The Importance of Controlling Legionella Bacteria in Ice Machines

By: Lyanne Claudio  ASSE 12080 Legionella Water Safety and Management Specialist

Since the identification of Legionella bacteria in 1976 after a deadly outbreak following an American Legion convention in Philadelphia , multiple studies have found Legionella bacteria growing in ice machines[1]. Even more concerning, there have been several Legionnaires’ disease cases in hospitals linked to ice machines[2][3].

In a study published in 2008 by Schuetz et al., cultures of environmental samples taken from an ice machine at a bronchoscopy suite of a healthcare facility revealed that the ice machine was contaminated with Legionella pneumophila serogroup 8. Legionella pneumophila isolates recovered from the patient’s clinical samples were also identified as L. pneumophila serogroup 8. This led to the discovery that patients were exposed to the bacteria due to a process that involved immersing uncapped syringes of sterile saline in contaminated ice baths. At least one of the patients contracted legionellosis. Fortunately, future cases were prevented by performing extensive cleaning of the ice machine and a replacement of the ice machine water filter[4].

Legionella bacteria experience rapid growth in warm temperatures (77°F-108°F); however, Legionella remain dormant but viable in temperatures under 68° F. Heat from compressors inside ice machines can warm the incoming water into temperatures favorable for Legionella growth. If water or ice containing Legionella bacteria is then aspirated by an immunocompromised patient, the bacteria can multiply when introduced to the patient’s lungs.

Due to the substantial risk of Legionella and other waterborne pathogen proliferation in ice machines, facility managers must consider regular cleaning and disinfection of internal ice machine components. Most ice machine manufacturers recommend these components be cleaned at least twice per year. In addition to routine sanitization of ice machines, one study by Querry et al. (2017) found that ice machines in a healthcare facility with small micron point of use filters had a lower colonization rate of Legionella. The study concluded that in addition to routine sanitization procedures, continuous supplemental disinfection with monochloramine was the most effective and easiest to maintain strategy for preventing Legionella bacteria colonization in the ice machines[5].

Ice machines must be part of a complete water safety plan. Contact Barclay Water Management to schedule an ice machine cleaning at your facility today. Our Environmental Group is professionally trained to identify risk, sanitize ice machines, provide detailed cleaning reports and validation testing.

[1] Stout, J., Yu, V., & Muraca, P. (1985). Isolation of Legionella pneumophila from the Cold Water of Hospital Ice Machines: Implications for Origin and Transmission of the Organism. Infection Control, 6(4), 141-146. doi:10.1017/S0195941700062937

[2] Bencini, M. A., Yzerman, E. P., Koornstra, R. H., Nolte, C. C., den Boer, J. W., & Bruin, J. P. (2005). A case of Legionnaires’ disease caused by aspiration of ice water. Archives of environmental & occupational health60(6), 302–306.

[3] Graman PS, Quinlan GA, Rank JA. Nosocomial legionellosis traced to a contaminated ice machine. Infect Control Hosp Epidemiol. 1997;18(9):637-640. doi:10.1086/647689

[4] Schuetz AN, Hughes RL, Howard RM, et al. Pseudo-outbreak of Legionella pneumophila serogroup 8 infection associated with a contaminated ice machine in a bronchoscopy suite. Infect Control Hosp Epidemiol. 2009;30(5):461-466. doi:10.1086/596613

[5] Ashley Querry, BS, CIC, Anthony Pasculle, ScD, Edward Dudek, MPPM, Joseph Crouse, BS, Alex Sundermann, BS, MPH, Leon Young, BS MT, Janina-Marie Tatar, MT (ASCP), Alex Troesch, Certificate in Heating and Air Conditioning, Eric Meduho, Safety Specilist, Julia Wozinak, BA, MA, Carlene Muto, MD, MS, FSHEA, Legionella Colonization Prevention in Ice Machines, Open Forum Infectious Diseases, Volume 4, Issue suppl_1, Fall 2017, Pages S228–S229,

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