Department of Dental Medicine, Karolinska Institutet, Huddinge, Sweden.
Lett Appl Microbiol. 2011 Feb;52(2):109-15. doi: 10.1111/j.1472-765X.2010.02972.x. Epub 2010 Dec 13.
Enterococcus faecalis is associated with a significant number of refractory endodontic infections. Previous studies report a prevalence of Ent. faecalis ranging from 24% up to 77% in teeth with failed endodontic treatment. The origin of the micro-organism remains unclear, as enterococci do not belong to the normal oral microflora. The aim of this study was to determine whether these enterococci were of endogenous or exogenous origin.
Fifty consecutive patients with apical periodontitis in need of endodontic orthograde re-treatment were included. Samples were collected from root canals, saliva and faeces and subjected to microbiological culturing. The genetic relationship between Ent. faecalis from root canals and isolates from the different host sources was determined using pulsed-field gel electrophoresis. In 16% (8/50) of the patients, enterococci were collected from the root canal samples. The genetic analysis showed that the isolates from the root canals were not related to those from the normal gastrointestinal microflora. None of these patients had enterococci in their saliva samples.
Endodontic infections with Ent. faecalis are probably not derived from the patient's own normal microflora, which indicates that these infections ent. faecalis are of exogenous origin.
This is the first study to genetically compare endodontic infectious Ent. faecalis isolates with isolates from the hosts' own normal microflora.
粪肠球菌与大量难治性根管感染有关。先前的研究报告显示，在根管治疗失败的牙齿中，粪肠球菌的患病率为 24%至 77%。该微生物的来源尚不清楚，因为肠球菌不属于正常口腔微生物群。本研究旨在确定这些肠球菌是内源性还是外源性的。
连续纳入 50 例需要根管正向再治疗的根尖周炎患者。从根管、唾液和粪便中采集样本进行微生物培养。使用脉冲场凝胶电泳确定根管中粪肠球菌与不同宿主来源的分离株之间的遗传关系。在 16%（8/50）的患者中，从根管样本中采集到肠球菌。遗传分析表明，根管分离株与正常胃肠道微生物群无关。这些患者的唾液样本中均未发现肠球菌。
根管感染的粪肠球菌可能不是来源于患者自身的正常微生物群，这表明这些感染的肠球菌是外源性的。
这是第一项在遗传上比较根管感染的粪肠球菌分离株与宿主自身正常微生物群分离株的研究。
