Legionella bacteria prove difficult to kill

Strains can remain dormant for years while there is no disinfection method guaranteed to work

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Legionella, the shifty bacterium that causes Legionnaires' disease, is tough to find and even tougher to destroy once it colonizes inside hotel, nursing homes or hospital plumbing systems.

It can remain dormant for years, waiting for a dip in disinfectants or ideal water temperatures to emerge and infect people with an aggressive form of pneumonia. The water-borne bacterium thrives in biofilm (slime) and is best transmitted in the aerosol mists of showers and hot tubs.

The elusive characteristics of Legionella were tragically apparent in the 2011-12 outbreak in the Veterans Affairs Pittsburgh Healthcare System, with up to six deaths and 16 veterans infected at the University Drive facility in Oakland.

Identifying, reporting and resolving the outbreak has become the goal of congressional hearings and federal bills to require veterans hospitals -- as required of other hospitals -- to report infections to local, state and federal health departments.

Ali Sonel, chief of staff for VA Pittsburgh, said the strain of Legionella that caused the outbreak was the same strain that caused an outbreak in the 1980s at the University Drive hospital. VA hospital officials found the strain in a remote area of plumbing but thought it too distant to cause the recent outbreak. Further investigation revealed it to be the source of the infections.

"What we have in the facility is Legionella that never entirely goes away," Dr. Sonel said.

He made his comments Thursday during an educational session at the United Cerebral Palsy building in Swissvale, sponsored by the Jewish Healthcare Foundation and Allegheny County Health Department. About 80 representatives, mostly from healthcare organizations, attended the session to learn ways to test, monitor and eradicate Legionella in building plumbing, only to learn that goal remains elusive.

Standards and strategies are lacking, with evidence that infections continue rising nationwide.

The U.S. Centers for Disease Control and Prevention cites an incidence rate of more than 1 case per 100,000 in the U.S. -- more than double the rate of 10 years ago, with the incidence rising annually.

Jim Lando, acting director of the county health department's office of epidemiology and biostatistics, said confirmed cases in Allegheny County have fluctuated, from a recent low of 54 last year to 118 in 2008. To date this year, 71 cases have been reported, with the five-year total approaching 500. The number of Legionella deaths is unknown, he said.

Legionella concentrations form in stagnant water or dead-end areas of plumbing. While the focal concern is public buildings, due to the potential for major outbreaks, Legionella can exist in any plumbing system, including homes. The bacterium thrives in water temperatures of 77 to 108 degrees Fahrenheit.

Along with shock chlorination, VA Pittsburgh is using a heat-and-flush method in which water is heated to 140 degrees before being flushed through the plumbing, with the goal of maintaining at least 124 degrees as it courses throughout water pipes. Other methods involve the use of monochlorination, chlorine dioxide and copper and silver ionization. Officials agree that each method has advantages and disadvantages, but none is guaranteed to work.

Legionnaires' disease and the bacterium got their names from the 1976 outbreak in which 221 cases resulted from an American Legion Convention in Philadelphia, with 34 deaths. The source of Legionella eventually was traced to the hotel's rooftop water cooling tank.

The Jewish Healthcare Foundation convened the educational session to discuss a regional strategy against Legionnaires' disease with a goal of prevention in the wake of the VA Pittsburgh outbreak.

Allegheny County has standards to report and control Legionella, but state or national standards don't yet exist for plumbing systems. Guidelines for analyzing systems to monitor Legionella levels in heating and cooling systems are in the works.

"This is a meeting this community should be having," said Karen Wolk Feinstein, president and CEO of the Jewish Healthcare Foundation. "This is another infection that has a life of its own and therefore, it is likely to require a solution of its own.

"We are obligated to stop what we are doing and figure out how to stop the loss of life from Legionnaires' disease," she said.

neigh_city - region - health

David Templeton: dtempleton@post-gazette.com or 412-263-1578.


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