Update on investigation into case of Legionnaires' disease
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The case involves a female patient, aged 49, who was admitted to Hong Kong Sanatorium & Hospital (HKSH) from August 12 to September 10. Her respiratory specimen tested positive for Legionella pneumophila serogroup 1 (Lp1) upon laboratory testing.
Water samples and environmental swabs were collected from HKSH to test for legionella in a joint investigation by the CHP and the Electrical and Mechanical Services Department on the possible source of infection and to support the implementation of control measures.
Regarding water samples, three out of 15 tested positive for Lp1, with levels from 0.1 to 0.2 colony-forming units per millilitre (cfu/ml). According to the CHP's risk-based strategy, the total Legionella count of this trio was higher than the action level of water systems in high-risk areas of hospitals, i.e. 0.1 cfu/ml or above. They were collected from the water tap and shower in the toilet of the patient's rooms and the water dispenser of the ward.
"Our laboratory investigations show that the patient's respiratory specimen and the positive water samples were of the same sequence type of Lp1. Investigations at this stage cannot rule out the possibility of a nosocomial infection," a spokesman for the CHP said.
"We have advised HKSH to replace the water outlets concerned and provided health advice against LD to hospital staff and in-patients, including those with weakened immunity, who should use sterile or boiled water for drinking, teeth brushing and mouth rinsing," the spokesman said.
"Medical surveillance in the ward to which the patient was admitted has been enhanced in collaboration with HKSH and no additional cases have been identified thus far. We will maintain close liaison with HKSH to monitor the latest developments. Epidemiological investigations are ongoing," the spokesman added.
As of September 30, a total of 62 LD cases (58 community-acquired, two nosocomial, one institutional and the said case unclassified) had been reported in 2017. In 2016 and 2015, there were 75 and 66 cases respectively.
Ends/Friday, October 6, 2017
Issued at HKT 18:42
Issued at HKT 18:42
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