Comparative genomic analysis reveals distinct population structure in Legionella anisa.

Genomic analysis uncovers three distinct, highly divergent populations of Legionella anisa, with a clonal lineage identified in a Canadian healthcare facility.

• Why it matters: Understanding the population structure of L. anisa is crucial because it is frequently found in water systems and may pose health risks, yet its genetic diversity remains poorly characterized compared to other Legionella species.
• What they did: Four complete genomes from Rimouski isolates were sequenced and compared with publicly available genomes, revealing three clades separated by approximately 500 SNPs and a highly variable accessory genome (~50%).
• The result: Findings highlight significant genetic diversity and environmental adaptation features, such as plasmids with resistance genes, and demonstrate variable proliferation in protozoan hosts, informing future studies on persistence and pathogenicity.