|Clawson, Michael - Mike|
Submitted to: Journal of Clinical Microbiology
Publication Type: Peer reviewed journal
Publication Acceptance Date: 6/10/2002
Publication Date: 9/1/2002
Citation: FOUAD, A.F., BARRY, J., CAIMANO, M., CLAWSON, M.L., ZHU, Q., CARVER, R., HAZLETT, K., RADOLF, J.D. PCR-BASED IDENTIFICATION OF BACTERIA ASSOCIATED WITH ENDODONTIC INFECTIONS. JOURNAL OF CLINICAL MICROBIOLOGY. 2002. v. 40. p. 3223-3231. Interpretive Summary: This study addresses the detection of microbial pathogens associated with dental decay in humans. Unlike previous studies that detected pathogens by culturing techniques, we used PCR to detect bacterial species. We targeted organisms suspected of facilitating the persistence or spread of periapical lesions despite seemingly adequate endodontic treatment. Since there is an inherent bias in detecting organisms by traditional culturing techniques, PCR is a considerable improvement in detection techniques. Specific primers targeting the 16S rRNA gene for nine bacterial species (or the tuf gene for Enterococcus species) were used. We found a positive or significant association between several bacterial species and preoperative symptoms. Additionally, we found a positive association with two pathogens in patients afflicted with diabetes mellitus. We further identified a novel microbe associated with endodontic infection by 16S rRNA sequence generated with universal primers. Thus, PCR can be used to detect both known and unknown pathogens associated with endodontic infections.
Technical Abstract: PCR primers, that target the bacterial 16S rRNA genes (or the tuf gene for Enterococcus genus), were used to identify 10 putative bacterial pathogens in root canals with necrotic pulp. In addition, the associations of these microorganisms with symptoms and a history of diabetes mellitus were investigated. Microbial samples from the root canals of 24 teeth with necrotic pulp were included in the study. PCR with universal bacterial primers identified bacterial DNA in 22 specimens; the remaining two were from intact teeth that were traumatized 6 months prior to treatment. PCR with specific primers showed that preoperative symptoms were significantly associated with the presence of Streptococcus spp. (Chi-square, p < 0.001), and positively associated with Fusobacterium nucleatum and Porphyromonas gingivalis (odds ratio >2). Diabetes mellitus was positively associated with P. gingivalis and P. endodontalis (odds ratio >2). Cloning and sequencing of the universal PCR product in one specimen revealed the presence of an organism related to the genus Olsenella, which has not been previously described in endodontic infections.