Bouillaguet Serge, Manoil Daniel, Girard Myriam, Louis Justine, Gaïa Nadia, Leo Stefano, Schrenzel Jacques, Lazarevic Vladimir
Endodontics Unit, Section of Dental Medicine, Faculty of Medicine, University of Geneva, Geneva, Switzerland.
Faculty of Medicine, Genomic Research Laboratory, Service of Infectious Diseases, Geneva University Hospitals, Geneva, Switzerland.
Front Microbiol. 2018 Oct 9;9:2374. doi: 10.3389/fmicb.2018.02374. eCollection 2018.
Apical periodontitis is an inflammatory disease of the dental periradicular tissues triggered by bacteria colonizing necrotic root canals. Primary apical periodontitis results from the microbial colonization of necrotic pulp tissues. Secondary apical periodontitis results from a persistent infection of incorrectly treated root canals. The aim of this study was to characterize the microbiota present in primary and secondary intraradicular infections associated with apical periodontitis using 16S rRNA gene amplicon sequencing. Teeth exhibiting apical periodontitis with or without root canal treatment were extracted after informed consent. From each tooth, the intraradicular content as well as a dentin sample (control) were collected and subjected to DNA extraction. PCR amplicons of the V3-V4 region of the bacterial 16S rRNA gene were pooled and sequenced (2 × 300) on an Illumina MiSeq instrument. The bioinformatics analysis pipeline included quality filtering, merging of forward and reverse reads, clustering of reads into operational taxonomic units (OTUs), removal of putative contaminant OTUs and assigning taxonomy. The most prevalent and abundant OTU in both dentin and root canal samples was assigned to anaerobic bacterium . Multivariate analysis showed clustering of microbiota by sample type (dentin vs. intraradicular content) and, in root canals, by pathology (primary vs. secondary infection). The proportions of and were, respectively, higher and lower when comparing secondary to primary infected root canals. Co-occurrence network analysis provided evidence of microbial interactions specific to the infection type. The identification of bacterial taxa differentially abundant in primary and secondary intraradicular infections may provide the basis for targeted therapeutic approaches aimed at reducing the incidence of apical periodontitis.
根尖周炎是一种由定植于坏死根管的细菌引发的牙髓根尖周组织炎症性疾病。原发性根尖周炎由坏死牙髓组织的微生物定植引起。继发性根尖周炎由根管治疗不当导致的持续性感染引起。本研究的目的是使用16S rRNA基因扩增子测序来表征与根尖周炎相关的原发性和继发性根管内感染中存在的微生物群。在获得知情同意后，拔除患有或未患根尖周炎且有或无根管治疗的牙齿。从每颗牙齿中收集根管内容物以及牙本质样本（对照）并进行DNA提取。将细菌16S rRNA基因V3-V4区域的PCR扩增子混合，并在Illumina MiSeq仪器上进行测序（2×300）。生物信息学分析流程包括质量过滤、正向和反向读段合并、将读段聚类为操作分类单元（OTU）、去除假定的污染OTU以及分类学归属。牙本质和根管样本中最普遍且丰度最高的OTU被归为厌氧菌。多变量分析显示，微生物群按样本类型（牙本质与根管内容物）聚类，在根管中按病理类型（原发性与继发性感染）聚类。与原发性感染的根管相比，继发性感染的根管中[具体细菌名称1]和[具体细菌名称2]的比例分别更高和更低。共现网络分析提供了特定于感染类型的微生物相互作用的证据。鉴定原发性和继发性根管内感染中差异丰富的细菌分类群可能为旨在降低根尖周炎发病率的靶向治疗方法提供依据。
