Prevalence and Molecular Characteristics of Waterborne Pathogen Legionella in Industrial Cooling Tower Environments

International Journal of Environmental Research and Public Health

Lijie Li²  Tian Qin¹  Yun Li⁵  Haijian Zhou¹  Hongmei Song²  Hongyu Ren¹  Liping Li²  Yongguang Li³  Dong Zhao²  Nicholas Frederick Gray⁴ 

[1] State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, No. 155, Changbai Road, Changping, Beijing 102206, China; E-Mails:;Shijiazhuang Center for Disease Control and Prevention, No.3, Likang Street, Shijiazhuang 050011, China; E-Mails:;Shijiazhuang Jiyuan Environmental Protection Technology Co.Ltd, Shijiazhuang 050035, China; E-Mail:Shijiazhuang Center for Disease Control and Prevention, No.3, Likang Street, Shijiazhuang 050011, China;;Hebei International Travel Health-Care Center, No.409-1, Hongqi Stree, Shijiazhuang 050000, China; E-Mail:

关键词: aquatic bacteria;    Legionella;    Legionella monitoring;    cooling tower water;    molecular characteristics;    water pollution;   

DOI  :  10.3390/ijerph121012605

来源: mdpi

【 摘 要 】

Cooling towers are a source of Legionnaires’ disease. It is important from a public health perspective to survey industrial cooling towers for the presence of Legionella. Prospective surveillance of the extent of Legionella pollution was conducted at factories in Shijiazhuang, China between March 2011 and September 2012. Overall, 35.7% of 255 industrial cooling tower water samples showed Legionella-positive, and their concentrations ranged from 100 Colony-Forming Units (CFU)/liter to 88,000 CFU/liter, with an average concentration of 9100 CFU/liter. A total of 121 isolates were obtained. All isolates were L. pneumophila, and the isolated serogroups included serogroups 1 (68 isolates, 56.2%), 6 (25, 20.7%), 5 (12, 9.9%), 8 (8, 6.6%), 3 (6, 5.0%) and 9 (2, 1.6%). All 121 isolates were analyzed by pulsed-field gel electrophoresis (PFGE) and 64 different patterns were obtained. All 121 isolates were analyzed sequence-based typing (SBT), a full 7-allele profile was obtained from 117 isolates. One hundred and seventeen isolates were divided into 49 sequence types. Two virulence genes, lvh and rtxA, are analyzed by polymerase chain reaction (PCR). 92.6% (112/121) and 98.3% (119/121) isolates carried lvh and rtxA respectively and 90.9% (110/121) of tested isolates carried both genes. Our results demonstrated high prevalence and genetic polymorphism of L. pneumophila in industrial cooling tower environments in Shijiazhang, China, and the SBT and virulence gene PCR results suggested that the isolates were pathogenic. Improved control and prevention strategies are urgently needed.

【 授权许可】

CC BY   
© 2015 by the authors; licensee MDPI, Basel, Switzerland.