title: Detection limits of Legionella pneumophila in environmental samples after co-culture with Acanthamoeba polyphaga.
abstract: BACKGROUND
  The efficiency of recovery and the detection limit of Legionella after co-culture with Acanthamoeba polyphaga are not known and so far no investigations have been carried out to determine the efficiency of the recovery of Legionella spp. by co-culture and compare it with that of conventional culturing methods. This study aimed to assess the detection limits of co-culture compared to culture for Legionella pneumophila in compost and air samples. Compost and air samples were spiked with known concentrations of L. pneumophila. Direct culturing and co-culture with amoebae were used in parallel to isolate L. pneumophila and recovery standard curves for both methods were produced for each sample.
  
  
  RESULTS
  The co-culture proved to be more sensitive than the reference method, detecting 10²-10³ L. pneumophila cells in 1 g of spiked compost or 1 m³ of spiked air, as compared to 10⁵-10⁶ cells in 1 g of spiked compost and 1 m³ of spiked air.
  
  
  CONCLUSIONS
  Co-culture with amoebae is a useful, sensitive and reliable technique to enrich L. pneumophila in environmental samples that contain only low amounts of bacterial cells.
authors: Swiss National Reference Centre for Legionella, Cantonal Institute of Microbiology, Via Mirasole 22a, 6500, Bellinzona, Switzerland. lisa.conza@ti.ch
authors: Lisa
authors: L
authors: Conza
authors: Simona
authors: S
authors: Casati
authors: Valeria
authors: V
authors: Gaia
mesh_terms: D000048:Acanthamoeba / Q000254:growth & development / Q000382:microbiology*; D000391:Air Microbiology; D001431:Bacteriological Techniques / Q000379:methods*; D018920:Coculture Techniques; D016952:Legionella pneumophila / Q000302:isolation & purification*; D057230:Limit of Detection; D012988:Soil Microbiology