[ODP30] 7. 抗菌性物質・薬剤耐性-a. 抗菌性物質

[ODP-194] Complete sequences of bacteriocin plasmids of S. epidermidis and their antibacterial activity

松尾 美樹^1,2，レ グェントラ ミ^1,2，久恒 順三^2,3，菅井 基行^2,3，小松澤 均^1,2 (¹広島大・医系科学・細菌学，²広島大・院内感染研究センター，³感染研・薬剤耐性センター)

Staphylococcus epidermidis is a commensal bacterium in humans. To persist in the bacterial flora, some bacteria produce antibacterial factors such as bacteriocins. In this study, we tried to isolate bacteriocin-producing S. epidermidis strains. Among 150 S. epidermidis isolates from the oral cavities of 287 volunteers, we detected two bacteriocin-producing strains, KSE56 and KSE650. Complete genome sequences of the two strains confirmed that they carried the epidermin-harbouring plasmid pEpi56 and the nukacin IVK45-like-harbouring plasmid pNuk650. The amino acid sequence of epidermin from KSE56 was identical to the previously reported sequence, but the epidermin synthesis-related genes were partially different. The prepeptide amino acid sequences of nukacin KSE650 and nukacin IVK45 showed one mismatch, but both mature peptides were entirely similar. pNuk650 was larger and had an additional seven ORFs compared to pIVK45. We then investigated the antibacterial activity of the two strains against several skin and oral bacteria and found their different activity patterns. In conclusion, we report the complete sequences of 2 plasmids coding for bacteriocins from S. epidermidis, which were partially different from those previously reported. Furthermore, this is the first report to show the complete sequence of an epidermin-carrying plasmid, pEpi56.