Culture-dependent approaches to explore the prevalence of root canal pathogens from endodontic infections

Abstract: Endodontic infections are considered to be caused by the presence of various microorganisms within the root canal system. Recognition of this microbiota contributes to the successful treatment of infected root canals. This study investigated the microorganisms associated with primary and secondary endodontic infections via culture methods, biochemical tests, and molecular approaches in an Iranian population. Microbial specimens were collected from 36 patients with primary endodontic infection and 14 patients with a history of root canal therapy. Advanced microbiological culture techniques were used to isolate microbiota; subsequently, biochemical tests and 16S ribosomal RNA gene sequencing were performed to identify the microorganisms. Within the total 218 cultivable isolates, Veillonella parvula (20.6%) was found to occur with the highest frequency in primary endodontic infection, followed by Porphyromonas gingivalis (14.1%), and Aggregatibacter actinomycetemcomitans (9.2%). Enterococcus faecalis (36.6%) was the most predominant microorganism in secondary endodontic infections, followed by Candida albicans, Propionibacterium acnes, and V. parvula with frequencies of 20%, 2%, and 2%, respectively. It was concluded that V. parvula and E. faecalis was most frequently found in primary and secondary endodontic infections, respectively.

摘要：牙髓感染（Endodontic infections）多由根管系统（root canal system）内定植的多种微生物引发。对该微生物群（microbiota）的精准识别是感染根管成功治疗的关键。本研究以伊朗人群为研究对象，采用培养法、生化检测及分子生物学手段，探究了与原发性和继发性牙髓感染相关的微生物类群。研究共采集36例原发性牙髓感染患者与14例有根管治疗史患者的微生物样本。通过先进的微生物培养技术分离得到目标微生物群，随后借助生化检测与16S核糖体RNA（16S ribosomal RNA）基因测序完成微生物鉴定。在总计218株可培养分离菌株中，小韦荣球菌（Veillonella parvula）在原发性牙髓感染中的检出率最高，达20.6%，其次为牙龈卟啉单胞菌（Porphyromonas gingivalis，14.1%）与伴放线聚集杆菌（Aggregatibacter actinomycetemcomitans，9.2%）。继发性牙髓感染中最优势的微生物为粪肠球菌（Enterococcus faecalis，36.6%），其次为白色念珠菌（Candida albicans）、痤疮丙酸杆菌（Propionibacterium acnes）与小韦荣球菌，检出率分别为20%、2%及2%。本研究最终结论：小韦荣球菌与粪肠球菌分别为原发性与继发性牙髓感染中最常见的致病微生物。