title: Endodontic bacteria from primary and persistent endodontic lesions in Chinese patients as identified by cloning and 16S ribosomal DNA gene sequencing.
abstract: BACKGROUND
  Few literatures pertain to the 16S ribosomal DNA (16S rDNA) analysis of bacteria contributing to primary and persistent endodontic lesions, with no information available for the Chinese population. As such, we investigated endodontic bacteria associated with primary and persistent endodontic lesions in adult Chinese patients living in Beijing, China using 16S rDNA gene sequencing techniques.
  
  
  METHODS
  Endodontic microbial samples were obtained from fourteen adult Chinese patients and subjected to DNA extraction. Pllymerase chain reaction (PCR) products were cloned and 100 clones from each generated library were randomly selected. Purified plasmid DNA with 16S rDNA gene inserts was sequenced, and the sequences were searched against GenBank databases using the BLASTN algorithm. Only significant identification with the highest-scored BLAST result and 99% minimum similarity was considered for phylotyping.
  
  
  RESULTS
  More than 150 taxa were obtained. Primary endodontic infection was mainly associated with Burkholderia cepacia, Actinomyces, Aranicola spp. and Streptococcus sanguinis, whilst Burkholderia cepacia was predominant in the persistent endodontic infections.
  
  
  CONCLUSIONS
  There is a difference in the species profile associated with endodontic infections of Chinese patients living in Beijing in comparison to other geographical or ethnic reports.
authors: Faculty of Dentistry, Peking University Third Hospital, Beijing, 100191, China.
authors: Xin
authors: X
authors: Li
authors: Xiao-fei
authors: XF
authors: Zhu
authors: Cheng-fei
authors: CF
authors: Zhang
authors: Peter
authors: P
authors: Cathro
authors: C J
authors: CJ
authors: Seneviratne
authors: Song
authors: S
authors: Shen
mesh_terms: D001419:Bacteria / Q000145:classification / Q000235:genetics / Q000472:pathogenicity*; D002681:China; D004269:DNA, Bacterial / Q000235:genetics; D004275:DNA, Ribosomal / Q000235:genetics*; D005260:Female; D006801:Humans; D008297:Male; D011671:Pulpitis / Q000382:microbiology*; D017422:Sequence Analysis, DNA / Q000379:methods*
chemical_list: D004269:DNA, Bacterial; D004275:DNA, Ribosomal