Larval Debridement Therapy Versus Sharp Debridement to Remove Biofilm

Drug resistant organisms and bacterial biofilm pose an increasing threat to the health of millions of individuals world-wide. These organisms are being identified with an alarming prevalence among persons with chronic wounds. The presence of necrotic tissue has been associated with the deterioration of open wounds and serves as a breeding ground and nutrient source for bacteria. The removal of necrotic tissue is widely accepted as required for optimal wound healing.

The primary purpose of this study is to assess the efficacy of larval debridement therapy (LDT) with bagged, sterilized, live, medicinal blow fly (Lucilia sericata) larvae (or " BioBags") versus bedside sharp debridement in removing harmful bacteria, biofilm and necrotic tissue from chronic wounds to promote wound healing. Characteristics associated with chronic wound environments will be evaluated through analysis of samples of tissue taken from wound beds before and after both types of debridement. One hundred and forty patients ≥ 21 years of age (and their caregivers and wound providers)with an open, full thickness wound which is healing by secondary intention (of greater than 8 weeks duration and requires debridement) will be invited to participate. This recruitment number accounts for estimated 10% attrition rate, so final sample number is anticipated to be 296 or 128 Veteran subjects (64 in each arm) and 128 caregivers, and 6 providers (and total of 34 subjects which may be lost to follow up). Samples of wound bed tissue and slough tissue (if present) will be collected on Days 0, 4 and 8 or prior to and after each larval debridement intervention or sharp debridement (control). Photos will be taken of the wound bed on Days 0, 4 and 8 or just prior to and after each debridement method. A randomized sampling procedure will place individuals into one of two groups: The intervention group will receive larval debridement therapy once every 4 days for 2 applications (with saline moistened gauze as cover dressing changed daily) and the control group will receive sharp debridement therapy every 7 days for 2 debridements (with wound gel dressing changed daily).

Inclusion criteria

• Veterans over 21 years of age
• with chronic lower extremity or diabetic foot ulcers (wound duration over 8 weeks)
• who at the clinician's judgment requires wound debridement (25% or more of wound bed covered with non-viable tissue)
• wound size 1.5 cm (roughly the size of a quarter) or larger in diameter

Exclusion criteria

• Cognitive impairment that would interfere with patient signing own Informed Consent
• Veterans on active anticoagulant therapy with most recent (within last week) PT/INR (international normalized ratio of prothrombin time) > 3.0, or other significant bleeding risk
• Active immune suppression just prior to or during study (on systemic corticosteroids* within 7 days prior, or chemotherapy for cancer or RA treatment within 4 weeks prior to study, or with diagnosis of HIV/AIDS) - *Nasal steroid sprays will not be excluded
• Active systemic antibiotics is an exclusion
• Absent dorsalis pedis pulses and Ankle Brachial Index (ABI) < 0.5 is an exclusion (indicates critical limb ischemia).
• Other possible reasons participants could be removed from this study include: transfers to other non-VA facilities, participant is unable to tolerate tissue sampling even with local anesthesia, and/or inability to comply with scheduled research visits. Furthermore, if the participant has significant wound healing so that sampling is not possible after the initial sampling, they will be removed from the study.