High abundance of novel environmental chlamydiae in a Tyrrhenian coastal lake (Lago di Paola, Italy)
Article first published online: 19 JUN 2012
© 2012 Society for Applied Microbiology and Blackwell Publishing Ltd
Environmental Microbiology Reports
Special Issue: Ecology, Evolution and Population Genetics of Pathogenic Microbes
Volume 4, Issue 4, pages 446–452, August 2012
How to Cite
Pizzetti, I., Fazi, S., Fuchs, B. M. and Amann, R. (2012), High abundance of novel environmental chlamydiae in a Tyrrhenian coastal lake (Lago di Paola, Italy). Environmental Microbiology Reports, 4: 446–452. doi: 10.1111/j.1758-2229.2012.00361.x
- Issue published online: 16 JUL 2012
- Article first published online: 19 JUN 2012
- Received 17 August, 2011; accepted 17 May, 2012.
For a long time the bacterial phylum of Chlamydiae exclusively consisted of one family of obligate intracellular bacteria, the Chlamydiaceae, which encompassed causative agents of severe diseases. In the 1990s, environmental chlamydiae were discovered as symbionts of free-living amoebae and other eukaryotic hosts. During a sampling campaign in September 2008, while monitoring Planctomycetes, we retrieved 20 almost full-length 16S rRNA gene sequences affiliated with Chlamydiales from a lake at the Tyrrhenian coast of central Italy (Lago di Paola, Latium). Two main clusters were identified. The nine sequences within the tight cluster I shared ∼98% identity, just like the six sequences of cluster II. The 16S rRNA sequence identity between the two novel groups was with 88% higher than with all known families of the order Chlamydiales. Four types of less frequent chlamydial 16S rRNA sequences were also detected. Two oligonucleotide probes were designed, and optimized. Chl282 targets the cluster I and almost all other Chlamydiales, while Chl282bis targets the cluster II and few other sequences. By catalysed reporter deposition fluorescence in situ hybridization (CARD-FISH), we identified in the Lago di Paola picoplankton abundant tiny cells with dot-shaped morphology and, interestingly, rarely also protists with intracellular pleomorphic chlamydiae. Abundances of the novel chlamydial clusters were up to 5 × 104 cells per millilitre. The two clusters were also detected in similar numbers during a second sampling in October 2010. This confirmed the relevance of the two newly described clusters of chlamydiae in Lago di Paola, not only enlarging the knowledge on the biodiversity of environmental chlamydiae in aquatic habitats, but also raising sanitary issues that should be addressed in the future.