Microbiological investigation of medication-related osteonecrosis of the jaw: preliminary results

Medication-related osteonecrosis of the jaw (MRONJ) is a well-recognized severe complication of bisphosphonate (BPs) treatment in patients with osteoporosis or metastatic cancer. Microbiological infection has been hypothesized as a contributing factor to bisphosphonate related osteonecrosis of the jaw (BRONJ). Despite infection being present in BRONJ patients, there is no clear data as to whether infection plays a role in the pathophysiology. Moreover, microbial cultures have not been helpful in directing therapy because specific pathogens have not been identified. The objective of this study was to determine the bacterial colonization of jawbone and identify the bacterial phylotypes associated with BRONJ. Twenty oncologic patients, aged 48-87 years (average age 70.65 ± 8.86 years) with BRONJ were enrolled in this study and underwent three different microbiological samplings. Overall, 60 samples were obtained from oral mucosa, necrotic bone fragments and fistula drainage. The same procedure was performed for the laboratory culture of all these specimens. No significant differences regarding either gram+ and gram– species (Chi-squared= 0.1642; p = 0.6854) or aerobes and anaerobes bacteria (Chi-squared= 3.084; p = 0.0791) were found. Compared to other sampling techniques, the oral swab allowed to obtain valuable microbial data in order to recognize pathogens responsible for the infection and to outline a focused antimicrobial therapy.