Legionnaires’ disease in LTC facilities: A hidden threat
By Yu, Victor L | |
Proquest LLC |
Proposed standard recommends stronger safeguards
In the summer of 2013, the
For most people, Legionnaires' disease is something from the history books, a vague memory of
A LITTLE BACKGROUND
Legionnaires' disease-clinically known as legionellosis-is a form of pneumonia caused by waterborne bacteria of the genus Legionella. It carries a mortality rate of 40 percent when acquired in hospitals.
More than 50 species and subspecies of Legionella exist, several of which can infect people. By far the most common is Legionella pneumophila serogroup 1. The bacteria are ubiquitous and usually harmless in the environment, but they easily can grow in warm, stagnant water. In certain circumstances, especially in institutions housing the elderly or in those with chronic illness, Legionella can multiply and cause pneumonia when people aspirate tiny particles while drinking water or showering.
Since 2001,
SPECIAL CONCERNS FOR SENIOR LIVING
The increase in cases of Legionnaires' disease is of particular concern for owners and managers of LTC facilities. Although anyone can become infected under certain circumstances, Legionnaires' disease principally affects those who are susceptible due to age, illness or compromised immune systems.
Outbreaks usually are followed by lengthy, cosdy litigation. The aforementioned
The need to take action likely is soon to be a part of building codes. In mid- May, ASHRAE (formerly the
Central to the process that may be required by the standard will be assembling a team to be responsible and accountable for building water system safety. This team will conduct a complete survey of potential problems in the water system, such as dead legs where water has sat for a long period of time. If significant risk factors exist, then the team will need to prepare a plan that identifies and establishes control measures at critical points, verifies the control measures are implemented within specific performance limits and validates that the plan is effective in preventing Legionnaires' disease.
The CDC doesn't yet recommend routine environmental cultures for hospitals and nursing homes. In contrast, the
The good news is that compliance with ASHRAE Standard 188P, once it is finalized, will help protect facilities against negligence claims in Legionella-related lawsuits.
Another concern is that an outbreak of Legionnaires' disease also can lead to media scrutiny, unsubstantiated rumors and even panic, causing widespread disruption of services. Residents, family members and facility staff members must be educated and reassured. An outbreak brings in public health officials, and the facility is closed to new residents in the interim.
FINDING THE PROBLEM
Legionnaires' disease involves a significant degree of ambiguity, from whether and how to test to what level of Legionella constitutes a clear danger, to the means needed to remediate the situation. The authors of this article are longtime experts in the clinical pathology of this pathogen and have conducted advanced analyses of remediation solutions. Our evidenced-based work reveals that less-costly interventions, carried out under the supervision of infection control staff, are the most efficacious, least disruptive and the most economical to the facility. Particularly following an outbreak, many organizations waste resources on outside consultants with little experience in public health measures when they should rely on infection control staff who are trained to apply evidence-based medical practices for infectious disease outbreaks.
The amount of Legionella in the water may indicate risk, but how to assess the level is one of the many ambiguities. Although a common means is a measure of colonyforming units per milliliter of water in a sample, we and others have demonstrated it to be an inconsistent metric in terms of assessing risk of contracting Legionnaires' disease.
The percentage of distal sites (samples taken at faucets and showerheads) with Legionella correlates with infection risk. Specifically, a prospective study of 20 hospitals found that when Legionella is present in more than 30 percent of distal sites, patients tended to contract Legionnaires' disease. This is not an absolute indicator, so we recommend testing a minimum of 10 distal sites (with another site per 100 additional residents) in addition to all hot water tanks. Sample sites where the oldest and sickest nursing home residents are concentrated.
Perform routine cultures for Legionella at least once a year. If 30 percent of cultures come back positive, then preventive measures are needed.
Another area of ambiguity is diagnosing the condition. Legionnaires' disease symptoms are those of pneumonia: fever, cough, productive sputum. Treating this disease as pneumonia, however, is highly problematic. Antibiotics used for common pneumonia are ineffective against Legionnaires' disease, and a fatality can occur in less than two weeks. A few clues may raise suspicion: A fever above 102 degrees F and diarrhea signal possible Legionnaires'.
The diagnostic test most used is the Legionella urinary antigen test. It is reasonably accurate but only detects L. pneumophila rerogroup 1. That still accounts for 80 percent of Legionella infections, however.
FIXING THE PROBLEM
If Legionella is found in the water supply and residents have contracted Legionnaires' disease, disinfection of the drinking water is obviously needed. If Legionella is found in enough sites before a resident becomes ill, however, we recommend an innovative approach using intermittent disinfection with intensive monitoring. This approach is inexpensive, and long-term evaluation suggests greater efficacy. (As of this writing, the only provider of this technology is LiquiTech.)
Disinfection modalities can be categorized as either focal or systemic. Focal disinfection refers to disinfection directed at only a portion of a water system, usually the point of entry from the municipal water main or point of use, such as a faucet. Systemic disinfection refers to disinfection directed at the entire water system by providing a disinfectant residual throughout the water system, especially the distal sites.
Point-of-use disposable filters are a focal method to control Legionella in restricted areas in which bedridden residents are congregated. These filters can be applied to a faucet or showerhead quickly and can supplement long-term disinfection options. A focal approach might be applied if the distal site positivity is low and cases have not occurred. Facilities should ensure that the filters they use have been validated by reputable third parties.
A disinfection system installed in the water supply might be applied in facilities experiencing many cases and where the distal site positivity for Legionella is high. Two systemic disinfection methods have proven efficacious against Legionella in laboratory studies and in hospital water supplies: copper-silver ionization and chlorine dioxide.
Numerous investigators worldwide have documented the efficacy of coppersilver ionization in eradicating Legionella from hospital water distribution systems. In this system, a flow cell chamber containing sacrificial copper/silver electrodes is attached to the water supply. A direct current is applied across these electrodes to stimulate the controlled release of ions, which act to starve bacteria of life-sustaining nutrients.
The authors' major 2011 review of all of the existing modalities for remediation of Legionella, published in Infection Control and Hospital Epidemiology, found that copper-silver ionization appears to be the best available technology today for controlling Legionella colonization in hospital water systems when both ion levels and Legionella cultures are monitored.
If a systemic disinfection system is installed because of occurrence of resident cases, then copper-silver ionization may be the preferred approach given its established track record, especially if the news media have reported the outbreak
Chlorine dioxide, a synthetic gas, was first used for Legionella control in
Maintaining a sufficient residual concentration of chlorine dioxide in the hot water system is challenging. Elevated temperature hastens the conversion of chlorine dioxide to chlorite, which may lead to deleterious health issues. An effective residual of the gas must be maintained throughout an extensive water distribution system.
The decay of chlorine dioxide depends on the water temperature and the distance from generation site to the distribution system. Given its rapid decay in hot water, a higher concentration of chlorine dioxide must be injected at the source to reach an effective concentration at the distal site. Thus, the efficacy of chlorine dioxide may be limited to only cold water supplies, not hot water recirculating lines. The advantage of chlorine dioxide is its lower cost compared to copper-silver ionization for the same capacity.
Conversely, the most prominendy used solutions-hyperchlorination and heating and flushing the water distribution system-have significant drawbacks. The first three hospitals in
INEFFECTIVE (AND EXPENSIVE) CONTROL MEASURES
If a consultant suggests either of the following expensive control measures, management should think again, because the recommendations are not only ineffective but logistically tedious to implement and expensive.
* Cleaning of distal outlets. Faucets and showerheads are disinfected by immersion in chlorine of high concentration or boiling water. Or these outlets are replaced with new ones. This method only eradicates the Legionella at the outlets, a small proportion of the total Legionella in an existing plumbing system. Legionella can reappear within days or weeks because it is still present throughout the plumbing system.
* Removing dead legs (unused sections of water pipes). The concept of a "stagnant" aquatic environment in which Legionella readily propagates is an appealing one. Scientific evidence supporting this concept is lacking, however.
CONCLUSION
In summary, Legionnaires' disease is underdiagnosed in nursing homes. When it is discovered, it may be in the context of an outbreak. If deaths occur, panic during the outbreak and exorbitant costs from litigation can occur.
A major benefit of infection control participation is the avoidance of poor decisionmaking during an outbreak. Inexperienced consultants and healthcare facility managers often make cosdy and useless recommendations to management. Prevention can be low-cost and effective. We now are applying a new approach for nursing homes and other LTC facilities that should be more effective, easier to operate and must less expensive than installing a permanent disinfection system.
The impending ASHRAE 188P standard and growing awareness among regulatory bodies may be the tipping point for LTC providers to take immediate steps to learn their risk exposure and act to prevent outbreaks in the name of resident safety, m.
BY YUSEN E. UN, PhD, MBA; AND VICTOR L. YU, MD
Copyright: | (c) 2014 Medquest Communications Inc. |
Wordcount: | 2286 |
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