Electronic Thesis and Dissertation Repository

Thesis Format

Integrated Article

Degree

Master of Science

Program

Surgery

Supervisor

Vasarhelyi, Edward M.

2nd Supervisor

Heinrichs, David E.

Co-Supervisor

Abstract

Staphylococcus aureus is a major cause of prosthetic joint infection (PJI) in which it forms adherent biofilms, thick aggregates of extracellular polymeric substances (EPS) produced by the bacteria. Biofilm associated infections are difficult to treat as they have increased resistance to various antimicrobial agents, which means infected implants often require multiple procedures and prolonged antibiotic therapy. However, a new and emerging method of treatment of PJI is non-contact induction heating (NCIH) of metal implants. We sought to investigate the feasibility and effectiveness of NCIH along with synergistic effects of antibiotics (Vancomycin) in reducing bacterial load within surface associated biofilms in vitro on stainless steel and titanium washers.

Our preliminary results support the hypothesis that NCIH of metal implants is effective in reducing bacterial load of S. aureus within a biofilm in vitro. In our study, the synergistical use of the dual treatment strategy (heat and antibiotics) resulted in a ~1000-fold total decrease in CFUs/ml (~3 log reduction). This suggests the potential synergistic effect between the heat and antibiotic treatment against biofilms. These results can be further explored as a new treatment modality for PJI and infections of orthopedic implants. Future work in this study will investigate if NCIH can be used synergistically with antibiotics to more effectively eliminate biofilm associated infections

Summary for Lay Audience

One of the most challenging complications after total joint replacement surgery is periprosthetic joint infections (PJI). Staphylococcus aureus is the bacteria responsible for the majority of these infections. One of the reasons that these infections are challenging to treat either with antibiotics or surgically with the present standard of care practices is that the residing bacteria form a “slime” like layer, called biofilms on the surfaces of the implants and the adjacent periprosthetic tissue. Biofilm associated infections are difficult to treat as they have increased resistance to various antimicrobial agents, which means infected implants often require multiple surgical procedures and prolonged antibiotic therapy. However, a new and emerging method of treatment of PJI is non-contact induction heating (NCIH) of metal implants. We sought to investigate the feasibility and effectiveness of NCIH of metal implants along with antibiotics in reducing bacterial load within surface associated biofilms in vitro. These preliminary results support the hypothesis that NCIH of metal implants is effective in reducing bacterial load of S. aureus within a biofilm in vitro. These results can be further explored as a new treatment modality for PJI and infections of orthopedic implants. Future work in this study will investigate if NCIH can be used synergistically with antibiotics to more effectively eliminate biofilm associated infections completely.

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