Diverse and Novel Oral Bacteria in Blood Following Dental Procedures

It has been estimated that over 700 bacterial species colonize the human oral cavity. Some of these bacteria are associated with periodontal disease and dental caries, and some gain entrance to the circulation and are associated with systemic disease. Objectives: The purpose of this study was to identify oral bacteria in the blood of patients undergoing either a single tooth extraction, with or without antibiotic prophylaxis, or tooth brushing. Methods: Blood samples were taken at timed intervals before, during and following these two procedures and cultured in BACTEC media. Positive cultures were sub-cultured on differential media for isolation of both aerobic and anaerobic bacteria. Bacterial identification was based on sequence analysis of 16S rRNA genes. Genomic DNA was isolated and 16S rRNA genes were amplified by PCR. The sequences of the amplified genes were determined and compared with known sequences. Results: In the analysis of 410 isolates from 149 subjects, 119 different bacterial species belonging to 33 different genera were recovered including many known species of Streptococcus, Peptostreptococcus, Neisseria, and Prevotella. Species not often detected in the oral cavity were also isolated including Haemophilus aphrophilus, Solobacterium moorei, Shuttleworthia satelles and Acinetobacter sp. Of interest, 48 of the isolates were representing 24 novel species of Prevotella, Fusobacterium, Streptococcus, Actinomyces, Capnocytophaga and Veillonella. Conclusions: By using conventional culture techniques and 16S sequence analysis, a diverse bacterial population including novel species can be isolated from bacteremia following routine or invasive dental procedures. This work was supported by NIDCR grant R01-DE13559-01 A2.