By greatly reducing the effects of antibiotics, the formation of organized communities of bacterial cells, known as biofilms, can be fatal especially post-op or during urinary tract infections. This Yale team has just deciphered the process of formation of these biofilms. With this new understanding of these highly effective forms of antibiotic resistance, the team is also suggesting new ways to stop them.
Biofilms form when bacterial cells clump together and develop structures that bind them into a sticky substance, the researchers say. This sticky membrane can protect cells from the outside world and allow them to form complex quasi-organisms. Moreover, biofilms are everywhere, in shower cubicles or on the surface of bodies of water. However, when they invade human cells or form on sutures and catheters used in surgery, they form an indestructible, antibiotic-resistant mass. Thousands of deaths are attributable to surgical site infections (SSI), healthcare-associated infections (HAI) and biofilm-related urinary tract infections.
Biofilms are thus a major medical problem because they make bacterial infections extremely difficult to treat, recalls lead author Andre Levchenko. But if the fight against biofilms is so difficult, it is also because we do not fully understand how bacterial cells make the transition between individual behavior and participation in a collective structure. The Yale team, in collaboration with colleagues from the University of California San Diego, decipher here the key mechanism of biofilm formation, which then allows them to reproduce, under control and under observation, the process.
Uncontrolled growth and self-generated stress: using microfluidic devices and gels containing uropathogenic cells of E. Coli, such as the cause of urinary tract infections, scientists observe that the bacterial colonies grow to the point of being compressed by the walls of the chamber of the device. This self-generated stress seems to be the very trigger for the formation of the biofilm: “ the cells are then subjected to biological stress and this stress seems to come from this mechanical interaction with the environment ”.
A reproducible model to study biofilm: Researchers can now explore the formation of biofilms in countless environments or even more simply, use the devices presented in this study to produce biofilms quickly, accurately and in large numbers, in a simple way , inexpensive and reproducible. This new understanding of the mechanism of biofilm formation will obviously considerably facilitate research and testing of new antimicrobials capable of piercing the protective layer of biofilms and then breaking them down.
“ Having a model like this is essential for conducting drug trials. We can now grow biofilms in specific shapes and locations in totally predictable ways .”
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