Open Access Highly Accessed Open Badges Research article

Detection limits of Legionella pneumophila in environmental samples after co-culture with Acanthamoeba polyphaga

Lisa Conza*, Simona Casati and Valeria Gaia

Author Affiliations

Swiss National Reference Centre for Legionella, Cantonal Institute of Microbiology, Via Mirasole 22a, 6500, Bellinzona, Switzerland

For all author emails, please log on.

BMC Microbiology 2013, 13:49  doi:10.1186/1471-2180-13-49

Published: 26 February 2013



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.


The co-culture proved to be more sensitive than the reference method, detecting 102-103‚ÄČL. 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.


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.

Legionella; Culture; Co-culture; Compost; Air; Bioaerosol; Detection limit