Special Department, School and Hospital of Stomatology, Peking University, Beijing, China.
J Endod. 2010 Dec;36(12):1950-5. doi: 10.1016/j.joen.2010.08.053. Epub 2010 Oct 16.
The aim of this study was to investigate the prevalence, phenotype, and genotype of Enterococcus faecalis isolated from saliva and root canals in patients with endodontic treatment failure.
Samples were collected from 32 adults undergoing retreatment for periapical lesions after endodontic treatment performed at least 2 years previously. Isolates that were presumed to be E. faecalis were identified by both API20 Strep kits and 16S rRNA sequencing. Phenotypic tests for hemolysin and gelatinase production and antibiotic susceptibility were performed. Genotype analysis comprised virulence gene detection and pulsed field gel electrophoresis (PFGE).
The prevalence of E. faecalis was 18.8% in saliva and 40.6% in root canals (P = .666, Fisher exact test). Of the 19 isolates of E. faecalis, 6 were from saliva and 13 were from root canals. In 3 patients, E. faecalis isolates from saliva were more resistant to gentamicin than those from root canals. The genes ace, asa, gelE, cylA, and efaA were detected from all isolates. PFGE after SmaI digestion showed a genetic correlation among all isolates of 62%-100%.
Phenotype and genotype evidence of potential virulence factors was identified in E. faecalis from both saliva and root canals. A single patient might carry different E. faecalis strains in saliva and root canals.
本研究旨在调查在根管治疗失败的患者的唾液和根管中分离出粪肠球菌的流行率、表型和基因型。
从 32 名接受根管再治疗的成年人中收集样本，这些患者在根管治疗至少 2 年后出现根尖病变。通过 API20 Strep 试剂盒和 16S rRNA 测序鉴定假定为粪肠球菌的分离株。进行溶血素和明胶酶产生及抗生素敏感性的表型试验。基因型分析包括毒力基因检测和脉冲场凝胶电泳（PFGE）。
唾液中粪肠球菌的流行率为 18.8%，根管中为 40.6%（P =.666，Fisher 确切检验）。在 19 株粪肠球菌中，有 6 株来自唾液，13 株来自根管。在 3 名患者中，来自唾液的粪肠球菌对庆大霉素的耐药性高于来自根管的粪肠球菌。所有分离株均检测到 ace、asa、gelE、cylA 和 efaA 基因。经 SmaI 消化的 PFGE 显示所有分离株的遗传相关性为 62%-100%。
在唾液和根管中分离出的粪肠球菌均存在潜在毒力因子的表型和基因型证据。同一患者的唾液和根管中可能携带不同的粪肠球菌菌株。
