A possible new protection against biofilm formation, polymers found in mucus, have been discovered by a team of researchers from MIT.
Biofilms are slimy sheets of bacterial buildup that create a serious danger in medical and industrial environments. Once rooted, biofilms are extremely hard to get rid of, and much research has contributed to determining how to prevent and eliminate these harmful agents.
The team of biological engineers, whose work was published in Current Biology, discovered these polymers, called mucins, are able to catch bacteria and prevent them from sticking together on a surface, making them harmless.
Katharina Ribbeck, the Eugene Bell Career Development Assistant Professor of Biological Engineering and senior author of the paper says:
“Mucus is a material that has developed over millions of years of evolution to manage our interactions with the microbial world. I’m sure we can find inspiration from it for new strategies to help prevent infections and bacterial colonization.”
Mucin coverings could aid in preventing biofilm formation on medical devices and may find implementations in personal hygiene, such as combining them into products like toothpaste and mouthwash, which could boost the body’s own defenses, specifically in people whose own mucus has been used up.
Mucus runs along the wet surfaces of the body, areas like the respiratory and digestive tracts. “The textbook view of mucus is that it forms a barrier to infection, but it’s not at all clear how it does so,” Ribbeck says.
To answer this question, Ribbeck and her team examined the behavior of Pseudomonas aeruginosa bacteria in a growth method that has soluble purified mucins, long proteins complete with several fastened sugar molecules.
In order for bacteria to travel through the mucus layer and infect the tissues below, they need to create groups that can stick to the surface of the tissue. Immune cells are specialized to fight single bacterial cells, therefore, clusters of bacteria are harder for the immune system to eliminate.
“In general, you want to have bacteria around, you just don’t want them to team up. You want to them to be mixed with many other bacteria that are good for you. You don’t want a single species to take over, because then they may overgrow the system.”
In the current study, investigators found that mucins inhibit bacterial clump formation by not allowing them to stick, which is crucial for them to group together. When bacteria can move, they finish in a gooey mix and do less damage.
Ribbeck says, “The mucins have the ability to suppress virulence by keeping the cells separate. It’s like keeping your kids in separate rooms, so they will stay out of trouble.”
Sometimes, bacteria can breach this defense system and create infections. This can be sped up by a decrease in mucus due to dehydration, chemotherapy, and aging, or in mucus-clogged lungs of cystic fibrosis patients.
The main positive effect of using mucins as antimicrobial coverings, is that the substance demobilizes pathogenic bacteria without terminating them.
With that being said, it is less likely that bacteria could develop resistance to mucins, as they do to antibiotic medications. The advantageous bacteria that live on mucus membranes would also survive.
Ribbeck says, “This is a nice mechanism where you just suppress the virulence traits without killing the bacteria. It’s nature’s way of managing microbial behavioral in a way that could be useful to take advantage of.”
Ribbeck and her team are now looking into how mucins block bacteria from being mobile, as well as how they inhibit infection by non moving bacteria. She is also studying mucin interactions with other pathogenic organisms, like yeasts.
Written by Kelly Fitzgerald