Effect of anaerobic bacteria in apical periodontitis on intracellular signal transduction of the host

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Analysis of root canal exudate is important to clarify the mechanism for persistent apical periodontitis. This study compared the ability of bacterial detection from the intracanal exudate by two methods. One is a conventional method, i.e.the samples were transported into anaerobic chambers immediately after sampling and then moved to an outside laboratory for bacterial identification. Another is a pre-culture method, i.e.the samples were inoculated into semi-solid medium immediately after sampling, incubated for 24 hours anaerobically, and moved to the laboratory. The pre-culture method detected bacteria in 18 cases of 22 persistent cases, while the conventional method detected bacteria in 6 cases from 22 cases. The pre-culture method showed the significantly higher frequency of bacterial detection. Gram positive cocci like Enterococcus were detected in many cases. These results suggested that the pre-culture method could be helpful for detecting the intracanal bacteria and contribute … More efficient endodontic treatment using antibiotics.Intracellular reaction might be involved when the bacteria invaded into the host. We compared the restriction profiles of the DNA extracted from five strains of Enterococcus isolated from clinical cases and investigated the effect of them on tyrosine phosphorylation in HeLa cell because it plays an important role in signal transduction. DNA patterns were different in all strains isolated and it revealed that the origin of them were different. However, there were some stimulation in clinical symptoms and X-ray appearance. Therefore, it was thought that the bacteria might have caused same reactions in the host cell even if the bacteria strains were different. The stimulation by Enterococcus did not alter the tyrosine phosphorylation. This suggested that the direct bacterial stimulation might not affect the signal transduction. However, intracellular and intercellular reactions have complex networks and further studies will be needed to analyze the relationships between the endopathogenic bacteria and the host. Less