Some sources claim that almost 80% of chronic wounds are colonised with biofilm. Biofilm has a significant tolerance to antibiotics and biocides while remaining protected from host immunity. While awareness of the presence and impact of wound biofilm has advanced enormously, understanding of its pathogenesis is yet to be clarified fully.

The International Wound Infection Institute (IWII) has released an updated version of Wound Infection in Clinical Practice which was published in 2008 by the World Union of Wound Healing Societies (WUWHS). The update comes as a result of a comprehensive literature review and formal Delphi process.

Key updates in this edition appraised the wound infection continuum which includes biofilm. Some commentary has suggested that ‘foreign’ material on a wound surface represents biofilm. However, many wounds that appear to be healthy are shown via laboratory investigation to have biofilm that contributes to stalled healing.

According to the new Wound Infection in Clinical Practice document, the following are indicative characteristics of potential biofilm:

• Failure of appropriate antibiotic treatment
• Recalcitrance to appropriate antimicrobial treatment
• Recurrence of delayed healing on cessation of antibiotic treatment
• Delayed healing despite optimal wound management and health support
• Increased exudate/moisture
• Low-level chronic inflammation
• Low-level erythema
• Poor granulation/friable hypergranulation
• Secondary signs of infection

The presence of biofilm in wounds can be confirmed through microscopic techniques. Biofilms need to be reduced or eliminated for the wound to heal. Currently, the most effective method of eliminating biofilms is physical removal through debridement. Another less than effective method to try is the application of effective antimicrobials, antibiotics or antiseptics.

Professor Greg Schultz from of the Institute of Wound Research at the University of Florida said, “Aggressive debridement is one of the most important strategies against biofilms but as biofilms can reform rapidly within 24 hours post debridement, antimicrobials are also required to effectively tackle wound biofilms.”

Terry Swanson from the IWII said that they wanted to develop clear recommendations for understanding, diagnosing and treating biofilms in chronic wounds using responses from 1223 wound clinicians globally who participated in the online survey last year.

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Image: Hans – pixabay