In vitro Investigation of the Antimicrobial Effect of three Bisphosphonates against different Bacterial Strains

Publication date: Available online 31 August 2017
Source:Journal of Oral and Maxillofacial Surgery
Author(s): Michael A. Ermer, Simon C. Kottmann, Jörg-Elard Otten, Annette Wittmer, Philipp Poxleitner, Klaus Pelz
PurposeSince the first descriptions of medication-related osteonecrosis of the jaws (MRONJ) in 2003, the pathogenesis has remained unanswered. Recent histomorphometric studies have found several microorganisms like Actinomyces, Bacillus, Fusobacterium, Staphylococcus, Streptococcus, Selenomonas, Treponema and Candida albicans in necrotic bone. PCR studies confirmed occurrence of 48 genera recently.Only few studies deal with the antimicrobial effect of bisphosphonates (BPs). The influence of bacterial growth on the etiology stays unclear. The aim of this study was the in vitro investigation of the antimicrobial effect of three bisphosphonates against different bacterial strains.Material and MethodsMinimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of 48 strains from 40 species were determined in microdilution assays against pamidronic, ibandronic and zoledronic acid.ResultsGrowth of the gram-positive oral microbiota, which account for the majority of microorganisms in MRONJ, is affected for 2 out of 22 species. 6 out of 26 gram-negative species and 9 out of 13 anaerobes are inhibited. The MIC values were compared to BP bone concentrations described in literature. In total, 9 of 48 strains have MIC or MBC below the bone concentrations.ConclusionThe results of this study demonstrate that BPs have an inhibitory effect on selected bacterial species and may inhibit growth of some relevant pathogens in osteonecrosis. At the same time, the majority of species tested, are unaffected at concentration levels assumed in human jawbone. The clinical relevance of these in vitro data will better be clarified with reliable data on the BP concentrations in human jawbone. For the assessment of the interaction of oral bacteria and BPs, this study provides a first approach.



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