Development of a biofilm model on plastic films

Abstract

Implantation of medical devices into patients is an essential component of modern medical care; however these devices significantly increase the risk of infection. Biofilms are the major contributing factor to implanted device-related infections. Microorganisms, especially bacteria, grow on the outer and/or inner surface of the foreign body to establish a biofilm. Biofilm associated bacteria exhibit greater tolerance to antimicrobial treatments. This poses a significant health burden, particularly for hospitalised patients with existing health problems and resolution of the infection consumes valuable medical resources. The considerable burden of biofilm-based implanted medical device-related infections has established a necessity to investigate prevention strategies. Preclusion of biofilm formation could circumvent these infections and the related problems, and involves impregnating implanted devices with an antimicrobial material. Work has been undertaken to establish a model of biofilm formation on implanted medical devices, utilising bioluminescent bacteria to test the efficacy of potential biocontamination-resistant surfaces in the form of plastic films. The degree of light detected from plastic films inoculated with lux tagged Escherichia coli 25922 correlated with bacterial growth. Plastic films inoculated with E. coli 25922 lux were implanted subcutaneously via incision along the dorsal midline into seven week old female CD1 mice and the bioluminescent signal was monitored in vivo using biophotonic imaging (BPI) techniques. Detection of bacterially-derived bioluminescence enables rapid, real-time observation of bacterial load circumventing the requirement to destroy an in vitro sample or to cull an experimental animal to enumerate the bacteria, reducing the number of animals required, workload and biological variability.