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557 Environmental Monitoring of Legionella Colonization in Hospital Water Distribution Systems in Taiwan

Sunday, April 3, 2011
Trinity Ballroom (Hilton Anatole)
Yusen Eason Lin, PhD, MBA , National Kaohsiung Normal University, Kaohsiung, Taiwan
Yi-chun Lin, MS , National Kaohsiung Normal University, Kaohsiung, Taiwan
Hsiu-yun Shih, MS , National Kaohsiung Normal University, Kaohsiung, Taiwan
Yao-shen Chen, MD , Infectious Diseases Section, Kaohsiung Veterans General Hospital, Kaohsiung, Taiwan
Fang-Yee Chang, MD, PhD , Center for Disease Control, Taiwan, Taipei, Taiwan
Thomas C. Yang, PhD , National Kaohsiung Normal University, Kaohsiung, Taiwan
Background: Legionnaires’ disease is a major cause of hospital and community acquired pneumonia. Unlike other causes of pneumonia, Legionnaires’ disease is acquired from the environment, and therefore amenable to prevention. 

Objective: To investigate the the presence of Legionella pneumophila and its colonization rate in hospital water systems in Taiwan.

Methods: Seventeen hospitals (Hospitals A to Q) throughout Taiwan (8 in northern, 1 in central, 6 in southern, and 2 in eastern Taiwan) were cultured for L. pneumophila. We followed the standardized protocol to perform environmental cultures using (1) swab and water samples; (2) BCYE and DGVP culture media; (3) latex agglutination test (LAX) and direct fluorescent antibody (DFA) technique for L. pneumophila speciation and serotyping. 

Results: 59% (10/17) of hospital water systems are positive for Legionella. For those hospital potable water systems that yielded L. pneumophila serogroups 1, 6, 3 were isolated from 70% (7/10), 50% (5/10), and 40% (4/10) of the hospitals, respectively. The water distribution system of Hospital N had the highest yield (50%, 10/20) of positive distal sites. Four hospitals (C, K, M, N) have distal site positivity greater than 30%. A strong correlation was found between the Legionella culture positivity rate and the geographical location. All six hospitals in southern Taiwan were colonized by L. pneumophila, while only 12.5% (1/8) of hospitals in northern Taiwan were colonized by Legionella. It is noteworthy that the two hospitals (P, Q) in eastern Taiwan that are previously negative for Legionella by Yu et al. are both positive in this surveillance; however, the positivity rate is extremely low (5% in Hospital P and 8.3% in Hospital Q, respectively). 

Conclusions: This study allow health official and healthcare professionals for the development of water safety plan to better protect patients and residents of Taiwan in an attempt to prevent Legionnaires’ diseases.