Novel Insights Into the Struggle Against Biofilm: The <i>Psy</i> <scp>Omp38</scp> Protein From the Antarctic Marine Bacterium <i>Psychrobacter</i> sp. <scp>TAE2020</scp>

Antibiofilm molecules can enhance the effectiveness of antibiotics and prevent biofilm formation. Antarctic marine bacteria have been found to secrete antibiofilm molecules, likely as part of a strategy for competitive survival. The protein-polysaccharide complex CATASAN, produced by the Antarctic bacterium Psychrobacter sp. TAE2020, has been shown to interfere with all stages of Staphylococcus epidermidis biofilm development. This study investigates the contribution of PsyOmp38, the protein component of CATASAN, to the complex's antibiofilm activity. The protein was heterologously expressed in Escherichia coli, purified, and characterised, revealing its ability to inhibit Staphylococcus epidermidis adhesion to surfaces, interfere with biofilm formation, and disrupt mature biofilms. Following biocompatibility assessment, PsyOmp38 was tested in combination with vancomycin as a potential treatment for established infections, revealing a reduction in the minimum biofilm eradication concentration (MBEC) of vancomycin. The potential of PsyOmp38 for material functionalisation was also explored. The protein was deposited onto silicone-based surfaces, and the coated materials were tested in a continuous-flow system that simulated real-life conditions. Additionally, the three-dimensional structure of PsyOmp38 was predicted and compared with homologous proteins. The structural analysis not only revealed the unique features of PsyOmp38 but also provided important insights into the molecular mechanisms underlying its antibiofilm activity.