title: Detection of transient bacteraemia following dental extractions by 16S rDNA pyrosequencing: a pilot study.
abstract: OBJECTIVE
  The current manuscript aims to determine the prevalence, duration and bacterial diversity of bacteraemia following dental extractions using conventional culture-dependent methods and 16S rDNA pyrosequencing.
  
  
  METHODS
  The study group included 8 patients undergoing dental extractions under general anaesthesia. Peripheral venous blood samples were collected at baseline, 30 seconds and 15 minutes after the dental extractions. Blood samples were analysed for bacteraemia applying conventional microbiological cultures under aerobic and anaerobic conditions as well as pyrosequencing using universal bacterial primers that target the 16S ribosomal DNA gene.
  
  
  RESULTS
  Transient bacteremia was detected by culture-based methods in one sample at baseline time, in eight samples at 30 seconds, and in six samples at 15 minutes after surgical procedure; whereas bacteraemia was detected only in five blood samples at 30 seconds after dental extraction by using pyrosequencing. By applying conventional microbiological methods, a single microbial species was detected in six patients, and Streptococcus viridans was the most frequently cultured identified bacterium. By using pyrosequencing approaches however, the estimated blood microbial diversity after dental extractions was 13.4±1.7 bacterial families and 22.8±1.1 genera per sample.
  
  
  CONCLUSIONS
  The application of 16S rDNA pyrosequencing underestimated the prevalence and duration of bacteraemia following dental extractions, presumably due to not reaching the minimum DNA required for PCR amplification. However, this molecular technique, unlike conventional culture-dependent methods, revealed an extraordinarily high bacterial diversity of post-extraction bacteraemia. We propose that microorganisms recovered by culture may be only the tip of an iceberg of a really diverse microbiota whose viability and potential pathogenicity should be further studied.
authors.affiliation: Genomics and Health Department, Centre for Advanced Research in Public Health, CSISP, Valencia, Spain.
authors.forename: Alfonso
authors.initials: A
authors.lastname: Benítez-Páez
authors.forename: Maximiliano
authors.initials: M
authors.lastname: Álvarez
authors.forename: Pedro
authors.initials: P
authors.lastname: Belda-Ferre
authors.forename: Susana
authors.initials: S
authors.lastname: Rubido
authors.forename: Alex
authors.initials: A
authors.lastname: Mira
authors.forename: Inmaculada
authors.initials: I
authors.lastname: Tomás
mesh_terms: D000328:Adult; D016470:Bacteremia / Q000175:diagnosis / Q000382:microbiology*; D044822:Biodiversity; D015169:Colony Count, Microbial; D004275:DNA, Ribosomal; D005260:Female; D005881:Gingiva / Q000382:microbiology*; D006801:Humans; D008297:Male; D054892:Metagenome; D010865:Pilot Projects; D017422:Sequence Analysis, DNA; D013290:Streptococcal Infections / Q000175:diagnosis / Q000382:microbiology*; D014081:Tooth Extraction; D034363:Viridans Streptococci / Q000235:genetics* / Q000302:isolation & purification
chemical_list: D004275:DNA, Ribosomal