Lins Renata Ximenes, Freitas Fernanda Santos, Vicente Ana Carolina Paulo
Federal Fluminense University, Post-Graduation Program in Dentistry, Healthy Institute of Nova Friburgo, Nova Friburgo, Brazil.
Instituto Oswaldo Cruz, Laboratório de Genética Molecular de Microrganismos, FIOCRUZ, Rio de Janeiro, Brazil.
Braz Dent J. 2024 Dec 16;35:e246104. doi: 10.1590/0103-644020246104. eCollection 2024.
Enterococcus faecalis is a common cause of nosocomial infections and is frequently associated with endodontic infections. However, there is a scarcity of studies addressing the genetic characterization of E. faecalis lineages most commonly associated with root canals. The aim of this study was to assess the genetic relatedness of E. faecalis strains from primary endodontic infections in Southeast Brazil, test the hypothesis of clones infecting unrelated individuals, and examine the antimicrobial resistance profile. The genetic relationship of 32 endodontic E. faecalis isolates was investigated using multilocus sequence typing (MLST). These isolates were collected from unrelated patients with primary endodontic infections treated in Brazil between 2010 and 2023. Antimicrobial susceptibility testing was performed using the disk diffusion method in accordance with the Clinical Laboratory Standards Institute guidelines. Twelve sequence types (STs) were detected, of which eight STs contained only a single strain. Clones of ST 30, ST 40, ST 97, and ST 397 were identified, with a notably high frequency of ST 397 (15/32). Susceptibility to the antimicrobial agents tested varied, with the highest resistance rates observed for clindamycin (100%), tetracycline (34.4%), azithromycin (31.2%), and ciprofloxacin (19.2%). One isolate was found to be multidrug-resistant. MLST analysis of endodontic E. faecalis revealed clones infecting different individuals in various cities over a span of up to 10 years, with a high occurrence of ST 397. Therefore, there appears to be a predominant E. faecalis lineage associated with endodontic infections in Southeast Brazil. These findings, together with existing literature, raise concerns that certain lineages may be specialized in causing endodontic infections.
粪肠球菌是医院感染的常见病因，且常与牙髓感染相关。然而，针对最常与根管相关的粪肠球菌谱系的基因特征研究却很匮乏。本研究的目的是评估巴西东南部原发性牙髓感染中粪肠球菌菌株的基因相关性，检验克隆感染无关个体的假设，并检测其抗菌药物耐药谱。使用多位点序列分型（MLST）研究了32株牙髓粪肠球菌分离株的基因关系。这些分离株是从2010年至2023年期间在巴西接受治疗的原发性牙髓感染的无关患者中收集的。根据临床实验室标准协会的指南，采用纸片扩散法进行抗菌药物敏感性测试。检测到12种序列类型（STs），其中8种STs每种仅包含一个菌株。鉴定出了ST 30、ST 40、ST 97和ST 397的克隆，其中ST 397的频率特别高（15/32）。对所测试抗菌药物的敏感性各不相同，观察到对克林霉素（100%）、四环素（34.4%）、阿奇霉素（31.2%）和环丙沙星（19.2%）的耐药率最高。发现有一株分离株对多种药物耐药。对牙髓粪肠球菌的MLST分析显示，在长达10年的时间里，克隆感染了不同城市的不同个体，且ST 397的发生率很高。因此，在巴西东南部似乎存在一种与牙髓感染相关的主要粪肠球菌谱系。这些发现与现有文献一起，引发了人们对某些谱系可能专门导致牙髓感染的担忧。
