Dual Species Bacterial Challenge of a Biomimetic Nanostructured Surface

An ever-present risk of medical device associated infection has driven a significant body of research toward development of novel anti-infective materials. Surfaces bearing sharp nanostructures are an emerging technology to address this concern. The in vitro efficacy of antimicrobial nanostructures has previously been verified using single species cultures, but there remains a paucity of data to address the threat of infections containing more than one species. Polymicrobial infections are a concerning threat because they can complicate treatment, promote drug resistance, and harshen patient prognosis. In the present study, dual-species cultures are employed to challenge the mechano-bactericidal properties of nanostructured surfaces. Escherichia coli is used with either Staphylococcus aureus or Enterococcus faecalis due to their clinical relevance in implant associated infection. Despite the presence of two mixed species, a high rate of bactericidal activity is found. Interestingly, in the mixed culture containing Escherichia coli with Enterococcus faecalis, the nanostructured surface triggers a shift in species distribution to favor Enterococcus faecalis. Overall, this study highlights the potential for mechano-bactericidal surfaces to minimize the burden of infections containing more than one species. It also serves as an enticing foundation for further research into more complex biointerfacial interactions.