Identification of microbial biofilms in osteonecrosis of the jaws secondary to bisphosphonate therapy

Biofilm theory has emerged to explain the etiology of the chronic infections that have come to constitute between 65% to 80% of the microbial diseases treated by physicians in the developed world. The purpose of this article is to report for the first time the observation of multispecies microbial biofilms on affected bone in patients with osteonecrosis of the jaws (ONJ) secondary to bisphosphonate therapy.

A program has been established at the University of Southern California to monitor and evaluate patients with ONJ as a multidisciplinary collaboration between the School of Dentistry, Center for Biofilms, Center for Craniofacial Molecular Biology and the Keck School of Medicine. From this cohort, 4 patients with active ONJ who were scheduled for necessary treatment in the form of sequestrectomy gave informed consent for this study. Bone samples were evaluated using conventional histopathologic techniques and scanning electron microscopy, a technique applicable to biofilm characterization.

Bone specimens from affected sites in all patients showed large areas occluded with biofilms comprising mainly bacteria, and occasionally yeast, embedded in extracellular polymeric substance. The number of bacterial morphotypes in the biofilms ranged from 2 to 15, and they included species from the genus Fusobacterium, bacillus, actinomyces, staphylococcus, streptococcus, Selenomonas, and 3 different types of treponemes. The yeast identified was consistent with Candida species. Co-aggregation was observed between different species within the biofilms.

These findings have important clinical and therapeutic implications and may suggest a role for microbial biofilms in the disease process of ONJ.