June 23, 2016
Nontuberculous mycobacteria (NTM) infections and contamination associated with heater-cooler devices, especially during cardiac surgery are a growing concern. According to the FDA’s Medical Device Review (MDR) database, US hospitals across 10 states account for 34% of infections or device contamination worldwide.
NTM is a naturally occurring group of bacteria found in soil and water, including chlorinated water. Aerosolization from heater-cooler devices has been shown to contaminate the sterile operative field resulting in patient infections.
In June 2015, LivaNova (formerly Sorin), the manufacturer of HT 3 heater-cooler devices, issued a field safety notice with disinfection protocols. Recommendations included implementing microbiological monitoring to verify effectiveness. Monthly tests include: heterotrophic plate count, coliform bacteria, Pseudomonas aeruginosa, and nontuberculous mycobacteria.
Special Pathogens Laboratory (SPL) isolated Mycobacterium chimaera from 25 of 43 heater-cooler devices. Reports found this same species at LivaNova’s production facility in Germany. Diagnosing M.chimaera infections is complicated as symptoms may not appear until one to three years after surgery. However, SPL’s early data shows a decrease in contamination after clients disinfected their devices.
Share your experience about disinfecting your heater-cooler system for our study.
August 07, 2015
New York City is in the throes of a major outbreak of Legionnaires’ disease. A hundred people have been stricken and at least ten are dead. The origin is thought to be building cooling towers in which bacteria are growing.
Although they receive little attention, outbreaks of Legionnaire’s disease, which is caused by a bacterium called Legionella, are not uncommon, and they’re increasing. The number of cases in New York City has tripled during the last decade, increasing from 73 in 2004 to 225 in 2014. Nationally, reported cases more than tripled between 2001 and 2012. The fatality rate is 5 to 30 percent.
The country is ill-prepared to stem the tide of Legionnaire’s outbreaks, in large part because of the flawed policies of the federal Centers for Disease Control and Prevention (CDC).
Legionella lurks at low levels in natural fresh water sources (such as rivers, lakes and streams) in virtually every part the world, most often with little impact on humans. It becomes hazardous when it survives municipal water treatments and subsequently contaminates and grows in man-made building water systems such as hot tubs, decorative fountains, shower heads and cooling towers. Left undetected in these sites, it can multiply to high concentrations. People become sickened after inhaling contaminated aerosol droplets generated from these sources. Unlike most other pneumonias caused by microorganisms, this disease is not transmitted person-to-person; it is purely of environmental origin.
The only way to determine whether a water source is a high-risk Legionella-contaminated system is to take samples of the water to see whether the bacteria grow from them, in a simple and inexpensive culture test in a laboratory. But instead of mandating regular monitoring of possible sources, the CDC endorses a “disease surveillance” strategy–a reactive approach that relies on screening for bacteria after cases are detected, at which time a response is quickly undertaken to prevent further infections. Although this strategy works well for person-to-person transmissible diseases where the source of the disease is another infected individual, it is not well suited to situations in which the source of disease is in the environment.
Former Assistant U.S. Surgeon General Dr. J. Donald Millar, who used the disease surveillance approach as the head of CDC’s hugely successful Smallpox Eradication Program, has long been critical of CDC’s approach to Legionnaire’s disease. In1997 he warned that disease surveillance was being misapplied to the prevention of Legionnaires’ disease because it is not transmitted from person to person but is contracted solely by exposure to bacteria-contaminated aqueous sources. For such diseases of environmental origin, proactive environmental surveillance, rather than reactive disease surveillance, is the appropriate prevention strategy.
And yet CDC officials remain intransigent, discouraging environmental testing until an outbreak occurs, at which point they demand testing to demonstrate that all evidence of Legionella is absent for up to a year
after the outbreak. Inexplicably, CDC’s current recommendation is still that “an epidemiological association with a probable source should be established before intervention methods, such as disinfection, are undertaken” [emphasis added].
This contradiction–environmental surveillance not indicated before an outbreak, but required afterwards–in effect uses people as “canaries in the coal mine” to detect high-risk water sources.
March 02, 2015
It's quite common to find Legionella species other than Legionella pneumophila in cooling towers and water distribution systems. To date, fifty-eight Legionella species have been described in published articles. Of these approximately 25 are linked to disease.
Legionella pneumophila serogroup 1 is the most virulent strain causing the majority of infections. The remaining non-pneumophila species (found in water and soil) are considered nonpathogenic until shown to cause disease. Of the CDC reported cases less than 5% are attributed to these species. Since risk for infection is rare, adjusting your response to an adequate threat level is appropriate.
For example, there are Legionella species whose colonies exhibit blue-white fluorescence under long-wave UV light and some exhibit red fluorescence. These "blue-white" Legionella species include: L. anisa, L. dumoffii, L. gormanii, L. cherri, L. parisiensis and L. bozemanii. The red fluoresceing species include: L. erythra and L. rubrilucens. Such non-pneumophila species are commonly found in the environment, but rarely cause infection and when they do it is almost exclusively in very immunocompromised individuals.
In SPL's study, Role of Environmental Surveillance in Determining the Risk of Hospital-Acquired Legionellosis: A National Surveillance Study With Clinical Correlations (ICHE July 2007, Vol 28 No. 7. P 818 - 824) investigators found no infection from species like L. anisa even though it was present in the water systems.
Take the analogy of bacteria on skin. We know our skin is covered with many bacteria including Staphylococcus aureus, but we only get infections under extreme conditions. Most staph on our skin is inherently not pathogenic but if a patient is immuno-compromised or has a procedure that helps staph gain entry into the body, infection can occur. This is sometimes referred to as an "opportunistic infection." Like staph other Legionella species are common in the environment but won't cause illness under normal circumstances.
To say that all Legionella species have the "potential" to cause illness is mere speculation. More than 30 years of research shows few or no reported illnesses from more than half of the known Legionella species. So it's safe to assume the risk of disease is so low as to not to be actionable.
When assessing risk rely on science rather than speculating about unknowns. When other or new Legionella species are found to contribute significantly to the disease threat, then risk assessments could be adjusted. For now it's appropriate to adjust your response to an adequate threat level as seen is the recent VA Directive that non-pneumophila species only require disinfection in limited circumstances.
February 14, 2015
It's common to find other Legionella species in your water. As previously mentioned, the Legionella family is a big family with 58 species that exist in soil and water. When you find other Legionella species does that mean Legionella pneumophila serogroup 1 is also present?
An often cited 2006 French study attempts to make the case that after eradicating L. anisa by thermal shock treatment Legionella pneumophila serogroup 1 (LP1) appeared and that L. anisa had "masked" LP1. The authors assert that system-wide disinfection is required to reveal LP1 and that the presence of the non-pneumophila species was a predictor of the presence of the more dangerous Legionella pneumophila serogroup 1.
No other studies support their claim that finding one Legionella species predicts the presence or absence of LP1. While it's true that multiple serogroups and even species can colonize a water system, we aren't aware of any study that has statistically correlated the presence of a non-pneumophila species as predictive of the presence of LP1.
The ability of a laboratory to detect some non-pneumophila Legionella species is dependent upon the methods and culture media used by the laboratory. For example, some species won't grow in the presence of glycine--a common additive in Legionella selective media used to isolate Legionella from the environment.
Even so, based on this claim French researchers concluded that action should be taken to "eradicate all Legionella contamination."
In contrast, all studies show that LP1 is the primary cause for disease. While non-pneumophila species have caused illness on rare occasions, to conduct a system-wide disinfection when only non-pneumophila species, such as L. anisa, are isolated is a time-consuming and costly proposition backed by very little evidence to support such an action.
To better illustrate, take a recent example. During an investigation of a facility for a suspected case of Legionnaires' disease due to L. pneumophila serogroup 1, the testing of the facility only revealed the presence of Legionella feelei. No link could be made between the illness caused by L. pneumophila serogroup 1 and the facility. Despite this, the health department, citing CDC guidance, insisted on restricting admissions, restricting showering, use of bottled water and multiple shock chlorine treatments of the water system until all cultures were zero. The impact of these measures on the patients, staff and operation of this facility caused hardship and were extremely expensive.
In our opinion, all of these precautions were unnecessary and could have been lifted when environmental testing failed to show the presence of L. pneumophila serogroup 1.
January 28, 2015
Risk Assessment and Prediction for Healthcare-Associated Legionnaires’ Disease: Percent Distal Site Positivity as a Cut-Point
To date there is no definitive indicator for risk of disease regarding levels of Legionella. In 1983, SPL researchers offered a cut point based on the proportion of outlets (faucets and showers) positive for L. pneumophila. Clinical experience supported this approach. If 30% or greater of outlets was positive for Legionella, environmental and clinical surveillance must be done concurrently; and depending on the extent of colonization consider disinfection. The Allegheny County Health Department was the first to adopt the cut point that public agencies and hospitals now use worldwide.
However, an article published in American Journal of Infection Control (AJIC) challenged this approach. SPL’s editorial commentary, Risk Assessment and Prediction for Healthcare-Associated Legionnaires’ Disease: Percent Distal Site Positivity as a Cut-Point, examines the flaws of that study. That is, researchers applied the 30% criteria to studies not designed to assess this endpoint and therefore the data presented doesn’t prove or disprove the efficacy of the cutpoint.
Commentary Abstract: Legionella has been reported as the single most commonly reported pathogen associated with disease outbreaks from drinking water. Two strategies have been proposed for risk assessment. The first is the strategy advocated by the Centers for Disease Control and Prevention (CDC) to search assiduously for Legionnaires' disease in all cases of hospital-acquired pneumonia. However, the diagnosis is commonly missed, even if the Infectious Diseases Society of America and American Thoracic Society guidelines are followed.
July 22, 2014
The agency’s reactive approach to Legionnaires’ disease causes thousands of preventable infections every year.
... Legionella, the cause of Legionnaires’ disease, was originally identified after an outbreak at an American Legion Convention in a Philadelphia hotel in 1976 that killed 34 and sickened 221. The bacterium lurks at low levels in natural fresh water sources (such as rivers, lakes and streams) in virtually every part the world, most often with little impact on humans. It becomes hazardous when it survives municipal water treatments and subsequently contaminates and grows in man-made building water systems such as hot tubs, decorative fountains, shower heads and cooling towers. Left undetected in these locations, it can multiply to high concentrations. People become sickened after inhaling contaminated aerosol droplets generated from these sources.
Unlike most other pneumonias caused by microorganisms, this disease is not transmitted person-to-person; it is purely of environmental origin.
The only way to determine whether a water source is a high-risk Legionella-contaminated system is to take samples of the water to see whether the bacteria grow in a simple and inexpensive culture test in a laboratory.
Although they receive little attention, outbreaks are not uncommon. By far, however, most cases of Legionnaires’ disease are individual sporadic cases that are not known to be associated with larger outbreak clusters, although this may be due to the fact that most sporadic cases are never thoroughly investigated. (Legionnaires’ disease symptoms are similar to other pneumonias and can only be diagnosed by specific laboratory tests.) Estimates of the number of cases annually in the United States range from 8,000 to more than 25,000.
An obvious question is what federal health officials are doing to protect Americans from this disease. The answer is both complicated and puzzling. The approach of the CDC’s National Center for Immunization and Respiratory Diseases (NCIRD), which has the responsibility for Legionnaires’ disease prevention, is flawed. Perhaps that is not surprising, given that prevention appears not to be NDIRD’s strong suit; its officials also recommended eliminating the fourth booster dose for the childhood pneumococcal vaccine although that would reduce the efficacy of vaccination and result in the death of children (the subject of a previous Forbes article).
The CDC’s recommendations for preventing Legionnaires’ disease have been predominantly focused on what might termed a disease surveillance strategy–a reactive process that relies on screening for disease after cases are detected, at which time a response is quickly undertaken to prevent further infections. Although this strategy works well for person-to-person transmissible diseases where the source of the disease is another infected individual, it is not well suited to situations in which the source of disease is in the environment...