Biofilm Lysine Content May Identify Refractory Chronic Periodontitis

Objectives: The biological cause of poor response to therapy for chronic periodontitis (CP) is unknown. Antibiotic therapy improves poor response (PR) but not good response (GR) (JCP 2004;31(10):869-877), resulting in a greater use of antibiotics for CP therapy. Gingival crevicular fluid contains lysine and other nutrients which keep the epithelial attachment dentally attached but also promote biofilm development. Eikenella corrodens is increased in PR biofilm, and antibodies to lysine decarboxylase (LDC) in PR serum. We compared the lysine content and LDC activity of biofilm from selected PR and GR participants.
Methods: Biofilm lysine and cadaverine contents were measured and the mol fraction that was cadaverine indicated LDC activity (JOP 2012;83(8):1048-1056). Clinical measurements were obtained pre-therapy (baseline) and quarterly for a year from CP participants (9 GR and 8 PR), and also in 6 healthy controls (H). Therapy was scaling and root-planing with Widman flap surgery and oral hygiene instruction for CP participants, but only propylaxis for H. Attachment level (AL) decreased in GR relative to baseline within a year, but increased in PR. Therapy was repeated for PR, adding amoxicillin and metronidazole (respectively 500 and 250 mg t.i.d) for the first 2 weeks. AL change from baseline, biofilm lysine content and LDC activity were obtained after the original or restarted year.
Results: Biofilm lysine contents in PR were 0.07±0.03 μmol/g, but 0.20±0.09 in G and H (Kruskal-Wallis p< 0.01) and similar to H in the JOP study. CF was essentially identical in all groups. It was negatively associated with AL change in GR (Spearman R²=0.49, p<0.01), but positively in PR and H (Spearman R²=0.39; p<0.001).
Conclusions: Biofilm lysine content and the relationship of CF to therapeutic response differ between PR and GR. A low biofilm lysine content and high CF may signal a poor response to therapy and specify which CP patients most require antibiotic therapy.