Bacterial skin infections, particularly pyoderma and otitis externa, are widespread in dogs, primarily caused by Staphylococcus and Pseudomonas species. This study evaluates the prevalence and types of bacterial pathogens in affected dogs in South Korea using a meta-analytical approach. Following the PRISMA guidelines, five electronic databases were searched for relevant studies published between 1990 and 2024. Three researchers independently performed data extraction and quality assessment. A subgroup analysis explored the variability in pathogen prevalence across studies based on bacterial genus, bacterial species, publication year, sampling year, sampling location, infection type, diagnostic method, and sample size. Publication bias was evaluated using funnel plots and Egger’s regression test, with all analyses conducted using the R program. Of the 944 articles, 29 met the eligibility criteria. The pooled bacterial prevalence among infected dogs was 99.95% (95%CI: 99.85–100). Staphylococcus was the most prevalent genus (95.93%), followed by Pseudomonas (48.43%), Enterococcus (20.32%), and Escherichia (17.63%). The most common species were Staphylococcus pseudintermedius (78.89%), Staphylococcus intermedius (71.43%), and Pseudomonas aeruginosa (46.13%). This study underscores the need for comprehensive treatment strategies targeting Gram-negative and Gram-positive bacteria, emphasizing further research on antimicrobial resistance patterns and treatment efficacy to enhance canine health outcomes in South Korea.

Background: Understanding the physiological and biophysical characteristics of skin provides information for developing appropriate management strategies for skin diseases. However, in dogs, variations in skin biophysical parameters, such as age, sex and breed, remain poorly understood.Hypothesis/Objectives: This study analysed three biophysical characteristics of healthy dog skin (hydration, pH and sebum content) and investigated the effects of sex, age and breed.Materials and Methods: One hundred forty‐nine dogs without skin problems were enrolled. Skin hydration, pH and sebum content were measured using a multifunctional skin physiology monitor. The dogs were divided into four age groups: 13 years.Results: Skin hydration levels were significantly lower in the >13 years group than in the 1–6 years and 7–12 groups. Additionally, skin pH levels in the >13 years group were significantly lower than in the 7–12 group. Furthermore, skin biophysical parameters among the five breed groups – beagles (n = 37), Malteses (n = 18), miniature poodles (n = 24), cocker spaniels (n = 11) and Pomeranians (n = 12) – revealed that skin hydration and pH were significantly higher in beagles than those of Malteses and miniature poodles.Conclusions and Clinical Relevance: These findings indicate that biophysical properties, including skin hydration and pH, vary with age and breed. This study provides fundamental data on the effects of age, sex and breed on the biophysical characteristics of dog skin.

Activated keratinocytes play a crucial role in skin inflammation through the production of multiple inflammatory mediators; however, little is known about cytokine secretion by activated keratinocytes in dogs. This study aimed to investigate the effects of the Th1 and Th2 types of cytokines on the production of keratinocyte-derived inflammatory mediators. Canine progenitor epidermal keratinocytes (CPEKs) were incubated with canine recombinant IL-4, IL-13, an IL4/IL13 mixture, IFN-γ, TNF-α, or an IFN-γ/TNF-α mixture for 24 h following 100% confluency. Culture supernatants were analyzed for cytokine concentration, including chemokine ligand (CXCL) 8, IL-10, IL-6, IL-1ß, IL-12, and chemokine ligand 2 (CCL2) by enzyme-linked immunosorbent assay. CPEKs incubated with the IFN-γ/TNF-α mixture showed significantly increased IL-6 concentration. In addition, significantly increased concentrations of CXCL8 were detected in CPEKs incubated with TNF-α and with the IFN-γ/TNF-α mixture. CCL2 concentrations increased in cells incubated with IFN-γ, TNF-α, and the IFN-γ/TNF-α mixture. The IFN-γ/TNF-α mixture synergistically enhanced CCL2 production. Dose-dependent elevations were also observed in IL-6 in response to the IFN-γ/TNF-α mixture, and in CCL2 in response to IFN-γ, TNF-α, and the IFN-γ/TNF-α mixture. These findings indicate that IFN-γ and TNF-α synergistically increase pro-inflammatory cytokines and chemokines secreted by canine keratinocytes. This in vitro culture system could be useful to investigate cytokine-mediated crosstalk between keratinocytes and immune cells and new therapeutic strategies for keratinocyte-mediated inflammatory skin diseases.