When bacteria flock together and form a community, this is called a biofilm. Found all over the planet — from desert rocks to the surfaces of buildings — biofilms are an integral part of nature.
Biofilms are tricky beasts because they have a tendency to become resistant to all manner of efforts employed to eradicate them. This spells bad news for anyone with conditions such as cystic fibrosis, periodontitis, or chronic wounds as medical implants and catheters are hotspots for biofilm formation.
But why are biofilms so persistent, and what are doctors and scientists doing to outsmart these clever microbial communities?
What are biofilms?
“Biofilms are one of the most widely distributed and successful modes of life on Earth,” says Prof. Hans-Curt Flemming — director of the Institute for Interface Biotechnology at the University of Duisburg-Essen in Germany — in a 2016 article published in Nature Reviews Microbiology.
Biofilms can be made up of populations of the same bacteria or of communities, which, in turn, are made up of many different species, all living together under a protective dome.
This dome is composed of a so-called matrix of extracellular polymeric substances (EPS), which contains a mixture of sugars, proteins, fats, and DNA molecules.
In much the same way as human communities, biofilms have highly specialized areas: some of them are responsible for nutrient recycling, while others produce new EPS components or send messages from one area of the biofilm to another.
Living together in such close proximity allows bacteria to share resources more successfully than when they are in their free-living state. Crucially, it allows them to avoid conventional methods of eradication.