December 22, 2005

Chlorine kills bugs living in hospital water

By Deborah Mitchell

WASHINGTON (Reuters Health) - Chlorine dioxide can be
safely used to remove Legionella and other water-borne
pathogens from a hospital's water supply, researchers reported
recently at the 45th Interscience Conference on Antimicrobial
Agents and Chemotherapy.

Before disinfection, L. pneumophila, the bacteria that
cause Legionnaires' disease, was detected in 57 percent of
water samples at their hospital. After disinfection with
chlorine, levels dropped to 10 percent. There have also been no
new cases of Legionella-related hospital-acquired (nosocomial)

Chlorine dioxide is not a new chemical, Dr. Janet E. Stout
of the VA Medical Center in Pittsburgh Stout pointed out to
Reuters Health. "It has been used in the treatment of pulp and
paper water -- but on the large-scale it has some health and
safety issues." High levels of the byproducts of this chemical
have been associated with increased risk of miscarriage and,
like chlorine, an increased risk of cancer.

"The Environmental Protection Agency sets maximum amounts
(of chlorine dioxide) that can be in drinking water. We set out
to see if chlorine dioxide used to remove pathogens from the
water exceed this level -- and the answer is no," Stout said.

The EPA maximum water levels of chlorine dioxide and
chlorite are 1.0 mg/L and 0.8 mg/L, respectively, she
explained. Hospital water samples evaluated every 2 months
between June 2004 and November 2005 from 17 sites showed that
chloride dioxide levels were well beneath the EPA cut-off.

Disinfecting the water with chlorine led to a significant
reduction in Legionella colonization and no cases of
hospital-acquired Legionnaire's disease were diagnosed, Stout
said. They also observed a reduction in levels of total
bacteria after the chlorine system was installed.

"This is our third field evaluation -- so we're generating
information for other hospitals to accurately evaluate whether
this is truly going to be something that works for them," she

Hospital-acquired legionellosis "is basically very
widespread across the United States and the world," and it's
not just immunocompromised patients who are affected, Stout
added. For example, patients going in for cardiac or other
major surgery are also susceptible.

"But now we have another tool to combat it," she concluded.