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Further laboratory results available today (April 14) confirmed the preliminary test results reported on April 11 concerning water samples taken in Queen Mary Hospital (QMH) in the wake of a Legionnaires' Disease (LD) case involving an 81-year-old woman.
A spokesman for the Centre for Health Protection (CHP) of the Department of Health said that laboratory results for the first round of water samples collected from water outlets at Intensive Care Unit (C2 ward) and C4 ward confirmed the level of Legionella species to range from 0.1 to 12 cfu/ml. No Legionella pneumophila (Group One) was found. LD is usually caused by Legionella pneumophila (Group One).
No Legionella bacteria was detected in the water sample collected at the water tank supplying these wards, suggesting that the water source is free from contamination.
Water samples collected at the case's residence were all negative for Legionella bacteria.
According to international standards, immediate control measures including disinfection should be taken when the levels for Legionella bacteria in hot and cold water systems exceed 0.1 -1 cfu/ml.
QMH has already suspended the contaminated water supply and stepped up appropriate infection control measures.
Legionella bacteria are found in various environmental settings and grow well in warm water (25 to 40 degrees Celsius). They can be found in aqueous environments such as water tanks, cooling towers, whirlpool and spas, water fountains and apparatus that support breathing. Proper design, operation and maintenance of man-made water systems could prevent LD.
For more information about proper design, operation and maintenance of man-made water systems, please visit the EMSD's website (www.emsd.gov.hk) for the Code of Practice issued by the Prevention of LD Committee.
Investigation continues.
Ends/Thursday, April 14, 2011
Issued at HKT 20:03
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