Biofilm-REsponsive Adjuvant as novel THerapeutic approach

The aim of the Biofilm-REsponsive Adjuvant as novel THerapeutic approach (BREATH) project is to help people affected by mucoviscidosis by improving the treatment of lung infection. Mucoviscidosis (also called cystic fibrosis, CF) is a rare disease originating from a genetic mutation, which affects 1 child in every 2000 births, corresponding to around 40 000 people in Europe. Patients with CF- disease will suffer from impaired respiratory function with recurrent lung infection. Cystic fibrosis can still not be cured and the life of patients is shortened due to the accumulated damage of their lung associated with poor respiratory function. Because of the presence of a sticky mucous secreted in the lung of CF-patients, bacteria (with Pseudomonas aeruginosa being predominant) will develop rapidly and form a biofilm. The specificity of this biofilm relies in this composition, with high amount of alginate. Alginate is a polysaccharide that obstructs the airway of CF-patient and protects the microorganisms from therapies. To prevent further spreading of infection, medical treatment includes prolonged course of antibiotics, given orally, intravenously or by inhalation. Unfortunately, those antibiotic regimens must be repeated, as bacteria embedded in an alginate-rich biofilm are impossible to eradicate. As very few antibiotics have been discovered since several decades, the scientific community must focus its effort in optimising the efficacy of the ones currently available, which is the goal of the BREATH project. The final aim of BREATH project is to screen and identify small molecules, administrated as adjuvant to antibiotics, that will enhance the efficacy of the drugs and improve treatment of CF-lung infection. A key point of the BREATH project is to develop in vitro a simplified 3D model of biofilm with features and characteristics relevant to mimic CF-lung condition. This model will be produced using 3D Bioprinting, based on alginate and other import extracellular polymeric substances (EPS). At a later stage, we will then incorporate the microorganisms into this model and use it as an in vitro tool to rapidly test antibiotics and to select new adjuvants. The selected adjuvants must interact with alginate/EPS and increase its permeability to the penetration of antibiotics. To reach the goal of BREATH, this multidisciplinary project gathers scientific expertise in biomaterials, chemistry, microbiology, biointerface and pharmaceutical sciences, from TU Wien (Dr. Guillaume O and Prof. Ovsianikov A., Institute of Materials Science and Technology, 3D Printing and Biofabrication Group) in collaboration with the BOKU (Prof. Reimhult E., the Institute for Biologically Inspired Materials). If successful, our strategy could be employed to treat not only CF-lung infection but also to develop novel drug delivery systems that could potentially optimize the treatment of other biofilm and chronic infections.

Chronic bacterial infections are difficult to eradicate because bacteria can form biofilms - protective communities embedded in a self-produced matrix that shields them from antibiotics and the immune system. This is a major challenge in cystic fibrosis (CF), an incurable disease affecting tens of thousands of people worldwide, where persistent Pseudomonas aeruginosa (PA) infections progressively damage the lungs. The BREATH project combined expertise in biomaterials, microbiology and advanced imaging to understand how antibiotics interact with biofilms and why treatments often fail. Rather than acting as passive barriers, biofilms can respond dynamically to antibiotics, potentially changing their structure and reducing drug effectiveness. Understanding these processes is essential for developing improved therapeutic strategies. Researchers at TU Wien developed innovative alginate-based biofilm mimics that reproduce key features of the extracellular matrix surrounding bacteria in CF lungs. By controlling alginate acetylation to resemble bacterial biofilms, they created realistic 3D models for studying how proteins and antibiotics interact with the matrix. These studies showed that biofilm chemistry strongly influences antibiotic binding and transport. At BOKU, complementary work focused on PA in biofilms and printed biofilm models from TU Wien. Using diffusion and viability assays, confocal microscopy, and cryo-scanning electron microscopy, the team quantified antibiotic transport and revealed previously unknown structural features of the biofilm matrix. Mucoid PA biofilms were shown to be stratified, organized communities of separated cells rather than dense microcolonies. While the matrix components of native biofilms could hinder some antibiotics, it was shown that the main structural components, alginate and DNA, were not responsible for this and that the remarkable antibiotic tolerance in biofilms was neither explained by bacterial resistance mechanisms nor fully by the chemical and physical obstruction by the bulk extracellular matrix, suggesting the need for new directions in cystic fibrosis anti-biofilm therapies. Together, the partners established reproducible 3D biofilm models that closely mimic conditions in CF lungs and provide a powerful platform for testing antibiotics under clinically relevant conditions. These models enable systematic investigation of how biofilm composition influences drug diffusion and bacterial persistence, supporting the development of more effective therapies and biofilm-targeting treatment strategies. By combining materials science and microbiology, BREATH generated new knowledge that could improve the treatment of chronic biofilm-associated infections and ultimately benefit patients with cystic fibrosis and other persistent bacterial diseases.