Get to Know Your Neighbors: Characterization of Close Isolates and Toxin Profile Diversity in the Group

Unexpected atypical isolates of occasionally challenge conventional microbiology and even the most advanced techniques for anthrax detection. For anticipating and gaining trust, 65 isolates of of diverse origin were sequenced and characterized. The BTyper3 tool was used for assignation to genomospecies (34), (29) and (2), as well as virulence factors and toxin profiling. None of them carried any capsule or anthrax-toxin genes. All harbored the non-hemolytic toxin and sphygomyelinase genes, whereas 41 (63%), 30 (46%), 11 (17%) and 6 (9%) isolates harbored , , and at least one insecticidal toxin gene, respectively. Matrix-assisted laser desorption ionization-time of flight mass spectrometry confirmed the production of cereulide ( genes). Phylogeny inferred from single-nucleotide polymorphisms positioned isolates relative to the lineage. One isolate (BC38B) was of particular interest as it appeared to be the closest neighbor described so far. It harbored a large plasmid similar to other previously described megaplasmids and at a lower extent to pXO1. Whereas bacterial collection is enriched, these high-quality public genetic data offer additional knowledge for better risk assessment using future NGS-based technologies of detection.