2020 Volume 55 Issue 1 Pages 18-21
Pseudotuberculosis pathogen, Photobacterium damselae subsp. piscicida (Pdp) shows some differences in virulence between Japanese and US strains. In this study, we analyzed plasmid DNAs derived from Japanese and US strains of Pdp, and found two homologous regions in these plasmids, pOT-51443-4/p91-197-1 and pOT-51443-1/p91-197-2. All genes in the p91-197-1 from US strain were observed in the pOT-51443-4 from Japanese strain. This event might have occurred during transmission of the US plasmid to Japanese strain. Inhibitor of vertebrate lysozyme (ivy), a known pathogenicity factor was encoded in the homologous region of pOT-51443-1/p91-197-2. Thus, the genomic region containing ivy may have been horizontally transmitted between the two Pdp strains.