Legionella Guidelines

VIEW THE LEGIONELLA GUIDELINES TABLE.

Healthcare

The Allegheny County Legionella Guideline - 1993

The United States has lagged behind our European counterparts in producing engineering and water treatment standards designed to protect building occupants from the risk of Legionellosis in water systems. The earliest guidance document in the U.S. was produced in 1993 by the Allegheny County Health Department (ACHD), Pittsburgh, Pennsylvania.  Numerous hospitals were experiencing outbreaks of Legionnaires’ disease and the Centers for Disease Control & Prevention (CDC) approach of postponing environmental monitoring until after cases had occurred was deemed inadequate.  A more proactive approach was needed and the ACHD guideline filled that void by recommending that healthcare facilities culture their water systems BEFORE cases of Legionnaires’ disease were diagnosed in their hospitals.

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The Veterans Affairs Legionella Directive -2008

One of the largest healthcare systems in the U.S. is the Veterans Healthcare System, comprised of over 150 healthcare facilities.  In 2008, the VHA issued their own Legionella prevention guidance document – VHA DIRECTIVE 2008-010 Prevention of Legionnaires’ Disease. This directive is based on the ACHD guideline.  The CDC guidelines were deemed to be “arguably out-of-date” and the VA determined that it should strive to exceed the CDC standards.  This guideline requires annual Legionella risk assessments that includes environmental cultures for Legionella.

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The Centers for Disease Control & Prevention

The CDC document “Guidelines for the Prevention of Healthcare-associated Pneumonia” was published in 2004 and describes the approach to prevention of healthcare acquired Legionnaires’ disease.  This document concedes that environmental culturing of the hospital water system can performed as part of a comprehensive strategy to prevent Legionnaires’ disease in transplant patients. Facilities with hemopoietic stem-cell- and/or solid-organ--transplantation programs, periodic culturing for legionellae in water samples from the transplant unit(s) can be performed as part of a comprehensive strategy to prevent Legionnaires disease in transplant recipients.

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Guidance Documents and Water Treatment Guidelines

There are Legionella standards that are legally enforceable documents in the United Kingdom as well as Australia and many other countries.  Many of these documents include culturing for Legionella as an integral part of the prevention plan.  See the links in the table to view some of these documents.  The Australian New Zealand guideline is particularly useful in that it presents a very pragmatic approach to cooling tower maintenance.  Actions are recommended based on concentration-based targets from Legionella concentrations from periodic cultures.

In the absence of a cohesive national approach to prevention, professional organizations have produced their own guidelines.  These organizations include the Association of Water Technologies, the Cooling Technology Institute, the American Society for Heating, Refrigeration and Air-conditioning Engineers. 

VIEW THE LEGIONELLA GUIDELINES TABLE