The effects of topical Benzalkonium chloride (BAC) wound gel on chronic infections in Diabetes Related Foot Ulcers (DRFUs): An in vivo proof of concept study

We propose to undertake an in vivo pilot study in 20 diabetes related foot ulcers (DRFUs) complicated by chronic infections to identify the effects of a benzalkonium chloride-containing wound gel (BLASTX™). We will assess the total microbial load before, during and after therapy through quantitative polymerase chain reaction (qPCR) to estimate the number of bacteria. We will also use a combination of molecular and microscopy techniques (16S rDNA sequencing, Scanning electron microscopy [SEM], and peptide nucleic acid fluorescent in situ hybridisation [PNA-FISH]) to better understand the effects of the wound gel on in vivo biofilms and the microbiome. For the total duration of 12 weeks, the BAC wound gel will be applied to the ulcer every second day as the primary dressing. The total amount utilised will depend on the size of the wound, but application should cover the majority of the wound surface. A non-adhesive, adsorbent pad, such as a foam, will be used as a secondary dressing and secured to the foot with and adhesive, non-woven fabric tape. Participants may be asked to change their own dressings between follow ups or may have community nurses change their dressings in keeping with a normal dressing regime as per standard of care. The use of BAC wound gel does not constitute any additional dressing changes or visits to that of standard of care (SOC). SOC will be undertaken by a podiatrist, medical team and/or member of the research team. It involves performing appropriate wound bed preparation through conservative sharps debridement or curettage, wound cleansing with sodium chloride 0.9% and the replacement of a non-adherent, absorbent wound dressing. SOC may also involve offloading of plantar diabetes-related foot ulcers with a removable cast boot (DH Offloading Walker, Össur Australia) and for non-plantar DRFUs, a post-op shoe (Darco all-purpose boot, Össur Australia). Participants will be required to attend one thirty-minute appointment per week for the duration of the study (12 weeks or until healing is achieved). This is in keeping with the frequency of dressing changes and requirement for follow up as per SOC. At the initial, baseline appointment (week 0), participants will attend the Liverpool Hospital High Risk Foot Service and will be assessed as suitable (from the inclusion criteria) by the research podiatrist. If the individual consents to participation, a full wound history (including aetiology and lower limb vascular supply) and medical history (relevant demographic and medical data) will be recorded, a wound review (wound size, location, Wound, Ischaemia, foot Infection [WIfI] score) and wound photography will occur, as well as a wound swab and tissue curettage. Wound review and wound swab will be repeated at weeks 3, 6, 9 and 12 (end of study) or when healing is achieved (end of study) by the research podiatrist. An additional tissue curettage will occur at week 12 (end of study) by the research podiatrist if the wound is deemed suitable for this. Participants progress and adherence to the study will be followed closely by the research podiatrist through calendar scheduling and memos as well as a session attendance checklist. After this period, all participants may continue to be followed in the Liverpool Hospital High-Risk Foot Clinic by podiatry staff as part of their routine care especially if wound healing has not occurred.