How bacteria use sticky patches to adhere to surfaces
Understanding how bacteria stick, the differences of adhesion within a population of bacteria, and its influence in biomedical applications.
Bacteria are very good at sticking to surfaces, where they can be a major source of infections. For example, they can contaminate medical devices, food packaging and drinking water systems, and there are ongoing efforts to design surfaces that prevent bacterial adhesion. A team of researchers from the School of Physics and Astronomy and School of Engineering used cutting-edge microscopy and image analysis techniques to probe the adhesion of rod-shaped Escherichia coli bacteria to glass surfaces. It appears that there are large differences between individual bacteria in how they stick to the surface that can be explained with a “patchy model”.
The researchers recorded movies of many bacterial cells on a glass surface. Using in-house developed software, they followed the positions and orientations of the cells and studied their dynamics. Some bacteria readily adhere to the surface while others never do. Even if they adhere, there can be differences between individual cells. Some cells attach to a surface for several hours, while others bind only weakly and detach rapidly.
The results can be explained with a model in which bacteria adhere with a limited number of adhesive patches on their body. Strong adherers can stick with multiple patches, while weakly adhering cells are bound with just a single patch, and non-adhering cells have no adhesive patches at all. Interestingly, all these differences are found within populations in which all cells should have the same genes. Apparently, individual cells express these genes differently, thus making the behaviour of each cell differ.
Apart from the academic relevance, the results of the study can be used to realise novel anti-adhesion surfaces. It seems the design of such materials should take into account that not all cells stick in the same way, and that adhesion takes place on specific spots on the bacteria.