Treatment of Chronic Wound Biofilms

Chronic wounds lead to significant patient morbidity and mortality, and its treatment is associated with a global economic burden of $13-$15 billion annually. In Canada, the average cost of three months of community care for a chronic wound is $ 27,600.00. One of the major complications associated with chronic wounds is colonization with a Staphylococcus aureus (S. aureus) biofilm. These bacterial biofilms delay re-epithelialization and prevent wound healing. Standard treatment of chronic wound biofilms includes aggressive debridement as well as the addition of anti-biofilm agents such as antimicrobials. Since antimicrobial resistance is becoming a serious problem, finding alternatives is essential.

Staphylococcus epidermidis (S. epidermidis) JK16 cells, their culture supernatants and a serine protease (Esp) in the culture supernatants have been shown to inhibit the formation of and destroy preexisting S. aureus biofilms. The investigators hypothesize that the use of S. epidermidis JK16, culture supernatants or purified Esp protein in the standard wound care protocol will breakdown S. aureus biofilms, decrease bacterial colonization of chronic wounds and improve healing times. The investigators will employ a two-way cross over study where participants will receive standard wound care or S. epidermidis JK16 Esp supplemented treatment for the first 6 weeks followed by cross over for a further 6 weeks. These patients will be recruited from the Wound Healing Clinic at Vancouver General Hospital. Standard wound care will be provided in accordance with established protocols based on "Best Clinical Practice Guidelines for Venous Leg Ulcers" from the Canadian Association of Wound Care. For the S. epidermidis JK16 Esp supplemented treatment arm, the investigators will produce purified Esp and impregnate wound dressings with this protein. After 6 weeks, participants will be crossed over to the corresponding treatment arm.

Our primary outcome measure will be healing rate as calculated for each 6 week standard or experimental treatment periods. The investigators will employ standardized photography and wound image analysis software to calculate the healing rate. Other outcome measures will include visual detection and qualitative assessment of biofilms as determined by trained nurses and/or physicians. Finally, bacterial type and quantity will be determined by wound biopsy. Outcome measures for standard treatment arms will be compared with results from S. epidermidis JK16 Esp supplemented treatment arms. Objectives of this pilot study include:

1. To assess the feasibility of conducting a more definitive trial to examine the efficacy of S. epidermidis Esp protein from strain JK16 in healing chronic wounds
2. To perform a pilot study using a cross-over design with the purified S. epidermidis Esp protein from strain JK16 in comparison to standard therapy
3. To demonstrate that the intervention is acceptable to participants
4. To demonstrate the safety of the intervention
5. To explore the biologic activity of S. epidermidis Esp protein from strain JK16 on wound biofilms and healing times