Legionella Articles

Legionellosis: United States, 2000-2009

"Reported legionellosis incidence rates increased nearly threefold during 2000--2009. In 2009, NNDSS received 3,522 case reports, the most since legionellosis became a reportable disease in 1976. Increased rates were observed across all age groups and geographic regions. The reported case totals likely underestimate the actual disease burden; the most recent completed U.S. population-based pneumonia etiology study estimated that 8,000-18,000 persons are hospitalized each year with LD."

Morbidity and Mortality Weekly Report (MMWR)
August 19, 2011

"Environmental Culturing for Legionella:Can we build a better mousetrap?"

This report discusses best practices for Legionella detection in water systems and reviews guidelines for Legionella prevention.  The direct link between drinking water colonization by Legionella and hospital-acquired legionellosis has prompted healthcare organizations to recommend proactive culturing for Legionella as a preventative measure (see guideline table).

American Journal of Infection Control
June 2010

The Department of Veterans Affairs became the first U.S. organization to establish a national Legionella policy for the prevention of hospital-acquired Legionnaires’ disease that included the collection of environmental samples for Legionella testing as part of an annual Legionella Risk Assessment. 

VHA DIRECTIVE 2008-010 was distributed in February 2008 to more than 250 VA facilities nationwide.  The Directive is based on the Allegheny County Health Department (ACHD) Guideline for the Prevention and Control of Legionella Infections in Healthcare Facilities - published in 1993.  Dr. Victor Yu was the primary architect of the ACHD guidelines, and his work on the detection and control of hospital-acquired Legionnaires’ disease was the foundation for the guidelines.  The Allegheny County guidelines can be printed from www.legionella.org

VHA Directive 2008-010 - Prevention of Legionella Disease
February 11, 2009

"Environment of Care Leader," a publication from Decision Health (www.decisionhealth.com), describes the outbreak and reviews prevention tactics used by healthcare facilities to combat Legionnaires' disease.

3 Patients in N.J. Hospital Die After Legionnaires’ Outbreak
Vol. 14, No. 19
November 10, 2008

New data presented by the Centers for Disease Control and Prevention indicates that there has been a significant increase in the number of cases of pneumonia caused by Legionella bacteria (legionellosis).  The analysis showed that the number of reported cases increased by 70% since 2002.  

"Public health professionals should focus increased attention on detection and prevention of this important and increasing public health problem."

Increasing Incidence of Legionellosis in the United States, 1990–2005: Changing Epidemiologic Trends
CID 2008:47
September 2008

This article addresses the activities of advisory groups in dealing with Legionella, including The American Society of Heating, Refrigerating and Air Conditioning Engineers (ASHRAE) and the Cooling Technology Institute (CTI).

"Major corporations in America are confronting the legionellosis issue more seriously because of greater awareness that there could be a problem and recent high-dollar lawsuits."

Legionella: An Invisible Risk
Reprinted with permission from CEP (Chemical Engineering Progress)
April 2008

What is the significance of  “viable but non-culturable (VBNC) bacteria in water which can be detected by molecular probes and by physiological activity?  The VBNC state has been demonstrated for Salmonella, Shigella, Vibrio and Legionella pneumophila.  The article by Rebecca Smith and colleagues provides concrete evidence that these VBNC bacteria may not pose a threat as a hidden reservoir of infectious disease.   

Alive But Not Infectious
THE LANCET Infectious Diseases

We performed Legionella testing as part of a multi-center study at VA facilities. The results were published in the Journal of Infection Control and Hospital Epidemiology.

Role of environmental surveillance in determining the risk of hospital-acquired legionellosis: a national surveillance study with clinical correlations
Stout JE, Muder RR, Mietzner S, Wagener MM, et al.

CONCLUSION: Environmental monitoring followed by clinical surveillance was successful in uncovering previously unrecognized cases of hospital-acquired Legionella pneumonia.

Infect Control Hosp Epidemiol. 2007 Jul;28(7):818-24

This article discusses the role of environmental surveillance in the prevention of hospital-acquired Legionnaires' disease and calls for multi-center studies to explore the relationship between Legionella colonization and disease.

Surveillance of hospital water and primary prevention of nosocomial legionellosis: what is the evidence?
O'Neill E, Humphreys H.
J Hosp Infect. 2005 Apr;59(4):273-9.

CONCLUSION:  Centres with transplant units or other patients with significant immunosuppression should, in the interim, consider routine sampling for legionella in hospital water in addition to other control measures. Therefore, infection control teams must work closely with hospital engineering and technical services departments and hospital management, as
well as ensuring that physicians and others have a heightened awareness of hospital-acquired legionellosis.