Orthopedic & Muscular System: Current Research
Open Access
ISSN: 2161-0533
+44-77-2385-9429
ISSN: 2161-0533
+44-77-2385-9429
Lloyd S Miller
Johns Hopkins University, USA
Scientific Tracks Abstracts: Orthop Muscular Syst
Infection is a devastating complication following orthopaedic surgical procedures. Bacteria form bio-films on the implanted materials, creating chronic infection and inflammation that leads to periprosthetic osteolysis, implant loosening and failure. These infections are challenging to diagnose and treatment is difficult and typically requires re-operations, prolonged systemic antibiotic courses, extended disability and rehabilitation. To study these infections, we developed a mouse model of an orthopaedic implant infectionin which a bioluminescent strain of Staphylococcus aureus was inoculated into a post-surgical knee joint of LysEGFP mice (expressing fluorescent neutrophils) that contained a titanium Kirschner-wire extending from the femur. In vivo bioluminescence and fluorescence imaging was used to noninvasively quantify the bacterial burden and neutrophil recruitment, respectively. We found that bioluminescent bacteria persisted for the 48 day experiment whereas EGFP-neutrophil signals decreased within the first 14-21 days. Using �¼CT imaging, the outer bone volume of the femur doubled, which was associated with low-density signals and bone loss, consistent with peri-implant osteolysis. This model was used to evaluate optimal antibiotic combinations to treat an existing infection as well as the novel antimicrobial implant coatings. Finally, as a new diagnostic approach, near-infrared fluorescent probes were used in combination with advanced techniques of photoacoustic imaging. This imaging modality has the potential for clinical translation since photo acoustic signals can be detected several centimeters into tissue. Taken together, bioluminescence, fluorescence, �¼CT and photoacoustic imaging represent valuable noninvasive techniques to study the pathogenesis of orthopaedic implant infections and to evaluate novel therapeutic and diagnostic strategies.
Lloyd S Miller completed his MD and PhD degrees from SUNY-Downstate Medical Center and Clinical Residency & Post-doctoral fellowship training at UCLA School of Medicine. He currently is an Associate Professor in the Johns Hopkins Departments of Dermatology, Medicine (Division of Infectious Diseases) and Orthopaedic Surgery. He has published over 30 peer-reviewed manuscripts, including high impact publications in Immunity and Journal of Clinical Investigation. For more than 10 years, he has been a pioneer in utilizing in vivo whole animal optical (bioluminescence and fluorescence imaging), μCT and photoacoustic imaging to study infectious diseases, including orthopaedic implant infections.
Email: lloydmiller@jhmi.edu