A sticky bacterium versus antiadhesive surfaces: The adhesion preference of bacteria expressing trimeric autotransporter adhesin

The COVID-19 pandemic caused by a virus has been posing a global threat to humanity and human society. It reminded us of the horror of infectious diseases. Pathogenic bacteria also cause infectious disease, but bacteria are not as much of a threat as viruses because antibiotics are effective against them. This is changing, however, with the emergence of antibiotic-resistant bacteria. The global expansion of multidrug-resistant bacteria has become a clinical problem, and the threat of bacterial infection would come back in the near future. The overuse of antibiotics amplifies the opportunity for resistant bacteria to emerge and spread. The increased antibiotic use during this COVID-19 pandemic could also increase the threat of resistant bacteria. As an alternative to antibiotics, antibiofouling surfaces have drawn intensive research interest and have been developed. Acinetobacter sp. Tol 5 exhibits high adhesiveness to various surfaces through AtaA, a member of the trimeric autotransporter adhesin (TAA) family. We examined the adhesion of Tol 5 and other bacteria expressing different TAAs to antiadhesive surfaces. The results highlighted Tol 5’s stickiness through AtaA, which enables cells to adhere even to antiadhesive materials including polytetrafluoroethylene with a low surface free energy, a hydrophilic polymer brush exerting steric hindrance, and mica with an ultrasmooth surface. Tol 5 cells also adhered to a zwitterionic 2-methacryloyloxyethyl-phosphorylcholine-polymer-coated surface but were exfoliated by a weak shear stress, suggesting that exchangeable bound water molecules contribute to AtaA’s interaction with materials.