급성치수염 및 급성 치근단 농양의 치근관으로부터의 세균 분리 및 DNA 분석법을 이용한 동정

Abstract

Isolation and identification of bacteria from acute endodontic infection lesions by 16S rDNA sequencing

Lee, Yeon-Jae, D.D.S., M.S.D. Advisor : Prof. Hwang, Ho-Keel, D.D.S., M.S.D., Ph. D. Department of Dentistry, Graduate School of Chosun University

  The aim of this study was to identify the bacteria isolated from acute endodontic infection lesions by cell culture and 16S rDNA sequencing. The necrotic pulpal tissue was collected from 17 infected root canals, which were diagnosed as being either an acute pulpitis or acute periapical abscess. Samples were collected aseptically from the infected pulpal tissue of the infected root canals using a barbed broach and a paper point. The cut barbed broaches and paper points were transferred to an eppendorf tube containing 500 ul of 1 X PBS. The sample solution was briefly mixed and plated onto a BHI-agar plate containing 5% sheep blood. The agar plates were incubated in a 37℃ anaerobic chamber for 7 days. The bacteria growing on the agar plate were identified by 16S rRNA coding gene (rDNA) cloning and sequencing at the species level. Seventy-one colonies grew on the agar plates. Of them, 56 strains survived and were identified. In dental caries involving the root canals, Streptococcus spp. were mainly isolated. Actinomyces, Clostridia, Bacteroides, and Fusobacteria were isolated in the periapical abscess lesion without dental caries. Interestingly, two new Actinomyces spp. (ChDC B639 and ChDC B631) were isolated in this study. These results showed that there was diversity among the species in endodontic infection lesions. This suggests that an endodontic infection is a mixed infection with a polymicrobial etiology. These results may offer the bacterial strains for pathogenesis studies related to an endodontic infection.