Biofilms: Cities of Microorganisms

Recently, I came across an interesting article published on the ASM (American Society for Microbiology) website, which discussed the resistance to disinfection of Listeria monocytogenes biofilms.

But what are biofilms anyway?

According to the IUPAC definition, biofilms are aggregates of microorganisms in which the cells are often inserted inside a matrix produced by themselves, constituted by extracellular polymeric substance (EPS) – a polymeric conglomeration of extracellular DNA, proteins, and polysaccharides – adhering to each other and/or to a surface.

A biofilm is, therefore, a system in which its inhabitants have not only the ability to adapt it internally to environmental conditions but also to communicate with each other, for example, in the case of bacteria biofilms, through a process called quorum sensing.

At the clinical level, the formation of these communities in hosts may lead to drug resistance and inflammation, which in turn may result in persistent infections. In fact, we have all probably contacted with biofilms since they are thought to be responsible for 80% of all microbial infections, from common urinary tract infections to more serious infections such as endocarditis. In fact, dental plaque itself is a biofilm of Streptococcus mutans and other anaerobic bacteria!


ASM article:



  1. How interesting. My previous job involved managing patients with chronic wounds, and biofilms are discussed in the wound care literature. Like dental plaque, they present as tissue called slough adherent to the wound, and part of the treatment involved removing it, either chemically or manually by debridement ( using a scalpel or sharp curette.) . This often had to be repeated weekly until a wound fully healed. Bacteria apparently can be tenacious!

    Liked by 1 person

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