title: [Genotypic variability and persistence of Legionella pulsed-field gel electrophoresis patterns in 16 cooling towers in Shanghai, China].
abstract: OBJECTIVE
  To investigate the genotypic characteristics and persistence of Legionella pulsed-field gel electrophoresis (PFGE) patterns in 16 air-conditioner cooling towers in six different public sites of Shanghai.
  
  
  METHODS
  From May to October, continuous sampling was operated once per month in 2007. Legionella strains isolated from the 16 cooling towers were confirmed by serological and latex agglutination. PFGE was applied for the fingerprinting of the isolates, while the cluster results of PFGE were analyzed by BioNumerics software.
  
  
  RESULTS
  131 strains of Legionella were isolated, including L. pneumophila, L. bozemanae, L. micdadei and L. anisa. 52 distinguishable PFGE patterns were differentiated among the 16 cooling towers, with 37 patterns were owned by just one cooling tower, which was not shared with other cooling towers, while 15 patterns were shared by more than 2 cooling towers. All the cooling towers had ≥ 2 PFGE patterns, while in 13 cooling towers the same PFGE patterns were recovered during the six months. From June to October of 2007, 18 strains of Legionella belonging to the PFGE pattern of LPAs.SH0078 were isolated continuously from 6 cooling towers.
  
  
  CONCLUSIONS
  This study demonstrated great genotypic diversity and complexity of Legionella in cooling towers. Persistence of the PFGE patterns was observed in 81.25% of the cooling towers. The PFGE pattern of LPAs. SH0078 was distributed widely, suggesting it might be the dominate strain in Shanghai.
authors.affiliation: Shanghai Municipal Center for Disease Control and Prevention, Shanghai 200336, China.
authors.forename: Ming-liang
authors.initials: ML
authors.lastname: Chen
authors.forename: Gang-yi
authors.initials: GY
authors.lastname: Wang
authors.forename: Min
authors.initials: M
authors.lastname: Chen
authors.forename: Hai-jian
authors.initials: HJ
authors.lastname: Zhou
authors.forename: Zhu-jun
authors.initials: ZJ
authors.lastname: Shao
authors.forename: Xi
authors.initials: X
authors.lastname: Zhang
authors.forename: Fan
authors.initials: F
authors.lastname: Wu
mesh_terms: D000389:Air Conditioning; D002681:China; D004269:DNA, Bacterial / Q000235:genetics; D016521:Electrophoresis, Gel, Pulsed-Field; D005838:Genotype; D007875:Legionella / Q000235:genetics* / Q000302:isolation & purification; D014871:Water Microbiology; D014881:Water Supply
chemical_list: D004269:DNA, Bacterial