New Insights into Biofilm Formation and Dispersal

Biofilms, the oldest form of multicellularity on Earth, are bacterial communities encased in a slimy matrix. These structures attach firmly to a wide range of surfaces, including living tissue, and exhibit strong resistance to antibiotics.

Although it is widely believed that the matrix, a complex shared home made up of extracellular polymeric substances, holds biofilm cells together, little is known about the biochemical dynamics underlying these interactions.

A group of Yale researchers recently conducted a study to learn more about how these bacteria assemble, identify one another, escape their sticky matrix, procreate, and spread. According to researchers, a deeper comprehension of the molecular and biophysical interactions within biofilm communities may result in novel approaches to treating biofilm-related infections, which are challenging to treat with conventional antibiotics.

Under the direction of Jing Yan, Assistant Professor of Molecular, Cellular, and Developmental Biology in Yale's Faculty of Arts and Sciences, the research team used genetics, microscopy, simulations, and biochemical analyses to try to understand how the cholera-causing bacterium Vibrio cholerae creates biofilms, escapes, and establishes new communities.

The study was published in the journal Nature Communications.

Researchers claim that exopolysaccharides (EPS), or lengthy sugar chains, make up the majority of the matrix that surrounds the bacterial colony. However, the team discovered that, in contrast to popular belief, the purified EPS is not sticky to the cells. Instead, they discovered that it repels cells that do not make EPS.

They discovered that bacteria that are actively producing EPS are drawn to one another and keep out the lazy ones that are attempting to enter the cell matrix but are not paying for the production of EPS.

It is like a membership card. If you pay the price to make EPS, you are welcomed into the club."

Jing Yan, Assistant Professor, Yale University

Yan is also a member of the Quantitative Biology Institute at Yale.

However, the research team discovered that bacteria alter their surfaces as the biofilm ages, changing the interactions between EPS-producing cells and the matrix from attractive to repulsive. They claimed that this enables the bacteria to break free and establish new colonies.

This smart strategy helps the bacteria disperse as groups, ready to colonize new environments.”

Alexis Moreau, Postdoctoral Researcher and Study Lead Author, Yale University