Researchers urge filtration to halt hospital waterborne pathogens
PITTSBURGH, Pa.—Following a recent study on prevention of pathogens in healthcare facility water systems, Janet Stout, Ph.D., director of special pathogens laboratory at the Veterans Administration (VA) Healthcare System, is urging hospitals to consider point-of-use filtration to eliminate waterborne infections such as Legionella.
Dr. Stout's study, conducted at the VA facility here, found that a 0.2-µm Aquasafe Water Filter from Pall Corp. (www.pall.com) completely eliminated Legionella and achieved a greater than 99 percent reduction in heterotrophic bacteria in water samples. A host of harmful microorganisms can contaminate faucets, taps and showers in hospital and other water supplies, and, while not harmful to healthy people, can be dangerous to anyone with compromised immune systems—cancer and HIV/AIDS patients, transplant recipients, burn victims, the elderly and newborns.
"Approximately 18,000 cases of Legionnaires occur annually," reports Dr. Stout, "and 25 percent of these are acquired from hospital water systems. If you do the math, 39,000 lives have been lost since 1983 due to this bacterium alone. These infections are preventable. We know that if you control the source, you control the disease."
Point-of-use filtration, such as Pall Corp.'s Aquasafe Water Filter, has been found to eliminate Legionella and other life-threatening bacteria and mold from a hospital's potable water supply.
Legionella is just one of several waterborne bacteria that can cause hospital-acquired infections resulting in significant cases of death. Nearly 1,400 deaths occur annually as a result of nosocomial (hospital-acquired) pneumonias caused by waterborne Pseudomonas aeruginosa bacteria. According to Dr. Stout, this bacteria causes approximately 15 percent of all hospital-acquired infections and 25 percent of infections in the ICU.
During her research at the VA Pittsburgh Healthcare System, Dr. Stout looked at a potable water supply that was colonized with Legionella pneumophilia: 594 water samples were collected from seven faucets (four with point-of-use filters), both immediately and after a one-minute flush every two to three days for one week. The cycle was completed for 12 weeks.
At a recent symposium during the Association for Professionals in Infection Control and Epidemiology annual conference, Dr. Stout said that hospitals can proactively eliminate the source of waterborne pathogens—especially in transplant units and ICUs—through water system disinfection, either system-wide or point-of-use. While the Centers for Disease Control and Prevention (CDC) stipulates that water in areas housing transplant patients should not contain Legionella bacteria, Dr. Stout acknowledges, "This strict limit is difficult to achieve with systemic disinfection, so an alternative may be point-of-use filtration."
Also during the symposium, Dr. Elias Anaissie, director of supportive care at the Myeloma Institute for Research and Therapy, the University of Arkansas for Medical Sciences, noted that dangers of waterborne pathogens are not limited to bacteria. Life-threatening mold infections, especially in immune-compromised patients, are now also linked to water sources. Molds were once thought to arise from contaminated outdoor air that infiltrated a hospital's ventilation system, but even with widespread use of high-efficiency air filtration, mold infections continued.
"Water systems worldwide have been shown to be colonized with pathogenic molds," reports Dr. Anaissie. In his own research, Dr. Anaissie found that molds colonize in hospital water distribution systems, become part of the system's biofilm and lead to exposure via spore aerosolization in patient care areas.
In urging awareness among hospital professionals, the researchers note that France and Germany have issued directives that 0.2-µm point-of-use water filters are to be used wherever immune-compromised patients are present. Currently, Florida, Missouri, California, Pennsylvania and Illinois are considering legislation that calls for hospitals to alert the public to their infection rates. In addition, the Consumers' Union is conducting a nationwide campaign to raise awareness of nosocomial infections and to lobby for legislative action.