Efficacy study of a topical treatment with a plant extract with antibiofilm activities using an in vivo model of canine superficial pyoderma

Background Canine pyoderma is a common skin infection caused predominantly by staphylococcal bacteria. Because of increasing rates of antimicrobial resistance in bacterial isolates, there is an urgent need for alternative or supplementary treatment options. W16P576, a Water Extract of Complex Mix of Edible Plants (WECMEP), has shown in vitro activity against a variety of bacteria, including Staphylococcus pseudintermedius. A canine model of pyoderma was developed which allows in vivo testing of antimicrobial agents in a controlled environment. Objective To evaluate the antibacterial efficacy of topical application of W16P576 in a model of canine pyoderma. Animals Nine laboratory housed beagle dogs. Methods and materials In an evaluator-blinded cross-over study with an eight week washout period, dogs were treated topically twice daily with W16P576 WECMEP or its vehicle, starting three days before bacterial challenge. On the day of challenge, each dog was treated with two concentrations of a clinical S. pseudintermedius strain on opposite sides of the body. Topical treatment was continued for 11 days and lesions of pyoderma were evaluated and scored for 14 days. Results All dogs developed lesions consistent with bacterial pyoderma. Lesion scores were generally higher on the side inoculated with a higher concentration of bacteria. Treatment with W16P576 significantly reduced lesion development and hastened resolution of lesions, compared to placebo. Conclusion Topical application of W16P576 markedly reduced lesion development in this proof of principle study. Clinical trials are warranted to estimate benefits for dogs with naturally occurring pyoderma under field conditions.