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.<br /><br />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.<br /><br />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.
Conza, L., Casati, S., & Gaia, V. (2013). Detection limits of Legionella pneumophila in environmental samples after co-culture with Acanthamoeba polyphaga. BMC Microbiology, 13(1). https://doi.org/10.1186/1471-2180-13-49