Efficacy of phage cocktail AB-SA01 therapy in diabetic mouse wound infections caused by multidrug-resistant Staphylococcus aureus.

Background: Diabetic foot ulcer (DFU) is a serious complication of diabetes mellitus. Antibiotic-resistant Staphylococcus aureus is frequently isolated from DFU infections. Bacteriophages (phages) represent an alternative or adjunct treatment to antibiotic therapy. Here we describe the efficacy of AB-SA01, a cocktail of three S. aureus Myoviridae phages, made to current good manufacturing practice (cGMP) standards, and which has undergone two phase I clinical trials, in treatment of multidrug-resistant (MDR) S. aureus infections.
Results: Wounds of saline-treated mice showed no healing, but expanded and became inflamed, ulcerated, and suppurating. In contrast, AB-SA01 treatment decreased the bacterial load with efficacy similar or superior to vancomycin treatment. At the end of the treatment period, there was a significant decrease (p < 0.001) in bacterial load and wound size in infected phage- and vancomycin-treated groups compared with infected saline-treated mice. In phage-treated mice, wound healing was seen similar to vancomycin treatment. No mortality was recorded associated with infections, and post-mortem examinations did not show any evident pathological lesions other than the skin wounds. No adverse effects related to the application of phages were observed.
Conclusion: Topical application of phage cocktail AB-SA01 is effective, as shown by bacterial load reduction and wound closure, in the treatment of diabetic wound infections caused by MDR S. aureus. Our results suggest that topical phage cocktail treatment may be effective in treating antibiotic-resistant S. aureus DFU infections.