By Joseph S. Cervia, MD, MBA, FACP, FAAP, FIDSA
Healthcare-associated infections (HAIs) affect an estimated 1.7 million individuals and result in 99,000 deaths annually in American hospitals. With its role in handwashing accepted as perhaps our most reliable means for reducing HAI risk, hospital tap water has also been recognized as a source of such infections. Peer-reviewed literature has demonstrated that hospital tap water contains microbial pathogens, and that biofilm in water systems resists disinfection and delivers pathogenic organisms to the point of care. At-risk patients are susceptible to infection through direct contact, ingestion, and inhalation of waterborne pathogens. Systemic water treatment technologies reduce levels of recognized waterborne pathogens; however, they cannot eradicate biofilm within healthcare facility plumbing. Existing point-of-use (POU) filtration technologies have been reported to interrupt clinical outbreaks of infection due to recognized waterborne pathogens in the healthcare environment, and can represent a critical component of a comprehensive infection control strategy, particularly when targeted for patients at high risk.
According to the Centers for Disease Control and Prevention (CDC), HAIs account for an estimated 1.7 million infections and 99,000 deaths annually in American hospitals.(1) It has long been accepted that handwashing with water may be the most reliable defense in the battle to reduce HAIs; however, hospital tap water has also been recognized paradoxically as a source of risk for such infections. Navigating the turbulent seas of healthcare payment reform and safeguarding precious resources requires an awareness of these risks and how they may be safely and cost-effectively managed. What follows are eight facts healthcare leaders must know in order to stay afloat.
1. Waterborne HAIs are alarmingly common.
In the wake of what has been described as one of the deadliest outbreaks of Legionnaires’ Disease (LD) ever reported, one of the 127 recognized victims, which included patients, employees, and visitors initiated a $600 million class-action lawsuit against the nursing facility at the center of the storm.(2) A separate 2006 LD outbreak at an acute care facility, which also killed and injured both patients and visitors alike, resulted in a $5.2 million settlement.(3) Yet another institution, a renowned university teaching hospital, has for years been plagued by repeated lawsuits related to LD contracted from its water system.(4-5) According to experts, healthcare-associated LD nationwide is simply not that unusual.(6) According to the CDC, an estimated 8,000 to 18,000 cases of LD occur each year in the United States. This is particularly striking as the agency also notes that only 2 percent to 10 percent of estimated LD cases are reported.
2. Waterborne HAIs exact a devastating human and financial toll.
Most LD cases are sporadic; 23 percent are nosocomial and 10 percent to 20 percent can be linked to outbreaks. Death occurs in 10 percent to 15 percent of LD cases; and, a substantially higher proportion of fatal cases occur during nosocomial outbreaks. Disease is often attributed to inhalation of contaminated aerosols from showers and faucets, and aspiration of contaminated water. Nevertheless, in normal hosts, bacterial exposures from such water sources are typically cleared by innate defenses, such as the respiratory tract’s mucociliary escalator for elimination of inhaled organisms.(7) However, immunocompromised individuals, such as pharmacologically immunosuppressed recipients of bone marrow and solid organ transplants, persons with congenital or acquired immunodeficiency syndromes, oncology and burn patients, critically ill patients in intensive care units, smokers, individuals with chronic cardiac and respiratory disorders, and residents of skilled nursing facilities are likely to be at higher risk for LD and infections with other waterborne pathogens (WBP). It is precisely for such at-risk patients that appropriate infection control measure are most important.
Since the causative bacterium, Legionella pneumophila will not grow in routinely utilized culture media, LD has been remarkably under-diagnosed. Nevertheless, urinary antigen, direct fluorescent antibody, and culture-based testing for LD have been available to and utilized by clinicians for many years, and enhanced detection methods such as rapid duplex polymerase chain reaction (PCR) testing have been more recently developed. Despite the likelihood of under-diagnosis, Medicare data presented in the Federal Register indicate that for fiscal year 2007, 351 cases of LD were diagnosed in beneficiaries at a cost of $86,014 per hospital stay.
3.The costs of HAIs are progressively being shifted to providers.
Whereas historically such additional treatment costs have been shifted to payors, with current trends in U.S. healthcare payment reform, it is likely that this burden will be increasingly borne by hospitals. Considering the aforementioned estimates, savings for prevention of LD in Medicare beneficiaries alone would be estimated to be over $30 million per year, substantially higher than that for other healthcare-associated conditions (e.g., air embolism, blood incompatibility, and surgical site infection after coronary artery bypass grafting) recently selected by the Centers for Medicare and Medicaid Services (CMS) in its 2008 Final Rule for exclusion from additional hospital reimbursement. Acknowledging these data, CMS is continuing to consider healthcare-associated LD and infections attributable to other WBP in its subsequent rulemaking.(8)
4. A startling number of HAIs may be attributed to WBPs.
Indeed, while LD outbreaks in healthcare facilities often command headlines, clinicians struggle with other WBP, such as Pseudomonas aeruginosa, Stenotrophomonas maltophilia, and Acinetobacter spp. among many others on a daily basis in their hospitalized patients. In fact, some of the most frequently isolated Gram-negative bacteria have been found to persist in hospital water for extended periods and have been responsible for nosocomial outbreaks.(9) A recent review of prospective studies published between 1998 and 2005 indicated that between 9.7 percent and 68.1 percent of random intensive care unit water samples were positive for P. aeruginosa, and between 14.2 percent and 50 percent of patient infections with this organism were due to genotypes found in intensive care unit water.(10)
According to the CDC, the overall incidence of P. aeruginosa infections alone in U.S. hospitals averages about 0.4 percent (4 per 1,000 discharges), and the bacterium is the fourth most commonly isolated nosocomial pathogen accounting for 10.1 percent of all hospital-acquired infections.(11) In fact, up to 42 percent of P. aeruginosa infections in hospitalized patients have been linked to water;(12-13) and one investigation has estimated that 1,400 deaths occur each year as a result of waterborne nosocomial pneumonias attributable to P. aeruginosa alone.(8)
All of these infections result in huge costs to our healthcare system, as well as a tremendous human toll in excess morbidity and mortality. Moreover, numerous clinical studies published in peer-reviewed medical literature demonstrate the clinical efficacy and cost-effectiveness of regular water testing, appropriate systemic water disinfection, and POU hospital water filtration as a comprehensive strategy for reducing infections with Legionella and other WBP in hospitals.(14) CDC, the World Health Organization (WHO), the Occupational Safety and Health Administration (OSHA), the Veterans Health Administration (VHA), and other recognized standards organizations have established guidelines for the prevention of LD and other WBP that have been available and widely distributed for years.(15-22) Yet, tragically, many healthcare facilities fail to establish effective prevention strategies, exposing patients and their institutions to unnecessary risk.
5. WBP risk may be astonishingly difficult to detect.
Despite concerns regarding the increasing incidence of serious HAI due to multi-drug resistant Gram-negative pathogens, the risk of waterborne transmission of these microbes has received relatively little attention. Dr. Bruce Dixon, director of the Allegheny County Health Department has summed up the problem succinctly: “If you don’t look for it, you won’t find it. If you don’t find it, you don’t think you have a problem. If you don’t think you have a problem, you don’t do anything about it.”(23)
Even when healthcare facilities do look, a better understanding of the ecology of WBP in the healthcare environment is necessary in order to gain further insight into why this risk may go largely unrecognized. Waterborne microbes thrive to varying degrees in both hot and cold water. Yet, whereas cold water is delivered directly to the POU (e.g., taps, showers), hot water in large buildings such as hospitals is supplied via a recirculation loop, which contains organic and inorganic nutrients to nourish waterborne microbes, maintains favorable temperatures for microbial growth, and promotes the formation of biofilm on internal surfaces of pipes and fixtures. Waterborne microbes may be shed from biofilm only intermittently, complicating efforts at detection. Moreover, WBP, adapted to life in a relatively nutrient-poor environment, may be difficult to culture using nutrient-rich media for short incubation periods (e.g., 24 to 48 hours at 37 degrees C) as is standard practice for the culturing of specimens obtained from patients by clinical microbiology laboratories. Successful culturing of Legionella and other WBP may require special media and extended incubation periods at lower temperatures (e.g., 20 degrees C for 14 to 28 days).(24)