• Notes from the 8th International Conference on Legionella

    November 03, 2013

    One of the major highlights of the year was SPL's presence at the Eighth International Conference on Legionella in Australia. Dr. Janet Stout was honored to speak and our doctoral student, Julianne Baron, presented posters on SPL's monochloramine study and DNA sequencing. Here are a few highlights from Dr. Stout about the latest research on Legionnaires' disease.

    Clinical presentation of Legionnaires' disease

    More is being learned about the clinical presentation of Legionnaires' disease. Dr. Paul Edelstein, University of Pennsylvania, who spoke on this topic noted:

    • Patients often suffer from post-traumatic stress disorder (PTSD) symptoms after recovery from pneumonia caused by Legionella.
    • Risk of death highest for community-acquired infection in immunocompromised followed by healthcare-acquired infections.

    Increased Outbreaks

    Another notable topic was the increasing number of outbreaks of Legionnaires' disease over the past several years. Jacque Corbeil, Laval University, Canada, reported on the outbreak in Quebec in which 182 cases identified with 13 fatalities:  

    •     24% of the 160 cooling towers tested were positive
    •     Multiple strains of L. pneumophila identified, including six different sequence types
    •     Disease causing strain was isolated from a small cooling tower in downtown Quebec

    Stagnation and Copper Levels

    A Canadian study assessed hot water from 50 water taps in two hospitals for indicators of risk for Legionella amplification. Dr. Michele Prévost, University of Montreal, Canada,reported no increase with stagnation. This was likely due to increased copper levels, which are inhibitory.

  • The Relationship between HPC, ATP, and Legionella in Building and Cooling Tower Water Samples

    November 02, 2013

    Tests that assess microbiological activity are often used by water treatment professionals who are looking for an efficient method to predict the presence of Legionella. Because standard Legionella culture takes at least three days for a preliminary result, many use tests such as adenosine triphosphate (ATP) and Heterotrophic Plate Count (HPC) as a substitute for culture.
     
    ATP is a simple process that can be completed in less than and hour and is an alternative method of microbial population enumeration. Microbial culture methods like HPC provide effective quantification of planktonic microbial populations in water samples. But data comparing each of these methods in terms of accuracy for analysis of Legionella in potable and utility water samples are scarce.

    So we asked the questions: Can ATP or HPC be used as a predictor for Legionella in potable and utility water? We also looked for Legionella to see what if any correlation existed.

    Our purpose of study, in collaboration with the University of Pittsburgh, was to determine:

    1. Sensitivity and specificity of ATP results and correlation with HPC measurements.
    2. Correlation between ATP and HPC measurements and the presence of Legionella in both cooling and drinking water samples.

  • APIC 2013: Impact of Time on Viability and Variability on Legionella Poster Presentation

    October 31, 2013

    SPL studied the effect on holding time and Legionella test results and presented findings in June at the Association for Professionals in Infection Control and Epidemiology (APIC) national conference.

    Testing for Legionella in Healthcare Facilities: Evaluation of the Reproducibility of Legionella Test Results and the Impact of Time on Viability and Variability showed no significant increase or decrease in Legionella viability when cultured within 48 hours, the recommended time between collection and processing.  

  • Eighth International Conference on Legionella Poster Presentations

    October 31, 2013

    Eighth International Conference on Legionella  

    SPL presented two posters on monochloramine in October at the Eighth International Conference on Legionella in Australia.

    • Monochloramine Disinfection of a Hospital Water System for Preventing Hospital-Acquired Legionnaires' Disease: Lessons Learned from a 1.5 Year Study presented more data of the first US field study of a monochloramine generating system in a hospital hot water system. The conclusions show monochloramine to be a promising disinfectant for Legionella.
       
    • Use of Pyrosequencing to Determine the Effects of Monochloramine Treatment on Legionella and Associated Bacterial Populations in a Hospital Hot Water System is the first US study to assess changes in Legionella and microbial flora due to chloramination in a hospital's hot water system using next generation sequencing. This study shows a strong reduction in Legionella presence and a lack of many issues with chloramination found in municipal water supplies. 
  • SPL study disproves claims of variability and viability in Legionella testing

    August 22, 2013

    SPL study disproves claims of variability and viability in Legionella testing

    CLAIM: Major changes occur in Legionella between collection and testing.
    STUDY: In building water samples, we found no significant change in Legionella count between sample collection up to 48 hours after collection.


    CLAIM: Legionella counts vary from site to site.
    STUDY: No significant difference in Legionella concentrations among 12 outlets over 13 sampling dates.


    CLAIM: Percent positivity not dependable tool.
    STUDY: Extent of colonization (percentage of outlets positive) was stable over the study period. This shows reliability for environmental assessment.


    CONCLUSION
    Legionella is stable over time. Samples should be received within 48 hours. Rely on Legionella culture, the gold standard, for Legionella testing (ISO 117231).

  • Special Pathogens Laboratory Director to Speak at International Conference on Legionella in Melbourne

    August 19, 2013

    Special Pathogens Laboratory Director Janet E. Stout, PhD, has been invited to speak at the 8th International Conference on Legionella in Melbourne, Australia.

    Stout, who is also a research associate professor at the University of Pittsburgh Swanson School of Engineering in the Department of Civil and Environmental Engineering, will be speaking on the theme of prevention during the Legionella Control Measures in Hospitals session.

    The conference, held in October, will provide an opportunity for scientists and professionals from across the globe to share information on Legionella, the waterborne bacteria that cause Legionnaires’ disease. Topics to be discussed at scientific symposia include: global trends in Legionnaires’ disease, infection, microbiology, control measures in hospitals, and diagnostics and detection.

    A clinical and environmental microbiologist who has been researching Legionnaires’ disease for more than 30 years, Stout is the author and co-author of numerous research articles and book chapters, including Legionella chapters in the Manual of Clinical Microbiology (American Society for Microbiology) and Hospital Epidemiology and Infection Control. Her expertise includes: Legionella detection, disinfection, remediation and control strategies for the prevention of Legionnaires’ disease. 

    This will be the third time Stout has been honored to speak at the International Conference on Legionella. Her previous lectures occurred in 2009 (Paris) and 2005 (Chicago).

  • Four SCI Somerset inmates test positive for Legionnaires' disease

    July 30, 2013

    A state prison in Somerset County is trying to figure out the source of a Legionnaires' outbreak there that sickened four inmates and how to eradicate the potentially deadly bacteria.

    "We are taking this situation very seriously," state Corrections Secretary John Wetzel said Monday announcing the outbreak. "While the public is not in any danger, we believe in being proactive. Our priority is to prevent further cases."

    The State Correctional Institution Somerset discovered its first case on July 15 only after one of the inmates got so sick that he needed treatment outside the prison, which has an in-house physician, and was tested at Somerset Hospital.

    "That's how we discovered it," said Al Joseph, the prison's spokesman. "One of them was outside for treatment and was tested for Legionella and it was positive."

    The prison, which holds about 2,300 inmates and has 600 employees, began looking for cases after that. A second inmate was diagnosed July 21, and two more on July 24. All four are in recovery inside the prison.

    After the third and fourth cases, the state prison decided to hire Special Pathogens Laboratory, a Legionella consultant company in Pittsburgh run by internationally known experts Victor Yu and Janet Stout.

    Dr. Yu said he and his colleague are reviewing data from water tests to try to determine the most likely source of the disease, which is spread through water, often when people drink water contaminated with Legionella bacteria.

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  • Managing Risk During Construction

    July 20, 2013

    The risk of infection from Legionella and other waterborne pathogens to building occupants can increase during construction and maintenance of water systems in complex buildings, especially in healthcare facilities. There are steps you can take during the planning, design, construction, and commissioning phases of construction and renovation work to minimize the risk.

    Recommendations to minimize risk of Legionella and other waterborne pathogens during construction:

    Phase 1. Planning

    Complete the Facilities Guidelines Institute's Infection Control Risk Assessment (ICRA) to identify the type of construction or renovations and what building occupants will be impacted. Use a matrix approach to establish the class of precautions to be followed during design, construction, and commissioning; be sure it provides consideration for water system construction activities.

    Phase 2. Design 

    Regardless of the scope, consider the impact construction could have on water quality and how it could affect the growth of Legionella and waterborne pathogens in your water system.

    Phase 3. Construction

    Provide oversight during construction to ensure that the work is being completed per the design and that ICRA recommendations are implemented to minimize the spread of Legionella and waterborne pathogens.

    Phase 4. Commissioning

    For minor plumbing work, commissioning can include checking for leaks and flushing a fixture; however for widespread water service interruptions or new work, commissioning should include disinfection, flow and temperature checks, sampling and culture for waterborne pathogens, including Legionella, and continual movement of water until the building is occupied.

  • Seven Misconceptions about Legionella

    July 03, 2013

    1. No safe level of Legionella in your building water system.
      The CDC is quoted in news reports as saying "there are no safe levels of Legionella." This view reflects a public health response to a crisis situation in which the tolerance for risk is zero. However, from a performance perspective, this is an unrealistic proposition.

      Furthermore, CFU/ml hasn't been shown to be predictive of risk for Legionnaires' disease; rather studies have shown the extent of colonization (proportion of sites positive) to be a better predictor of increased risk, particularly when Legionella pneumophila, serogroup 1, is present and distal site positivity exceeds 30%.
      Stout J. Infect Control Hosp Epidemiol. 2007 Jul;28(7):818-24.

      So how much Legionella is too much?
      Building water systems are complex and home to millions of microbes—Legionella just one of many species. Both the FDA and EPA provide action levels for a variety of contaminants because getting and staying at zero, while ideal, is nearly impossible. They establish maximum contaminant goals (MCG). For a more realistic approach, establish targets for Legionella: action levels, minimum levels, and goals.

    2.  Heterotrophic Plate Count is predictive of Legionella.
      Many people believe that knowing your total bacteria count provides an accurate snapshot of what's in your water including Legionella. However, studies show there is no correlation between total bacteria count and Legionella. Legionella requires specialized culture media and will not grow on HPC media. 
      Lin Yu, JAWWA, 1998:90, 112-121.
       
    3. Only those with defined risk factors (elderly, smokers, immunocompromised) get Legionnaires' disease.

      Approxiamately, 25 percent of those who contract Legionnaires' disease are not in the risk groups.
      Squier, AJIC, 2005; 33:360-7
       
    4. Look first to the cooling tower.
      Some people still mistakenly think air-conditioning systems and cooling towers are responsible for most cases of Legionnaires' disease. However, current data suggest that cooling towers and evaporative condensers, while still potential sources for Legionnaires' disease, may be overemphasized as a means of Legionella transmission. Domestic (potable water) plumbing systems are a notable source as well. Such systems have been commonly linked to occurrences and transmissions of Legionnaires' disease in large buildings and/or complexes.   
      Yu, Int. J. Hyg. Envrion. Health 211(2008) 229-234
       
    5. Legionella is everywhere (ubiquitous).
      Many say there is no point in testing for Legionella because you will always find it. However, a range of studies show that Legionella is not everywhere. In fact, Legionella colonizes the water in 12 to 70 percent of buildings. So, wouldn't you want to know if your facility was one of the buildings where Legionella was not found?
      Lin YE. Infect Control Hosp Epidemiol. 2011 32(2):166-173

    6. Maintenance of your water system is the key to prevention.
      A widespread misconception is that good engineering practices and preventive maintenance of the water distribution system will prevent Legionella colonization. However, hospitals and commercial buildings that followed a preventative maintenance program that included cleaning or flushing hot water storage tanks on a weekly to annual basis were as likely to be contaminated with Legionella as those that did not.
      Stout J, ASHRAE, 2007 
       
    7. Water stagnation causes Legionella to multiply.
      Our 2006 study, using a model plumbing system, to determine the effect of flow regimes on the presence of Legionella within microbial biofilms failed to show that stagnation promoted growth of Legionella. Furthermore, removal of dead leg pipes did not decrease Legionella colonization.
      Liu Z. J Appl Microbiol. 2006;101:437-42.
  • Legionnaires' Disease in the VA Hospital System: WESA Interview

    June 11, 2013

    In a series of articles in the Pittsburgh Tribune-Review, reporter Adam Smeltz has investigated on the prevalence of the Legionella bacteria, which causes Legionnaire's disease, in Pittsburgh's VA hospital in Oakland.  His findings indicate that there may have been reason to fear an outbreak in the hospital prior to the one that occurred in 2011.

    We'll be joined in studio by Smeltz as well as Dr. Janet Stout, a Legionella expert and director of Special Pathogens Laboratory, as well as a former employee of the Pittsburgh VA hospital system