Molecular analysis of bacteria in asymptomatic and symptomatic endodontic infections

Abstract

The purpose of the present study was to use terminal restriction fragment length polymorphism analysis and the 16S rRNA gene clone library to investigate the diversity of the microbiota associated with asymptomatic and symptomatic endodontic infections and to compare the bacterial community structure in these two clinical conditions. Samples were taken from asymptomatic endodontic infections associated with chronic periradicular lesions and from symptomatic infections clinically diagnosed as acute abscesses. 16S rRNA genes from DNA isolated from clinical samples were used to construct clone libraries or were subjected to terminal restriction fragment length polymorphism analysis. Sequence analysis of 186 clones revealed 42 taxa; 23 (55%) were uncultivated phylotypes, of which seven were unique to endodontic infections. Clone sequencing and terminal restriction fragment length polymorphism analysis revealed that the most commonly detected taxa were Fusobacterium nucleatum (including terminal restriction fragment types 1 and 2), Peptostreptococcus micros/Peptostreptococcus sp. oral clone AJ062/BS044/FG014, Prevotella species, Dialister species, Mogibacterium species, Lachnospiraceae oral clone 55A-34, Filifactor alocis, Megasphaera sp. oral clone CS025/BS073, and Veillonella sp. oral clone BP1-85/Veillonella dispar/V. parvula. Bacteroides-like sp. oral clone X083/Bacteroidales oral clone MCE7_20 and Dialister sp. oral clone BS016/MCE7_134 were detected only in asymptomatic teeth. On the other hand, F. nucleatum terminal restriction fragment type 2, Prevotella intermedia, Dialister pneumosintes, and some phylotypes were exclusively detected in symptomatic samples. Bacterial profiles of symptomatic endodontic infections generated by terminal restriction fragment length polymorphism analysis were clearly different from those of asymptomatic infections. Overall, the average number of terminal restriction fragments in symptomatic samples was significantly larger than in asymptomatic samples. Molecular analysis of the microbiota associated with symptomatic or asymptomatic endodontic infections indicates that the endodontic bacterial diversity is greater than previously described by culture methods and that the structure of the microbiota differ significantly between asymptomatic and symptomatic infections.

Diversity of Spirochetes in Endodontic Infections

“…Most of the previous molecular studies focused on the detection of selected Treponema species or phylotypes (4, 11, 13, 15, 25-27, 38, 40, 43, 46). Of the several studies that have performed broad-range analyses for overall bacteria in primary endodon- (41) 2 (6) 8 (11 (14, 22, 29, 31-33, 52, 53), only two reported the occurrence of spirochetes, and even those were a few species in a few cases (31,32). These studies using universal bacterial primers may underestimate spirochetal populations, especially if they are in low numbers in the environment (5,16).…”

“…Nine samples positive for the spirochete-specific primers and exhibiting the strongest bands in the agarose gel were selected for further 16S rRNA gene clone library analysis (32). PCR products were purified using an UltraClean PCR Clean-up DNA purification kit (Mo Bio Laboratories, Inc., CA).…”

Study Comparing the Effectiveness of Chlorhexidine, Calcium Hydroxide and Linezolid Based Medicaments Against Enterococcus Faecalis

“…However, some have documented its occurrence in primary as well as secondary endodontic lesions [1,29]. EF can survive inside dentin tubules for atleast 10 days without nutrient supply [16,30].…”

Bacterial diversity of subgingival plaque in 6 healthy Chinese individuals

“…Over half of the species detected have not yet been cultivated (6). Data from these studies have implicated specific species or phylotypes in a variety of diseases and oral infections (4,(9)(10)(11)(12)(13), but still only limited information is available on species in subgingival plaque of healthy subjects. Moreover, to date, culture-independent studies describing the bacterial community of subgingival plaque in Chinese individuals are limited.…”