Legionella E-news, 31 May 2006
Matthew R. Freije, Editor
**IN THIS ISSUE**
1. More Cases at Rochester, N.Y. Hospital
2. Hotel is Suspected in 15 Cases in Spain
3. Monochloramine may Increase Lead Levels in Drinking Water
4. Water Versus Swab Samples from Faucets
5. Legionella Management Plans
1. MORE CASES AT ROCHESTER, N.Y. HOSPITAL
In February, four Legionnaires' cases occurred among patients at a hospital in Rochester, N.Y., one of whom died (see Legionella Enews, February 23, 2006). All patients were given bottled water, showering was restricted, and the water system was chlorinated and considered free of Legionella based on water tests. Despite the hospital’s efforts to disinfect the water, a cancer patient tested positive for Legionnaires' in early May, and died. A sixth patient, admitted on May 13 for an injury, contracted the disease about five days later. Because the fifth patient did not have the same Legionella strain as the first four cases, and water tests have been negative for Legionella since February, hospital officials suspect that the two recent cases may have been acquired prior to admission. Source: Rochester Democrat and Chronicle
2. HOTEL IS SUSPECTED IN 15 CASES IN SPAIN
Fifteen retirees from Spain's Catalonia region were treated for Legionnaires' disease following a stay in a hotel in a southern Spanish town. The retirees, all between 60 and 85 years old, had stayed in the same hotel between March 25 and April 12. Health officials collected water samples from the hotel’s water systems and an ornamental fountain. Local authorities ordered the hotel to shut down as a precaution. Source: Xinhua
3. MONOCHLORAMINE MAY INCREASE LEAD LEVELS IN DRINKING WATER
Real-time corrosion studies conducted by chemist Jay Switzer at the University of Missouri–Rolla show that lead on pipes are more likely to dissolve into drinking water when chloramines are used as a disinfectant. The research is published in the May 15, 2006 issue of Environmental Science & Technology. Chloramines have reportedly been linked to elevated levels of toxic lead in drinking water in Washington, D.C., and Greenville, N.C. The news report is posted at http://pubs.acs.org/subscribe/journals/esthag/40/i10/html/051506news2.html. The reference for the paper is: Switzer JA, Rajasekharan VV, Boonsalee S, Kulp EA, Bohannan EW. "Evidence that monochloramine disinfectant could lead to elevated Pb levels in drinking water." Environ. Sci & Technol. 40, 3384-3387 (2006)
4. WATER VERSUS SWAB SAMPLES FROM FAUCETS, by Matt Freije
If Legionella culture were not so expensive, most investigators would collect both swab and water samples from faucets. But because of budget constraints, usually one or the other is collected in routine (versus outbreak-related) screenings. Several factors should be considered in choosing between water and swab samples. Here are three of them:
a. Quantitation: Test results are interpreted by considering the percentage of positive sites in a given screening, the Legionella concentration per sample (quantitation), and the Legionella strain. Water samples provide more accurate quantitation (e.g., per ml), whereas the amount of substance swabbed will vary from sample to sample. Swab samples provide only a ballpark quantitation and comparison.
b. Reflection of risk: A water sample will give the total picture of what is coming out of the faucet at the time a sample is collected--the legionellae that broke free from biofilm not only at the faucet but also from the piping preceding it--but swab samples will show only the legionellae in the biofilm at the outlet. For the same reason, however, water samples are more time-dependent than swab samples, because only the legionellae that actually break away from biofilm at the time a water sample is taken will end up in the bottle. Thus swab samples may more accurately indicate potential risk.
c. Aerators: If a faucet has an aerator, a water sample is probably the better choice. Removing the aerator and swabbing the interior of the faucet may give a “false negative” because detectable legionellae may be in the biofilm in the aerator, but not in the faucet neck. The investigator could swab the aerator in addition to the faucet, but competing bacteria in the sediment of the aerator may render the sample uninterpretable or negative. -MRF
5. LEGIONELLA MANAGEMENT PLANS
For hospitals: http://hcinfo.com/318info.htm
For nursing Homes and Senior Living Facilities: http://hcinfo.com/319info.htm
For hotels: http://hcinfo.com/320info.htm
The management plans read like an in-house policy manual. Each is available in print (softcover) or on a CD for US$149 plus shipping, or can be downloaded at www.hcinfo.com for $119.
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