Industry Approach to Developing and Evaluating Antimicrobial Technologies-Multi-model Regime for Determining Antimicrobial Effectiveness

The evidence implicating microbial biofilms as a cause for wound chronicity is substantial and growing.^1-4 It is known that microorganisms in biofilms can withstand 100-1000 times higher antimicrobial concentrations than their planktonic counterparts, yet treatment decisions for wound care have been historically based on planktonic paradigms.^5-7 There are numerous biofilm models available for evaluating antibiofilm effectiveness but correlating in vitro performance data to clinical effectiveness is difficult due to the complexity of how biofilms exist and interact with their hosts.^6,8 Differences in model design and test conditions have led to conflicting laboratory data about efficacy of antimicrobial products in biofilms,⁹ so it is challenging for clinicians to predict which technologies may provide a clinical benefit. This challenge also affects the development and evaluation of new antimicrobial technologies. With the lack of a single reference method, we employed a regime of in vitro microbial biofilm models, both newly developed and adapted from others’ publications, to test antimicrobial performance of commercially available wound care products. Significant differences in effectiveness were observed between different antimicrobial wound care products in different biofilm models. After evaluating performance in in vitro models, the most effective antimicrobial products were evaluated in an in vivo biofilm wound model, which showed differences in effectiveness that were not observed in vitro. The data presented here suggest that no single microbial biofilm model can entirely recreate what is found in a chronic wound environment, so the best way to evaluate antimicrobial effectiveness is through performance testing in several different models with varied complexity.