Actinomyces israelii in radicular cysts: a molecular study

Objective To investigate whether the microscopic filamentous aggregates observed in radicular cysts are associated with the molecular identification of Actinomyces israelii . Moreover, to verify whether this bacterium can be detected in radicular cyst specimens not presenting aggregates. Study Design Microscopic colonies suggestive of Actinomyces were found in 8 out of 279 radicular cyst samples (case group). The case and control groups (n = 12; samples without filamentous colonies) were submitted to the semi-nested polymerase chain reaction to test the presence of A israelii. DNA sequencing was performed to validate polymerase chain reaction results. Results Two and 3 samples in the case and control groups, respectively, did not present a functional genomic DNA template and were excluded from the study. A israelii was identified in all samples of the case group and in 3 out of 9 samples of the control group. Conclusions Although A israelii is more commonly identified in radicular cysts presenting filamentous aggregates, it also appears to be detected in radicular cysts without this microscopic finding.