Mechanical forces of biofilms could play role in infections

The overwhelming majority of bacteria on the planet are found in colonies termed “biofilms” that grow on the surface of anything they come in contact with. Scientists refer to these microbe-rich areas as “cities” since they are home to tens of thousands to millions of different kinds of bacteria. In reality, bacteria prefer to live in biofilms. These biofilms are formed by microorganisms adhering to a variety of surfaces, including the ocean bottom, internal organs, and teeth. There are a variety of pathogens that create biofilms in the lungs of people with cystic fibrosis, including the common bacterium Pseudomonas aeruginosa. The relationship between a biofilm and its host is generally considered to be biochemical in nature. A growing body of research suggests that the physical, mechanical interaction between these two agents may have an even greater impact on the host’s physiological state than previously thought. An EPFL research team headed by Alex Persat is attempting to address this issue. According to a study published in the journal eLife, the biofilms of two common pathogenic bacteria, Vibrio cholerae and P. aeruginosa, may distort soft materials like hydrogels significantly. Biofilms are formed when bacteria adhere to and multiply on a surface. A mass of dead cells, proteins, polysaccharides, and nucleic acids surrounds them as they try to find their way out. After mixing, the result is a gooey material known as the “EPS matrix” (EPS stands for “extracellular polymeric substances”).

In the EPS, when bacteria multiply, they stretch or compress the material, causing it to become stressed mechanically. Internal mechanical tension is created by the development of the biofilm and the elastic characteristics of the EPS matrix. Biofilms were grown on soft hydrogel surfaces, and pressures produced by the biofilms were evaluated in relation to varying EPS components. Thus, it was discovered that, like a carpet or a ruler, biofilms cause deformations by “buckling.” The extent of the deformations is determined by the stiffness of the “host” material and the EPS’s chemical makeup. V. cholerae biofilms, according to the study, are capable of generating enough mechanical stress to distort and destroy delicate epithelial cell monolayers, such as those that line the surface of our lungs and intestines. To put it another way, the developing biofilms may mechanically harm their host’s physiology. In other words, biofilms have the potential to induce an infection mode known as “mechanical,” necessitating the development of novel treatment strategies.

Journal Reference : Alice Cont, Tamara Rossy, Zainebe Al-Mayyah, Alexandre Persat. Biofilms deform soft surfaces and disrupt epitheliaeLife, 2020; 9 DOI: 10.7554/eLife.56533

Categories: Clinical