Anti-Biofilm Activity Assessment

In vitro characterization and in vivo efficacy evaluation of selected compounds against relevant biofilm-producing Gram-positive and Gram-negative pathogens (WP3)

Dr. Antonio Felici
Aptuit (Verona) S.r.L

Bacteria are no longer considered to be the archetypal single-celled organisms. It is now known that they prefer life in communities, and that they readily attach to biotic or abiotic surfaces to form structures called biofilms [Greenberg. Nature. 424, 134 (2003)]. Indeed, most bacteria spend most of their time in the biofilm growth mode. Biofilms are commonly-associated with many chronic infections. By definition, chronic infections are not easily resolved through antibiotic intervention, and indeed, this feature may be directly related to biofilm formation. This is because biofilms are intrinsically >10-100 fold more resistant to antibiotics than planktonic cells. Consequently, there is an urgent need to develop strategies that reduce or even abolish biofilm formation. For example, the respiratory infections associated with many adult cystic fibrosis (CF) patients are a result of chronic infection by Pseudomonas aeruginosa. Our main aim is be to identify and characterize compounds that prevent biofilm formation, with particular attention paid to the role played by biofilms and biofilm blockers at the host-pathogen interface. By preventing biofilm formation through application of anti-biofilm agents, the cells should be “locked” in the antibiotic-susceptible planktonic growth mode, enabling resolution of the infection. Quorum sensing has been shown to have a major impact on biofilm formation, so quorum sensing blockers (such as N-acyl homoserine lactone analogues and PQS analogues [Storz et al. J Am Chem Soc. 134, 16143-6 (2012)] will be a major (but not exclusive) focus of our analysis. We will screen compounds for anti-biofilm activity in an optimized high-throughput 96-well microtiter plate-based procedure in vitro. Representative strains of the Gram-negative ESKAPE pathogens will be tested. Following mammalian cytotoxicity determination of hits, we will then develop one or more animal models of bacterial infection for the evaluation of in vivo efficacy of key compounds. This will be accompanied by additional, detailed characterization of their possible MoA, off-target effects, etc. 

Objectives: In vitro characterization of new chemical entities designed and selected during the project effort. Set up, validation and application of tailored animal models of bacterial infections for assessing the in vivo efficacy of selected compounds against biofilm producing bacteria and to develop PK/PD models for translation to clinic.

Expected Results: Identification of novel, potent, and selective antibacterial compounds able to inhibit biofilm formation and release of virulence factors during infection.

This project has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Sklodowska Curie grant agreement No  642620
European Union