title: [Three quantitative methods to continuously monitor Legionella in spring water].
abstract: OBJECTIVE
  To compare the detection effect of Legionella pollution in spring water by three methods, namely traditional plating method, fluorescent quantitation PCR method and ethidium monoazide (EMA) fluorescent quantitation PCR method.
  
  
  METHODS
  Every month (except May), we collected 11 water samples from the 5 selected hot spring pools in one hot spring resort in Beijing in 2011. A total of 121 water samples were collected, and then were detected by the above three methods qualitatively and quantitatively.
  
  
  RESULTS
  In our study, the Legionella pollution rate was separately 74.4% (90/121), 100.0% (121/121) and 100.0% (121/121) by the above three methods. The quantitative value of Legionella in the 121 water samples detected by the three methods were around 0.10-216.00 colony-forming units (CFU)/ml, 1.47-1557.75 gene units (GU)/ml and 0.20-301.69 GU/ml, respectively. The median (25th and 75th percentiles) was 75.30 (32.51-192.10) GU/ml, 36.46 (16.08-91.21) GU/ml and 5.30 (0.00-33.70) CFU/ml, respectively. The difference in the quantitative value of Legionella detected by the three methods showed statistical significance (χ(2) = 187.900, P < 0.01). The quantitative value of Legionella detected by fluorescent quantitation PCR method was the highest, followed by the value Legionella detected by EMA-fluorescent quantitation PCR method and traditional plating method.
  
  
  CONCLUSIONS
  The sensitivity of the PCR methods was higher than traditional plating method, in detecting Legionella pollution in spring water, especially the EMA- fluorescent quantitation PCR method, which was more suitable for detecting Legionella in water.
authors.affiliation: Department of Communicable Disease Control and Prevention, Changping District Center for Disease Control and Prevention, Beijing 102200, China.
authors.forename: Ge-bin
authors.initials: GB
authors.lastname: Yan
authors.forename: Huan-xin
authors.initials: HX
authors.lastname: Wang
authors.forename: Tian
authors.initials: T
authors.lastname: Qin
authors.forename: Hai-jian
authors.initials: HJ
authors.lastname: Zhou
authors.forename: Ma-chao
authors.initials: MC
authors.lastname: Li
authors.forename: Ying
authors.initials: Y
authors.lastname: Xu
authors.forename: Ming-qiang
authors.initials: MQ
authors.lastname: Zhao
authors.forename: Zhu-jun
authors.initials: ZJ
authors.lastname: Shao
authors.forename: Hong-yu
authors.initials: HY
authors.lastname: Ren
mesh_terms: D004784:Environmental Monitoring / Q000379:methods*; D045482:Hot Springs / Q000382:microbiology*; D007875:Legionella / Q000145:classification / Q000302:isolation & purification*; D008828:Microbiological Techniques; D014871:Water Microbiology