Comparative genomics identifies potential virulence factors in and .

Some well-known Clostridiales species such as and are agents of high impact diseases worldwide. Nevertheless, other foreseen Clostridiales species have recently emerged such as and . Three fecal isolates were identified as (Gcol.A2 and Gcol.A43) and (Gcol.A11) during public health screening for infections in Colombia. genomes were highly diverse and contained large numbers of accessory genes. Genetic diversity and accessory gene percentage were lower among the genomes than in the genomes. and toxins encoding homologous sequences and other potential virulence factors were also identified. interferase, a toxic component of the type II toxin-antitoxin system, was found among the genomes. was the only toxin encoding gene detected in Gcol.A43, the Colombian isolate with an experimentally-determined high cytotoxic effect. Gcol.A2 and Gcol.A43 had higher sporulation efficiencies than Gcol.A11 (84.5%, 83.8% and 57.0%, respectively), as supported by the greater number of proteins associated with sporulation pathways in the genomes compared with the genomes (33.3 and 28.4 on average, respectively). This work allowed complete genome description of two clostridiales species revealing high levels of intra-taxa diversity, accessory genomes containing virulence-factors encoding genes (especially in ), with proteins involved in sporulation processes more highly represented in . These finding suggest the need to advance in the study of those species with potential importance at public health level.