Department of Microbiology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil.
J Endod. 2011 Jul;37(7):922-6. doi: 10.1016/j.joen.2011.04.007.
The characterization of microbial communities infecting the endodontic system in each clinical condition may help on the establishment of a correct prognosis and distinct strategies of treatment. The purpose of this study was to determine the bacterial diversity in primary endodontic infections by 16S ribosomal-RNA (rRNA) sequence analysis.
Samples from root canals of untreated asymptomatic teeth (n = 12) exhibiting periapical lesions were obtained, 16S rRNA bacterial genomic libraries were constructed and sequenced, and bacterial diversity was estimated.
A total of 489 clones were analyzed (mean, 40.7 ± 8.0 clones per sample). Seventy phylotypes were identified of which six were novel phylotypes belonging to the family Ruminococcaceae. The mean number of taxa per canal was 10.0, ranging from 3 to 21 per sample; 65.7% of the cloned sequences represented phylotypes for which no cultivated isolates have been reported. The most prevalent taxa were Atopobium rimae (50.0%), Dialister invisus, Prevotella oris, Pseudoramibacter alactolyticus, and Tannerella forsythia (33.3%).
Although several key species predominate in endodontic samples of asymptomatic cases with periapical lesions, the primary endodontic infection is characterized by a wide bacterial diversity, which is mostly represented by members of the phylum Firmicutes belonging to the class Clostridia followed by the phylum Bacteroidetes.
在每种临床情况下，对感染牙髓系统的微生物群落进行特征分析，可能有助于确定正确的预后，并制定出不同的治疗策略。本研究旨在通过 16S 核糖体 RNA（rRNA）序列分析，确定原发性牙髓感染中的细菌多样性。
从无临床症状的根尖周病变未治疗的牙根管中获得样本，构建和测序 16S rRNA 细菌基因组文库，并估计细菌多样性。
共分析了 489 个克隆（每个样本平均 40.7 ± 8.0 个克隆）。共鉴定出 70 个菌群，其中 6 个为新型菌群，属于瘤胃球菌科。每个根管的平均分类单元数为 10.0，每个样本范围为 3 至 21；65.7%的克隆序列代表尚未培养分离的菌群。最常见的菌群为阿托波氏菌（50.0%）、不可见消化链球菌、口腔普氏菌、假迟缓真杆菌和福赛坦纳氏菌（33.3%）。
尽管在有根尖周病变的无症状病例的牙髓样本中，有几个关键物种占主导地位，但原发性牙髓感染的特征是具有广泛的细菌多样性，主要由厚壁菌门的梭菌纲成员组成，其次是拟杆菌门。
