(107a) Bad to the Bone: Biofilm and Surgical Infection

Infection remains the oldest and largest challenge in surgery. Knee and hip arthroplasty or total joint replacement provides an excellent illustration of this problem. Arthroplasty is one of the largest major surgical procedures in the world by volume and is an engineering marvel. It has been named one the greatest medical innovations of the twentieth century. Periprosthetic joint infection is the most common cause for total knee arthroplasty failure, and is a devastating surgical complication. Similar to other surgical site infections, morbidity and mortality is high. Staphylococcus aureusis the most common organism associated with surgical infections, including periprosthetic joint infection. These organisms can rapidly form a biofilm in the wound and on the implant. First-line treatment for surgical infection is irrigation, debridement, and treatment with long term antibiotics. Failure rate of irrigation and debridement is high. This high failure rate is a result of the high tolerance of biofilm to antibiotics. This tolerance is regulated by a number of different mechanisms. One of these includes bacterial persisters, a small subset of a bacteria population which are phenotypically tolerant to antibiotics. Persisters are clinically important because they are increased in biofilms, and play a role in the relapse of chronic infections. This is achieved, in part, through multiple toxin-antitoxin systems that induce a decreased metabolic state. A limited number of experimental methods to kill persisters have been discovered, and persister metabolism plays a vital role in each approach.