanipur (Brescia, Italy). The results showed a significant decrease in Legionella percent positivity of the hospital's hot water system soon after installation. Dr. Stout presented findings of the first U.S. study of this monochloramine generating system for Legionella disinfection at the annual Association of Water Technologies conference in September 2012.

After monitoring the system for a total of 29 months, results showed consistent efficacy and appears in the November issue of Infection Control and Hospital Epidemiology (available online).

Evaluation of a New Monochloramine Generation System for Controlling Legionella in Building Hot Water Systems. Scott Duda, MS; Sheena Kandiah, MD, PhD; Janet E. Stout, PhD; Julianne L. Baron, BS; Mohamed Yassin, MD, PhD;  et al.  Infection Control and Hospital Epidemiology; November 2014, Vol. 35, No. 11.

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SPL presented two posters on monochloramine in October 2013 at the Eighth International Conference on Legionella in Australia

Monochloramine Disinfection of a Hospital Water System for Preventing Hospital-Acquired Legionnaires' Disease: Lessons Learned from a 1.5 Year Study presented more data of the first US field study of a monochloramine generating system in a hospital hot water system. The conclusions show monochloramine to be a promising disinfectant for Legionella.

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Use of Pyrosequencing to Determine the Effects of Monochloramine Treatment on Legionella and Associated Bacterial Populations in a Hospital Hot Water System is the first US study to assess changes in Legionella and microbial flora due to chloramination in a hospital's hot water system using next generation sequencing. This study shows a strong reduction in Legionella presence and a lack of many issues with chloramination found in municipal water supplies.

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Copper-Silver Ionization

Copper and silver ions are bactericidal against Legionella and other waterborne pathogens. A study by Dr. Janet E. Stout and Dr. Victor L. Yu, published in Infection Control and Hospital Epidemiology, documents that copper-silver ionization significantly reduced Legionella in hot water distribution systems of 16 hospitals, and reduced or eliminated cases of hospital-acquired Legionnaires' disease.

Experiences of the First 16 Hospitals Using Copper-Silver Ionization for Legionella Control: Implications for the Evaluation of Other Disinfection Modalities. Janet E. Stout, PhD; Victor L. Yu, MD. Infection Control and Hospital Epidemiology; Aug. 2003: Volume 24, No. 8.

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Chlorine Dioxide

Research conducted by Special Pathogens Laboratory showed that Legionella can be successfully controlled by chlorine dioxide. The time needed to achieve requisite reduction in percent positivity is site specific and dependent on whether the application point is on the cold water, hot water or a combination.

Prospective study of the safety and efficacy of chlorine dioxide for Legionella control in a hospital water system.  Zhang Z, McCann C, Stout JE, et al.  Infection Control and Hospital Epidemiology. 2007; 28(8).

Point-of-Use Filters

Special Pathogens Laboratory and others have shown in independent studies that Point-of-Use (POU) filters prevent exposure to waterborne pathogens from faucets, showers and ice machines. These pathogens include Legionella, Pseudomonas and Mycobacteria.

Efficacy of new point-of-use water filter for preventing exposure to Legionella and waterborne bacteria. Sheffer PJ,  Stout JE, Wagener MM, Muder RR. Am J Infect Control. 2005 Jun;33(5 Suppl 1):S20-5.

Ultraviolet Light

Research by Special Pathogens Laboratory showed that focal disinfection with UV light could reduce Legionella in a hospital when combined with a systemic disinfection method.

Legionella in Water Distribution Systems. Lin YS, Stout JE, Yu VL, Vidic RD. Semin Respir Infect. 1998 Jun;13(2):147-59. Review.