Topical erythritol combined with L-ascorbyl-2-phosphate inhibits staphylococcal growth and alleviates staphylococcal overgrowth in skin lesions of canine superficial pyoderma

Erythritol (ERT) and L-ascorbyl-2-phosphate (APS) are bacteriostatic, but their effects on staphylococcal skin infections remain unknown. We aimed to determine whether ERT combined with APS inhibits the growth of staphylococci that are commonly isolated from pyoderma skin lesions in dogs. We investigated the individual and combined effects of ERT and APS on the growth of Staphylococcus pseudintermedius, S. schleiferi, and S. aureus using turbidity assays in vitro. Skin lesions from 10 dogs with superficial pyoderma were topically treated with 5% ERT and 0.1% APS for 28 days, and swabbed skin samples were then analyzed using 16S rRNA amplicon sequencing and quantitative real-time PCR (qPCR). Results showed that ERT inhibited S. pseudintermedius growth regardless of harboring the mecA gene, and APS increased the inhibitory effects of ERT against S. pseudintermedius, S. schleiferi, and S. aureus in vitro. Moreover, combined ERT and APS decreased the prevalence of staphylococci on canine skin lesions at the genus level. The combination slightly increased the α-diversity but did not affect the β-diversity of the microbiota. The qPCR results revealed that the combination significantly decreased S. pseudintermedius and S. schleiferi in skin lesions. Topical administration of EPS combined with APS can prevent staphylococcal colonization on the surface of mammalian skin. The results of this study may provide an alternative to systemic antibiotics for treating superficial pyoderma on mammalian skin surfaces.

Clinical effects of combined Lactobacillus paracasei and kestose on canine atopic dermatitis

Probiotics and prebiotics are viable bacteria with beneficial effects on the host and components that selectively act on the beneficial commensal bacteria, respectively. The combined use of probiotics and prebiotics is termed synbiotics. Probiotic intake improves dysbiosis in the intestinal microbiota and can positively affect canine atopic dermatitis (CAD). However, clinical studies on improvements in CAD using synbiotics remain limited. In this study, 15 dogs with CAD who received prednisolone, a synthetic glucocorticoid (GC) used in the treatment of CAD, for more than 90 days were continuously treated with Lactobacillus paracasei M-1 from fermented food as a probiotic, and trisaccharide kestose as a prebiotic, for 90 days to determine their synbiotic effects on CAD. The CAD symptoms were evaluated using the canine atopic dermatitis lesion index (CADLI) and pruritus visual analog scores (PVAS) at 30, 60 and 90 days after synbiotic administration. The total prednisolone use for 90 days pre- and post-administration was also evaluated. Synbiotic administration significantly reduced the CADLI (pre: median, 28.0 [22.0-32.0]; 30 days: median, 20.0 [20.0-28.0]; 60 days: median, 20.0 [10.0-21.0]; 90 days: median, 12.0 [10.0-19.0]) and PVAS (pre: median, 6.0 [5.0-7.0]; 30 days: median, 3.0 [3.0-3.5]; 60 days: median, 3.0 [3.0-3.5]; 90 days: median, 2.0 [2.0-3.5]) scores, and reduced the total prednisone use over 90 days (pre: 112.0 [25-450] mg; post: 80.0 [18.-300.0] mg; p⟨0.001) in the 15 dogs. Thus, the synbiotic activity of L. paracasei M-1 and trisaccharide kestose can improve CAD.

The bacteriostatic effect of erythritol on canine periodontal disease-related bacteria

Erythritol helps both prevent and improve periodontal disease and is therefore widely used for dental care in humans. However, only a few studies have investigated the effects of erythritol on periodontal disease in animals. We hypothesized that erythritol could be used to prevent and improve periodontal disease also in canines and investigated the effects of erythritol on canine periodontal disease-related pathogenic bacteria using both in vitro and in vivo methods. The effect of erythritol on the proliferation of Porphyromonas gulae, which is reportedly associated with canine periodontal disease, was investigated in vitro. In addition, a 4-week intervention trial using an external gel preparation containing 5% erythritol was performed in canines with mild periodontal disease; changes in the microbiota around periodontal lesions were investigated using next-generation sequencing and bioinformatics analysis. The growth of P. gulae was significantly suppressed by erythritol in vitro. In the intervention study, the Shannon index, an indicator of the species distribution α-diversity, and the occupancy of several canine periodontal disease - related bacteria ( P. gulae, P. cangingivalis) were significantly decreased in periodontal lesions. Based on the results of in vitro and in vivo studies, we conclude that, as in humans, erythritol has bacteriostatic effects against periodontal disease - related bacteria in canines.