Method: A review of cases with a clinical history of BON was determined by hand searching records submitted to a regional diagnostic oral microbiology laboratory over the last 3 years.
Results: Six specimens (four bone and two swabs) were received from six patients, with a history of either taking or had taken bisphosphonate medication, and had a clinical diagnosis of BON. Fourteen different organisms were isolated from the six specimens. The most common anaerobes isolated were Peptostreptococcus and Veillonella species. The most common facultative isolates were from the Streptococcus mitis group (S. oralis and S. parasanguis) and the Streptococcus anginosus group. One specimen contained a mixed growth of Actinomyces myerii. A large proportion of isolates were resistant to the first line antimicrobials of amoxicillin (74%) and clarithromycin (78%).
Conclusions: Our results, from this small cohort of patients, demonstrate that mixed infections comprising strict anaerobes and Streptococcus spp. are the predominant isolates from BON specimens. Of interest is the reduced antimicrobial susceptibility of these isolates which probably reflects the exposure of this group of patients to multiple courses of antimicrobial therapy. This data should be considered when proposing guidelines for prophylaxis and therapy of BON