Antibiotic susceptibility of bacteria detected from the root canal exudate of persistent apical periodontitis.

Intracanal exudates in persistent endodontic cases were sampled for detecting bacteria using a preculture method, and the antibiotic susceptibility of the bacteria identified was examined. Twelve species were recovered from 15 cases. The species most commonly detected were alpha-Streptococcus and Enterococcus. The results of the antibiotic susceptibility tests revealed that Enterococcus was highly resistant to antibiotics tested, especially to cephalosporin products. Enterococcus is known as one of the bacteria that show multidrug resistance. In cases of prolonged endodontic treatment, a specific antibiotic prescription would play an important role for efficient treatment. Collecting data about antibiotic susceptibility could be helpful. Identification, however, take approximately 2 wk and a further study to develop the method that rapidly informs us about the antibiotic susceptibility that might be needed.