Biomaterial-associated infection: A perspective from the clinic

Abstract

Implant-associated infections are caused by microorganisms which adhere to the device and form biofilms. Medical devices are highly susceptible to bacterial and fungal infections. The minimal abscess-producing inoculum is >10,000-fold lower in the presence than in the absence of a foreign body. This is mainly due to a local granulocyte defect. Not only abiotic, but also biological (devitalized) implants are prone to infection. Among the clinically most important devices are prosthetic joints. These implants are at life-long risk for infection. During the first 2 years after implantation, the majority of the infections are exogenous; later, they are mainly caused by the hematogenous route. The treatment goal is complete eradication of infection, freedom of pain, and correct function of the joint. Reaching this goal requires rapid diagnosis and a rational treatment strategy including adequate surgery (debridement, one-stage or two-stage exchange) combined with prolonged antibiotic therapy. Surface adhering biofilms are highly resistant to host defense and antimicrobial agents. According to animal experiments and clinical studies, rifampin is more efficacious against surface adhering staphylococci than other agents. In view of the limited efficacy of treatment, novel preventive options are required such as implant coating or quorum sensing inhibitors.