Fusobacterium nucleatum in periodontal health and disease.

The pathogenesis of periodontitis involves the interplay of microbiota present in the subgingival plaque and the host responses. Inflammation and destruction of periodontal tissues are considered to result from the response of a susceptible host to a microbial biofilm containing gram-negative pathogens. Antimicrobial peptides are important contributors to maintaining the balance between health and disease in this complex environment.

Concentrations and in vivo antibacterial activity of spiramycin and metronidazole in patients with periodontitis treated with high-dose metronidazole and the spiramycin/metronidazole combination.

Objectives: Previous studies have shown that metronidazole, alone or in combination with spiramycin (250 mg/1 500 000 units, three times/day), is an effective treatment for active periodontitis, although the dose of metronidazole currently used (750 mg/day) could provide concentrations in gingival crevice fluid that are too low for the MICs of the involved pathogens. This study tested the in vivo antibacterial efficacy of the currently used metronidazole dose (as contained in the fixed spiramycin/metronidazole combination) in patients with an active periodontitis, and of a high dose (1500 mg/day) of metronidazole alone.

Methods: We measured the MICs of spiramycin and metronidazole for the recovered pathogens and the gingival crevice fluid antibiotic concentrations of both antibiotics, and attempted to correlate them with bacterial eradication.