Faucher SP, Matthews S, Nickzad A, Vounba P, Shetty D, Bédard É, Prévost M, Déziel E, Paranjape K. Toxoflavin secreted by Pseudomonas alcaliphila inhibits the growth of Legionella pneumophila and Vermamoeba vermiformis. Water Res. 2022 Jun 1;216:118328. doi: 10.1016/j.watres.2022.118328. Epub 2022 Mar 19. PMID: 35364354.
Highlights
- Most large outbreaks are caused by cooling towers colonised with pneumophila.
- The resident microbiota of the cooling tower is a key determinant for the colonisation and growth of pneumophila.
- Cooling towers that are free of pneumophila contained a high relative abundance of members from the Pseudomonas alcaliphila/oleovorans phylogenetic cluster.
- alcaliphila inhibited the growth of L. pneumophila on agar plates and analysis of it’s genome revealed the presence of a gene cluster predicted to produce toxoflavin.
- pneumophila growth was inhibited by pure toxoflavin and by extracts from P. alcaliphila culture found to contain toxoflavin.
- Toxoflavin also inhibits the growth of Vermameoba vermiformis, a host cell of pneumophila.
- A sufficiently high concentration of toxoflavin is likely not achieved in the bulk water but might have a local inhibitory effect such as near or in biofilms.