RELEVANCE: For patients within the VA healthcare system, diabetic foot ulcers constitute a significant portion of treatment and therapy. Among all complications in patients with diabetes none is more common, costly and complex than foot infections. When these wounds are complicated by biofilm-forming bacteria, the problem becomes particularly challenging as biofilms contribute to chronic, difficult-to-treat infections that lead to morbidity and amputation. In cases of infected diabetic foot ulcers and chronic wounds, two of the most common pathogens cultured are Staphylococcus aureus (with methicillin-resistant S. aureus (MRSA) of particular concern) and Pseudomonas aeruginosa—organisms that readily form biofilms. To address these problems, we have synthesized and developed CZ compounds. CZs are a patented and unique first-in-class series of antibiofilm antibiotics with reduced risk of resistance development that disperse and kill well-established biofilms. They also work synergistically with traditional antibiotics, which provides the potential to not only address the problem of biofilm-related infections, but to improve current clinical treatments. OBJECTIVES: The immediate objective is to test the efficacy of an innovative antibiofilm therapy to treat and prevent biofilm-related infection in a diabetic pig excision wound model. Long-term, the objective is to translate this technology for testing CZs in the clinic. With the collaboration of Larry Meyer, MD, PhD and Don Granger MD who treat VA patients regularly—a large portion of which suffer from diabetic foot ulcers—once in vivo animal data is collected, our group can work with the FDA to perform investigator-initiated studies and directly translate the technology to the clinic to reduce morbidity, cost, duration of hospitalization/clinic visits, and the length of rehabilitation in our Veterans. HYPOTHESES: 1) When used as a topical gel, CZ compounds will treat and prevent monomicrobial and polymicrobial biofilm-related infection of MRSA or P. aeruginosa in a diabetic pig excision wound model. 2) CZ compounds will act synergistically with antibiotics that are currently used clinically and will improve their ability to treat and prevent biofilm-related infections caused by MRSA and P. aeruginosa in a diabetic pig excision wound model. PROCEDURES: Aim 1a: Will focus on in vitro optimization against monomicrobial and polymicrobial biofilms of methicillin-resistant Staphylococcus aureus (MRSA) and P. aeruginosa. In vitro efficacy profiles of CZs have been well-documented, which is important because this means that the success of Aim 1b and Aim 2 will not be solely dependent on the success of Aim 1a. Nevertheless, in Aim 1a we propose to perform in vitro analysis of the CZ technology to optimize dose and gel formulation to eradicate monomicrobial and polymicrobial biofilms. Aim 1b: Will involve in vivo analysis of CZ efficacy against monomicrobial and polymicrobial biofilm-related infections in diabetic pig excision wounds that will be inoculated with MRSA, P. aeruginosa or both. Aim 2: Will involve the same pig model as Aim 1b, but will include the additional component of parenteral administration of traditional antibiotics in combination with topical CZ treatment. The efficacy of this combined therapy will be tested against monomicrobial and polymicrobial biofilm-related infections of MRSA and P. aeruginosa. SIGNIFICANCE OF FINDINGS: These studies will address two important clinical gaps in Veterans' healthcare and civilians: 1) A directed approach that targets and eradicates biofilms that complicate diabetic foot ulcer infections and 2) the development of novel antibiofilm strategies that address the current global threat of antibiotic resistance. In this proposal, a directed approach will be taken to test the efficacy of a unique first-in-class series of antibiofilm antibiotics that have reduced risk of resistance, and have been piloted in vivo showing their ability to treat and prevent biofilm-related infection. The long-term goal is to reduce the number of clinic visits for patients who suffer from foot ulcer infections, lower healthcare costs and improve quality of life for our Veterans.

Diabetic foot ulcers in Veteran patients are often complicated by contamination and growth of bacteria that cause infection. Bacteria in wounds can form what are referred to as biofilms—communities of bacteria that are very difficult to treat. When skin infections don't respond to antibiotic therapy, they may become chronic and cause patients to suffer, and perhaps require amputation. Our study is designed to develop a new type of antibiofilm antibiotic that kills biofilms and prevents chronic infections from occurring.