In vitro efficacy of 0.2% and 0.4% sodium oxychlorosene against meticillin‐resistantStaphylococcus pseudintermedius

Abstract

Background There is a need for alternative topical therapies as a consequence of the increased prevalence of meticillin‐resistant Staphylococcus pseudintermedius (MRSP) skin infections in dogs. Sodium oxychlorosene has been used as a topical antibacterial agent in human medicine since 1955. Objectives To determine whether 0.2% and 0.4% sodium oxychlorosene solutions have a bactericidal effect (>3‐log reduction) on MRSP strains isolated from canine skin infections. Methods and materials A genetically heterogeneous collection of MRSP isolates from dogs was assembled from laboratories across the United States. Time–kill assays were performed with 0.2% and 0.4% sodium oxychlorosene on a 0.5 McFarland standard [approximately 108 colony‐forming units (cfu/ml)] suspension of each strain. The average bacterial counts (cfu/ml) of each MRSP strain then were determined at 5, 10, 20 and 60 s after exposure to sodium oxychlorosene; cfu/ml data were converted to log10 scale to calculate microbial reduction. Results The average bacterial counts following exposure to the 0.2% solution at 5, 10, 20 and 60 s were 6.94 × 104, 5.63 × 103, 2.96 × 102 and 1.48 × 102 cfu/ml, respectively. For the 0.4% solution, the average bacterial count at 5 s was 2.12 × 103 cfu/ml. No bacterial growth was observed for any MRSP strain by 10 s. The greatest reduction in cfu/ml occurred within 5 s following exposure to each solution 3.4‐log and 4.9‐log reduction for 0.2% and 0.4%, respectively. Conclusions and Clinical Relevance 0.2% and 0.4% sodium oxychlorosene solutions have a bactericidal effect (>99.9% reduction) against MRSP in vitro. Further in vivo studies are necessary to determine whether it is an appropriate alternative therapy for canine pyoderma

Topical therapy for canine pyoderma: what is new?

“…When sodium oxychlorosene is dissolved in water, the hypochlorous acid is released acting as a detergent and oxidizing agent. 61 Sodium oxychlorosene is extremely safe and it has been used for decades in human medicine to treat a variety of infections. Sodium oxychlorosene is reconstituted to a concentration of 0.2% to 0.4% for topical use, with the 0.2% solution being safer periocularly.…”

“…Sodium oxychlorosene is reconstituted to a concentration of 0.2% to 0.4% for topical use, with the 0.2% solution being safer periocularly. 61 Sodium oxychlorosene solution can be applied as irrigation, spray, wet wound packs, or as a bath rinse up to 4 times daily. 61 Very recently, a pilot study 61 testing the in vitro efficacy of 0.2% and 0.4% sodium oxychlorosene solution against MRSP isolates (n = 27) has been published.…”

“…61 Sodium oxychlorosene solution can be applied as irrigation, spray, wet wound packs, or as a bath rinse up to 4 times daily. 61 Very recently, a pilot study 61 testing the in vitro efficacy of 0.2% and 0.4% sodium oxychlorosene solution against MRSP isolates (n = 27) has been published. Sodium oxychlorosene was able to rapidly kill bacteria at both concentrations tested.…”