Methods: WGS was performed on the BF-EIEC 52.1 strain using NextGen Illumina and Pacific Biosciences (PacBio) platforms. Publically available genomes from other EIEC O96H19 and Shigella genomes previously published were analyzed using online available software and databases including NCBI, BLAST, Mauve, among others. This analysis was tailored to identify virulence factors from the virulence factor database (VFDB). BLASTn was used to determine identity and query coverage of genes encoding the Shigella virulence factors. EIEC and Shigella genomes were analyzed on a multiple genome alignment software (Mauve) to verify results from BLASTn and to determine pseudogenes.
Results: The genome of EIEC O96:H19 strain 52.1 was 5,193,449 bp in size, containing 5,050 coding DNA sequences (CDSs). O96:H19 strain 52.1 carries three plasmids, the invasion plasmid (pINV) contains all type 3 secretion system (TTSS) and TTSS effectors genes previously described for Shigella and EIEC O96:H19 CFSAN029787 Italian strain. Non-TTSS virulence genes were also identified, including: long polar fimbrial gene (IpfA), enterotoxin (senB), and antibiotic resistance genes.
Conclusion: The EIEC O96:H19 strain 52.1 genome carries TTSS genes within a virulence plasmid, protein effector genes, and enterotoxin genes known to be associated with EIEC virulence. The EIEC O96:H19 stain 52.1 is an emergent diarrheagenic pathogen likely derived from an E. coli O96:H19 strain that acquired a Shigella-like virulence plasmid by horizontal transfer.
R. Ko, None