Grandbastien B, Mauffrey F, Greub G, Blanc DS. Appl Environ Microbiol 91:e01147-25.
Highlights:
- ISO 11731:2017 covers culture-based methods for Legionella detection in water using a matrix of tests and advises considering the least favourable outcome.
- This study evaluated six techniques from the matrix, applied to 276 hospital hot water samples.
- Legionella was detected in 120 samples, with substantial variability across methods.
- The most sensitive single technique (76%) was concentration and elution with membrane filter on GVPC medium after heat treatment.
- Combinations of three techniques yielded a higher detection rate (98%), while using all six techniques detected all positive samples.
- Techniques involving concentration and elution proved superior to direct plating or simple filtration.
- Heat treatment enhanced detection more effectively than acid treatment, especially in samples with interfering flora.
- GVPC medium consistently outperformed BCYE.
- In summary the researchers highlight the superiority of methods involving concentration, membrane filtration, and heat treatment—particularly those using GVPC medium.
