What is an adhesin?
An adhesin is a molecule on the surface of a microorganism, usually a protein, that lets it bind to a specific target such as a sugar or protein on a host cell, an extracellular-matrix component, or an abiotic surface. Adhesins can sit at the tip of long appendages (pili or fimbriae) or be anchored directly in the cell wall or outer membrane (non-fimbrial adhesins).
What is the difference between pili and fimbriae?
The two words are often used interchangeably for thin, hair-like protein fibres on the bacterial surface. Many authors use "fimbriae" for short adhesive fibres (for example type 1 fimbriae of E. coli) and "pili" more broadly, including conjugative (sex) pili and type IV pili that also mediate twitching motility.
Why do adhesins matter in infection?
Most pathogens must first attach to host tissue to avoid being washed away by flows such as urine, mucus or saliva. Adhesins also determine which tissues a microbe can colonise (tissue tropism), help trigger uptake into host cells, and start biofilm formation.
How are adhesins connected to biofilms?
Biofilm formation usually begins when bacteria attach to a surface through adhesins. The attached cells then produce an extracellular matrix of polysaccharides, proteins and DNA. Biofilms are much more tolerant of antibiotics and immune defences than free-swimming bacteria, which is why device-related infections are hard to treat.
Are anti-adhesion treatments available?
Most anti-adhesion approaches, such as FimH-blocking mannosides, pilicides and adhesin-based vaccines, are still investigational. Some products, such as D-mannose and cranberry preparations, have been studied for preventing urinary tract infections with mixed results. Nothing on this site is a treatment recommendation; talk to a healthcare professional.
Does adhesins.com give medical advice?
No. The site is purely educational and cannot answer personal medical questions. See the disclaimer.
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