Veterinary dermatology最新文献

Background: Antimicrobial stewardship has become vital given the progressive emergence of multidrug-resistant bacteria, and novel approaches to the treatment of bacterial infections are needed. Recently, reported synergistic effects of antibacterial drugs and bacteriophage therapy have revealed promising applications for the management of meticillin-resistant staphylococcal infections.

Objectives: The objective of this study was to investigate the response of meticillin-resistant Staphylococcus pseudintermedius (MRSP) to treatment with a newly isolated, lytic MRSP-specific bacteriophage. Furthermore, a postulated synergism between phage and fusidic acid was examined in a canine ex vivo dermis model.

Material and methods: Skin was harvested from the lateral thorax of a euthanised dog, clipped, the subcutis removed, and epidermis cleaved via a modified salt-split technique. The ex vivo dermis model established in Franz diffusion cells was inoculated with 1 × 10⁷ colony-forming units (cfu) of a clinical MRSP strain for 16 h. Then, experimental groups were treated with phage vB_SpsS_LmqsKl44-4 at a concentration of 2 × 10⁶ plaque-forming units and fusidic acid 0.4 mg alone or in combination for an additional 8 h.

Results: Histopathological results showed that colonies of MRSP reached the superficial dermis and entered hair follicles. Co-treatment with fusidic acid and phage significantly reduced the amount of MRSP after 8 h.

Conclusions and clinical relevance: In conclusion, topical co-treatment with fusidic acid and a phage could be a promising approach to the treatment of canine MRSP pyoderma.

Background: Canine atopic dermatitis (cAD) is a complex skin disease characterised by barrier dysfunction. Studies regarding the role of skin surface lipids (SSL) in cAD are needed.

Objectives/hypothesis: Evaluate the feasibility of using D-squame tape-stripping for SSL collection and ultra-high-performance liquid chromatography coupled with high-resolution mass spectrometry (UHPLC-HRMS) for untargeted lipidomic analysis. A secondary objective was to identify significant differences in SSL between atopic and healthy dogs, and between different body sites.

Animals: Sixteen client-owned Labrador retrievers, eight atopic and eight healthy were recruited through vaccination or dermatology appointments.

Materials and methods: Skin samples were collected from three body sites (thigh, interdigital and inguinal) using D-Squame tapes. Untargeted lipidomic analysis was conducted using UHPLC-HRMS, and data were processed with MS-DIAL and LipidSearch software.

Results: This study identified 114 SSLs, predominantly ceramides (66.2%) and diacylglycerols (30.5%). The percentage of lipid classes and ceramide subclasses did not significantly differ between healthy and atopic dogs. Two ceramide and two triacylglycerol species were significantly higher in atopic dogs, while another two ceramide species were significantly lower. Additionally, notable regional differences in lipid profiles were observed.

Conclusions and clinical relevance: Our findings suggest that D-squame tape-stripping combined with UHPLC-HRMS is a feasible method for SSL research in cAD. Lipid species-specific differences and significant regional variations were found, emphasising the importance of considering body sites in future studies. This study underscores the need for further research to understand the role of SSL in cAD and the insights that untargeted lipidomic analysis can provide.

Background: Allergen immunotherapy is used as aetiological treatment for canine atopic dermatitis (cAD).

Objective: To assess the anti-inflammatory agent-sparing effect over 1 year of immunotherapy using pullulan-conjugated recombinant Der f 2 (rDf2-P).

Animals: Twenty-one privately owned dogs with cAD.

Materials and methods: Dogs with mild clinical signs after ≥4 weeks of anti-inflammatory drug treatment received rDf2-P immunotherapy for 1 year. A monthly medication score (MS) was calculated, and clinical signs were assessed using Canine Atopic Dermatitis Extent and Severity Index (CADESI)-04, cAD Eczema Area and Severity for Shiba Inu and pruritus scores. Serum thymus and activation-regulated chemokine (TARC)/C-C Motif Chemokine Ligand-17 (CCL17) concentrations were assessed at the initial and final doses during the 6-week induction phase and every 3 months for 1 year thereafter in 16 cases.

Results: The mean MS decreased significantly by 43.0% (p = 0.022), 60.9% (p = 0.003), 70.0% (p = 0.0004), 58.7% (p = 0.0004) and 49.3% (p = 0.029) at 2.5, 4.5, 7.5, 10.5 and 13.5 months, respectively. Drug-sparing effects, assessed with MS and adjusted by clinical scores were rated as excellent for 12 (57.1%) and 11 (52.4%) dogs, good for 3 (14.3%) and 1 (4.8%) dogs, fair for 0 and 3 (14.3%) dogs, and poor for 6 (28.6%) and 5 (23.8%) dogs at 4.5 and 13.5 months, respectively. The serum TARC/CCL17 concentrations were significantly lower in the samples with lower CADESI-04 scores (<17) than in those with higher CADESI-04 scores (>17) (p = 0.0002).

Conclusions and clinical relevance: Der f 2-P immunotherapy can lead to a rapid reduction in anti-inflammatory drug use and serve as an effective proactive therapy for cAD.

Background: Itch is a common clinical sign in skin disorders. While the neural pathways of itch transmission from the skin to the brain are well understood in rodents, the same pathways in dogs remain unclear. The knowledge gap hinders the development of effective treatments for canine itch-related disorders.

Hypothesis/objectives: This study aimed to investigate the differential gene expression in the dorsal root ganglia (DRGs) between healthy and atopic dogs to identify specific molecules potentially involved in itch signalling and neuroinflammation in canine atopic dermatitis (cAD).

Animals: Two atopic and four healthy dogs.

Materials and methods: DRGs were collected from atopic and healthy dogs to compare their transcriptional profiles using RNA sequencing.

Results: Principal component and heatmap analyses revealed two distinct clusters separating atopic from healthy dogs. Consistent with this observation, we identified 627 (543 upregulated and 84 downregulated) differentially expressed genes (DEGs) in atopic compared with healthy dogs. We further narrowed down our genes of interest to common DEGs in each atopic dog, which revealed 159 (132 upregulated and 27 downregulated) DEGs. Among these genes, when we focused on itch signalling-associated molecules, P2RY12, IL-2RG, TLR1 and POSTN were significantly upregulated, while MRGPRD and LPAR3 were both significantly downregulated in atopic dogs compared with those in healthy dogs. Pathway analysis showed a significant upregulation of CREB signalling in neurons, myelination signalling and neuroinflammation signalling pathways in atopic dogs.

Conclusions and clinical relevance: Our study suggested that dysregulation of neuroinflammatory pathways might play a role in the pathomechanism of cAD as in humans.

Atopic dermatitis (AD) is a common and chronic inflammatory skin disease with frequent relapses. The genomics revolution has greatly contributed and revolutionised our knowledge of human AD; understanding the molecular skin fingerprint of AD and associated pathogenic immune pathways has led to preclinical assessments of several novel treatments. Initial studies using microarray analysis to analyse transcriptome (gene expression) changes provided relevant insight on the inflammatory and structural changes occurring at the time of acute or chronic AD skin lesions, or after immunomodulating treatments with drugs ciclosporin and dupilumab, a monoclonal antibody anti-IL4 receptor. The studies revealed that human AD is characterised by the activation of multiple cytokine pathways (predominance of T helper cell [Th]2 with some activation of Th1, Th17 and Th22) as well as dysregulated expression of barrier components in the skin. There are several reports on the expression of different single molecular targets (e.g. interleukin [IL]-13, CCL17 and periostin) in spontaneous canine AD (cAD). However, significant studies of the transcriptome have been limited to a single microarray study analysing chronic AD skin lesions in dogs. While revealing a large number of genes differentially expressed in cAD skin, the small sample size (n = 13 dogs) and the lack of changes in key epidermal barrier and inflammatory cytokine genes in the microarrays have inhibited discussion towards specific immunological changes. This review summarises the current literature regarding the molecular mechanisms of spontaneous cAD, including the recent data regarding RNA sequencing, and compares some pathogenic aspects to the previously published data from human AD.

Background: Early and accurate diagnosis of otitis externa is crucial for correct management yet can often be challenging. Artificial intelligence (AI) is a valuable diagnostic tool in human medicine. Currently, no such tool is available in veterinary dermatology/otology.

Objectives: As a proof-of-concept, we developed and evaluated a novel YOLOv5 object detection model for identifying healthy ear canals, otitis or masses in the canine ear canal.

Animals: Digital images of ear canals from dogs with healthy ears, otitis and masses in the ear canal were used.

Materials and methods: Four variants of the YOLOv5 model were trained, each using a different training dataset. The prediction performance metrics used to evaluate them include F1/confidence-curves, mean average precision (mAP50), precision (P), recall (R) and average precision (AP) for accuracy. These are quantifiable performance metrics used to evaluate the efficacy of each variant.

Results: All four variants were capable of detecting and classifying the ear canal. However, training datasets with many duplicates (A and C) inflated performance metrics as a consequence of data leakage, potentially compromising their effectiveness on unseen images. Additionally, larger datasets (without duplicates) demonstrated superior performance metrics compared to model variants trained on smaller datasets (without duplicates).

Conclusions and clinical relevance: This novel AI object detection model has the potential for application in the field of veterinary dermatology. An external validation study is needed prior to clinical deployment.

Background: The history of otology and otitis externa (OE) goes back to the earliest days of medicine, with notations made in early Egyptian writings and evolving to our modern-day textbooks and publications.

Conclusions and clinical relevance: The history of OE in dogs is closely tied to the history of otology and veterinary dermatology, and introduces us to early and recent researchers and writers in the fields of medicine, veterinary medicine and otology.

Uveodermatological syndrome and alopecia areata are autoimmune disorders causing ocular and dermatological inflammation and alopecia, respectively, in dogs. This is the first report to document concurrent development of the two diseases in a dog, as has been reported in human patients. Clinical presentation and histopathological diagnosis, treatment and clinical follow-up are described.

Background: In humans, food allergies (FAs) are divided into those with immunoglobulin (Ig) E-mediated (immediate FA), cell-mediated (delayed FA) or both mechanisms (mixed FA). In dogs, lymphocyte stimulation tests have the highest concordance with oral food challenges (OFCs).

Objectives: To report the evaluation of a lymphocyte proliferation test (LPT) in dogs with FA and delayed reactions (≥6 h) after OFC.

Animals: Thirty-five healthy and 28 dogs with delayed FA.

Materials and methods: Peripheral blood mononuclear cells (PBMCs) were isolated and automatically counted before and after a 5-day culture with food allergens. Stimulation indices (SIs) were then calculated. Food allergen-specific IgE was quantified using the Pet Allergy Xplorer (PAX).

Results: None of the 10 healthy laboratory beagles and 25 healthy pet dogs had an SI greater than the 3.0 cut-off, indicating a specificity of 100%. All 28 dogs with delayed FA had at least one positive stimulation to a food item that induced delayed flares after OFC; the sensitivity of this LPT for the identification of delayed canine FA was 100%. The LPT correctly identified 57 of 68 food items causing delayed flares after OFC (84%). The PAX was negative for food-specific IgE in 18 of the 28 dogs (64%), as expected for delayed FA. In three dogs (11%), PAX results overlapped with those of the LPT, suggesting a mixed FA.

Conclusions and clinical relevance: Food allergies with delayed reactions after OFC-those suspected of having a cell-mediated mechanism-seemed to be the most common type of FA in the studied dogs. The LPT was helpful in identifying such cases.

Background: Antimicrobial resistance is increasing each year. For example, in 2019 it was directly responsible for an estimated >1 million deaths. Additionally, the development of new drugs is much slower, generating enormous concerns about responses to infection in the future health scenario. Therefore, probiotics have emerged as an alternative to antibiotics.

Objectives: This study aimed to isolate and identify a Lactobacillus casei from healthy canine skin and investigate its antimicrobial effect on isolates of Staphylococcus pseudintermedius originating from dogs with pyoderma.

Materials and methods: L. casei was isolated from skin samples collected with a sterile cotton swab from the inner pinnae of healthy dogs. It was then cultured, identified using matrix-assisted laser desorption ionisation time-of-flight mass spectrometry, and tested against 30 different clinical isolates and one American Type Culture Collection strain of S. pseudintermedius using the spot-on-the-lawn technique. Its safety was assessed through a modified Kirby-Bauer disc diffusion susceptibility test.

Results: L. casei inhibited the growth of all isolates of S. pseudintermedius. The mean value of the inhibition halo of all isolates was 11.3 mm. A significant positive correlation (Pearson's linear correlation = 0.444; p = 0.014) was noted between the inhibitory halos formed by L. casei on the S. pseudintermedius isolates and the halos produced by the tested antimicrobial discs on the same isolates. The L. casei strain demonstrated sensitivity to all tested antimicrobials.

Conclusions and clinical relevance: The study indicates that using commensal bacteria from canine skin, specifically L. casei, to control bacterial infections caused by S. pseudintermedius can be a promising complementary or alternative therapy to antibiotics relevant to animal and human health.