Engineering Approaches for the Detection and Control of Orthopaedic Biofilm Infections

Abstract

Artificial joints are subject to chronic infections associated with bacterial biofilms, which only can be eradicated by the traumatic removal of the implant followed by sustained intravenous antibiotic therapy. We have adopted an engineering approach to develop electrical-current-based approaches to bacterial eradication and microelectromechanical systems that could be embedded within the implanted joint to detect the presence of bacteria and to provide in situ treatment of the infection before a biofilm can form. In the former case we will examine the combined bactericidal effects of direct and indirect electrical fields in combination with antibiotic therapy. In the latter case, bacterial detection will occur by developing a microelectromechanical-systems-based biosensor that can "eavesdrop" on bacterial quorum-sensing-based communication systems. Treatment will be effected by the release of a cocktail of pharmaceutical reagents contained within integral reservoirs associated with the implant, including a molecular jamming signal that competitively binds to the bacteria's quorum sensing receptors (which will "blind" the bacteria, preventing the production of toxins) and multiple high dose antibiotics to eradicate the planktonic bacteria. This approach is designed to take advantage of the relatively high susceptibility to antibiotics that planktonic bacteria display compared with biofilm envirovars. Here we report the development of a generic microelectromechanical systems biosensor that measures changes in internal viscosity in a base fluid triggered by a change in the external environment.

Bases moleculares de la infección asociada a implantes ortopédicos

“…Se ha calculado que la tasa de infección asociada a material ortopédico después de una bacteriemia de S. aureus es alta, con un rango entre 30 y 40% 27 . Luego de "la carrera hacia la superficie", las bacterias estafilocóccicas establecen infecciones crónicas gracias a su capacidad de crecer en forma de biopelículas 6 . Las biopelículas son complejas comunidades de grupos de microrganismos auto-secretantes de una matriz de polisacáridos.…”

“…La frecuencia de infección asociada a implante ortopédico es relativamente baja, estimada en un rango entre 0,5 y 5% para reemplazos articulares (menos de 1-2% en instituciones con cirujanos altamente experimentados). Sin embargo, posee consecuencias devastadoras, determinando el retiro del implante y su sustitución en la mayoría de las veces, exponiendo al paciente a altos riesgos de recidiva infecciosa 1,5,6 . Es más, la infección de implantes ortopédicos resulta en una seguridad y longevidad alterada del mismo 7 .…”

Contaminação do ar em salas cirúrgicas durante cirurgias de artroplastias total de quadril e joelho, hemiartroplastias e osteossínteses no centro cirúrgico de um hospital Brasileiro

“…Os principais microrganismos presentes no ar de salas cirúrgicas incluem os Micrococcus sp e Staphylococcus sp, reflexo da sua presença na microbiota humana 3,4 . Em salas cirúrgicas com sistema dotado de filtros absolutos, com 99,9% de eficiência, estes microrganismos não são encontrados 8 .…”

“…Estes microrganismos formam biofilme nas superfícies de próteses e implantes, possibilitando uma maior resistência aos antibióticos 4 .…”

Influence of biomaterials on scintigraphic diagnosis of periprosthetic infections. Ceftizoxime-99m technetium model

“…Bacterial adherence and formation of biofilms on the surface of the prostheses are key steps in the pathogenesis of these infections, making them resistant to the host defense mechanisms and the action of antimicrobial agents [6][7][8] . In addition to treatment resistance, the diagnosis of periprosthetic infections also becomes difficult.…”