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Molecular analysis of persistent periradicular lesions and root ends reveals a diverse microbial profile
Kumar Subramanian1, Andre K Mickel
1Department of Endodontics, College of Dentistry, Case Western Reserve University, Cleveland, OH, USA. drskumars@gmail.com
Introduction:
The microbial etiology of periradicular lesions is recognized; however, the bacterial profile of these lesions is not well elucidated. The purpose of this study was to determine the frequency of bacterial colonization in these lesions and to characterize the bacterial community present in root ends and periradicular lesions.
Methods:
Thirty-four adult patients who presented for apicoectomy of persistent periradicular lesions after endodontic therapy were selected for the study and samples of periradicular tissue and resected root ends collected. Total bacterial levels were estimated for 34 paired periradicular lesions and root ends using real-time polymerase chain reaction with universal bacterial primers. Sixteen pairs of these samples were analyzed using ribosomal 16S cloning and sequencing for bacterial identification.
Results:
Bacteria were detected more consistently and at higher levels in root ends. Periradicular lesions exhibited a diverse microbial profile with many uncultivated phylotypes. Enterococcus faecalis and Burkholderia cepacia predominated in both samples. Campylobacter gracilis and Streptococcus gordonii were associated with root ends, whereas Atopobium rimae, Peptostreptococcus micros, Streptococcus genomospecies C8, Dialister sp E2_20 E1, and Eubacterium strain A35MT were associated with periradicular lesions.
Conclusions:
Persistent periradicular lesions are polymicrobial infections with many as-yet-uncultivated and unknown bacterial species. The bacterial load and microbial profile of root ends is significantly different from the soft-tissue lesion, indicating the presence of diverse bacterial populations in these tissues.
Insights
Persistent periradicular lesions harbor diverse bacteria, with distinct microbial communities found in root ends versus lesion tissue. Understanding these polymicrobial infections is crucial for effective treatment.
Area of Science:
- Microbiology
- Endodontics
- Oral Health
Background:
- The microbial cause of periradicular lesions is known, but their specific bacterial composition remains unclear.
- This study aimed to investigate the bacterial communities within root ends and associated periradicular lesions.
Purpose of the Study:
- To determine the frequency of bacterial colonization in periradicular lesions.
- To characterize the specific bacterial species present in root ends and periradicular lesions.
Main Methods:
- Collected tissue and root end samples from 34 patients undergoing apicoectomy for persistent periradicular lesions.
- Quantified total bacterial levels using real-time polymerase chain reaction (PCR).
- Identified bacterial species in 16 samples via ribosomal 16S cloning and sequencing.
Main Results:
- Bacteria were more prevalent and abundant in root ends compared to periradicular lesions.
- Periradicular lesions displayed a diverse microbial profile, including many uncultivated bacteria.
- Key species identified included Enterococcus faecalis and Burkholderia cepacia, with distinct bacteria associated with root ends versus lesions.
Conclusions:
- Persistent periradicular lesions represent complex polymicrobial infections.
- The bacterial load and community structure differ significantly between root ends and soft-tissue lesions.
- Many bacterial species within these lesions remain uncultivated and unidentified, highlighting the need for further research.
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