A bioluminescence-basedex vivoburn wound model for real-time assessment of novel antibacterial compounds

The silent pandemic of antibiotic resistance is thriving, prompting the urgent need for the development of new antibacterial drugs. However, within the preclinical pipeline, in vitro screening conditions can differ significantly from the final in vivo settings. To bridge the gap between in vitro and in vivo assays, we developed a pig skin-based bioluminescent ex vivo burn wound infection model, enabling real-time assessment of antibacterials in a longitudinal, non-destructive manner. We provide a proof-of-concept for A. baumannii NCTC13423, a multidrug-resistant clinical isolate, which was equipped with the luxCDABE operon as a reporter using a Tn7-based tagging system. This bioluminescence model provided a linear correlation between the number of bacteria and a broad dynamic range (10 4 to 10 9 CFU). This longitudinal model was subsequently validated using a fast-acting enzybiotic as an antibacterial. Since this model combines a realistic, clinically relevant yet strictly controlled environment with real-time measurement of bacterial burden, we put forward this ex vivo model as a valuable tool to assess the preclinical potential of novel antibacterial compounds. Summary statement Here, we demonstrate the potential of a bioluminescence-based ex vivo model for the longitudinal assessment of antibacterials. Moreover, we also provide a proof-of-concept with an engineered lysin.