title: Usefulness of real-time PCR as a complementary tool to the monitoring of Legionella spp. and Legionella pneumophila by culture in industrial cooling systems.
abstract: OBJECTIVE
  This study was designed to evaluate the usefulness of quantification by real-time PCR as a management tool to monitor concentrations of Legionella spp. and Legionella pneumophila in industrial cooling systems and its ability to anticipate culture trends by the French standard method (AFNOR T90-431).
  
  
  RESULTS
  Quantifications of Legionella bacteria were achieved by both methods on samples from nine cooling systems with different water qualities. Proportion of positive samples for L. pneumophila quantified by PCR was clearly lower in deionized or river waters submitted to a biocide treatment than in raw river waters, while positive samples for Legionella spp. were quantified for almost all the samples. For some samples containing PCR inhibitors, high quantification limits (up to 4·80 × 10(5) GU l(-1) ) did not allow us to quantify L. pneumophila, when they were quantified by culture. Finally, the monitoring of concentrations of L. pneumophila by both methods showed similar trends for 57-100% of the samples.
  
  
  CONCLUSIONS
  These results suggest that, if some methodological steps designed to reduce inhibitory problems and thus decrease the quantification limits, could be developed to quantify Legionella in complex waters, the real-time PCR could be a valuable complementary tool to monitor the evolution of L. pneumophila concentrations.
  
  
  CONCLUSIONS
  This study shows the possibility of using real-time PCR to monitor L. pneumophila proliferations in cooling systems and the importance to adapt nucleic acid extraction and purification protocols to raw waters.
authors.affiliation: EDF Research and Development, Laboratoire National d'Hydraulique et d'Environnement, Chatou Cedex, France. aurelie.touron-bodilis@edf.fr
authors.forename: A
authors.initials: A
authors.lastname: Touron-Bodilis
authors.forename: C
authors.initials: C
authors.lastname: Pougnard
authors.forename: H
authors.initials: H
authors.lastname: Frenkiel-Lebossé
authors.forename: S
authors.initials: S
authors.lastname: Hallier-Soulier
mesh_terms: D015169:Colony Count, Microbial; D004269:DNA, Bacterial / Q000235:genetics; D004202:Disinfectants; D004784:Environmental Monitoring / Q000379:methods; D007875:Legionella / Q000235:genetics / Q000302:isolation & purification*; D016952:Legionella pneumophila / Q000235:genetics / Q000302:isolation & purification*; D057230:Limit of Detection; D016133:Polymerase Chain Reaction / Q000379:methods*; D045483:Rivers / Q000382:microbiology; D014871:Water Microbiology; D014881:Water Supply
chemical_list: D004269:DNA, Bacterial; D004202:Disinfectants