再治疗根管内粪肠球菌的分离鉴定及其相关特性研究

目的:研究粪肠球菌在再治疗根管内的检出率及其相关特性(生长情况、生物膜形成能力及耐药性)。方法:收集临床病例样本54例,使用粪肠球菌选择性培养基和胆盐七叶苷琼脂进行分离培养。分离株通过16SrRNA测序法鉴定。将鉴定正确的粪肠球菌临床分菌株和作为对照的粪肠球菌标准株(EfATCC29212)用BHI培养基进行培养,分别对比其生长曲线、生物膜形成能力及耐药性。结果:收集临床病例样本54例,分离鉴定为粪肠球菌的有18例,检出率为33.33%。经统计分析:粪肠球菌在再治疗根管内的检出率在病人性别、年龄、患牙尖周稀疏大小及距离上次根管治疗时间长短等方面无统计学差异(P>0.05);但与上次根管治疗根充是否到位有关,欠填根管中粪肠球菌的检出率明显高于恰填根管(P<0.05),但不同欠填长度组间粪肠球菌的检出率无统计学差异(P>0.05)。此外,粪肠球菌临床分离株与对照菌株在生长曲线、生物膜形成能力及耐药性等方面均无统计学差异(P>0.05)。结论:粪肠球菌在再治疗根管内的检出率为33.33%,其检出率与上次根管治疗根充情况有关。同时,粪肠球菌临床分离株与标准株的生长情况、生物膜形成能力及耐药性基本一致。

Isolation and characterization of Enterococcus Faecalis from retreated root canals

AIM: To study the prevalence of Enterococcus faecalis in the root canals after failure of root canal therapy and the characteristics of the clinical isolated strains.METHODS: Fifty-four clinical samples were collected.Enterococcus faecalis were selectively cultured by SF medium and Enterococcus faecalis agar.The isolated Enterococcus faecalis strains were confirmed by the 16SrRNA sequencing.And the characteristics(such as the growth character,the abilities of biofilm formation and drug resistance) of the isolated strains were tested and compared.The standard strain of the Enterococcus faecalis,E.f 29212,was used as positive control.RESULTS: Fifty-four clinical samples were collected and 18 strains were selected and confirmed as Enterococcus faecalis.The prevalence of Enterococcus faecalis in the root canals after failure of root canal therapy was 33.33%.No significant prevalence difference was found between gender,age,diameter of the lesion around the root apex and the interval after pretreatment.However,the prevalence of Enterococcus faecalis was significantly higher when the root filling was shorter than the working length(P=0.013).But there was no statistical difference among the limited-filled groups.The clinically isolated strain showed no statistical difference with the control strain in growth,biofilm formation and drug resistance.CONCLUSION: The prevalence of Enterococcus faecalis in the root canals after root canal therapy failure was 33.33% and there was corelation between the prevalence and the root filling condition of the pretreatment.It was higher when the root filling was shorter than the working length.There was no statistical difference in growth,biofilm formation and drug resistance between the isolated strains and the control strain.