Biofilms are communities of microbes that attach to and grow on surfaces (tooth plaque is the best-known example).
Biofilms also grow in chronic wounds and in some cases delay healing.
Biofilms are formed by microbes; mainly bacteria that are firmly embedded in the wound and encapsulated in a matrix which contains host material which makes treatment and dispersal problematic.
The microbes in a biofilm are protected from the patient’s immune system and antimicrobial agents such as antiseptics and antibiotics in 2 ways:
By the barrier formed by the protective coating
By becoming inactive or going to sleep (bacteria need to be active or awake to be susceptible to antibiotics)
Signs and symptoms of wound biofilm:
The absence of healing progression, even though all obvious comorbidities and wound management issues have been addressed
Visible, slimy gel-like shiny material on the surface of the wound bed which detaches easily and atraumatically from the wound bed
Re-forming of slough quickly, despite debridement
Poor quality granulation tissue – possibly fragile and hyper granulation
Signs of local infection
Failure to respond to antibiotic therapy
Increased exudate/ moisture level
Failure to respond to antiseptic treatment
Inconclusive or negative wound culture
It is reasonable to suspect a biofilm is causing a problem in chronic wounds that have not reduced in area by 40% after 4 weeks optimal standard care for the wound type that includes management of comorbidities or other relevant factors
Biofilms cannot be seen with the naked eye
Currently, there are no easy tests to detect biofilm in a wound and no tests to show when a wound biofilm is causing a problem. If the patient has received appropriate management for a chronic wound but the wound is slow to heal, it is logical to suspect that a biofilm is causing healing problems.
Reducing biofilm in chronic wounds
Repeatedly breaking up and removing the biofilm through vigorous/ active cleansing and or debridement
Reducing biofilm formation by decreasing the number of bacteria left in the wound through the use of an antimicrobial dressing or topical antiseptic preparation between each session of biofilm removal