Alison Diesel

The Skin Microbiome in Healthy and Allergic Dogs

Background Changes in the microbial populations on the skin of animals have traditionally been evaluated using conventional microbiology techniques. The sequencing of bacterial 16S rRNA genes has revealed that the human skin is inhabited by a highly diverse and variable microbiome that had previously not been demonstrated by culture-based methods. The goals of this study were to describe the microbiome inhabiting different areas of the canine skin, and to compare the skin microbiome of healthy and allergic dogs. Methodology/Principal Findings DNA extracted from superficial skin swabs from healthy (n = 12) and allergic dogs (n = 6) from different regions of haired skin and mucosal surfaces were used for 454-pyrosequencing of the 16S rRNA gene. Principal coordinates analysis revealed clustering for the different skin sites across all dogs, with some mucosal sites and the perianal regions clustering separately from the haired skin sites. The rarefaction analysis revealed high individual variability between samples collected from healthy dogs and between the different skin sites. Higher species richness and microbial diversity were observed in the samples from haired skin when compared to mucosal surfaces or mucocutaneous junctions. In all examined regions, the most abundant phylum and family identified in the different regions of skin and mucosal surfaces were Proteobacteria and Oxalobacteriaceae. The skin of allergic dogs had lower species richness when compared to the healthy dogs. The allergic dogs had lower proportions of the Betaproteobacteria Ralstonia spp. when compared to the healthy dogs. Conclusions/Significance The study demonstrates that the skin of dogs is inhabited by much more rich and diverse microbial communities than previously thought using culture-based methods. Our sequence data reveal high individual variability between samples collected from different patients. Differences in species richness was also seen between healthy and allergic dogs, with allergic dogs having lower species richness when compared to healthy dogs.

What is living on your dog's skin? Characterization of the canine cutaneous mycobiota and fungal dysbiosis in canine allergic dermatitis

To characterize the skin-associated fungal microbiota (mycobiota) in dogs, and to evaluate the influence of body site, individual dog or health status on the distribution of fungi, next-generation sequencing was performed targeting the internal transcribed spacer region. A total of 10 dogs with no history of skin disease were sampled at 10 distinct body sites consisting of haired and mucosal skin, and 8 dogs with diagnosed skin allergies were sampled at six body sites commonly affected by allergic disease. Analysis of similarities revealed that body site was not an influencing factor on membership or structure of fungal communities in healthy skin; however, the mucosal sites were significantly reduced in fungal richness. The mycobiota from body sites in healthy dogs tended to be similar within a dog, which was visualized in principle coordinates analysis (PCoA) by clustering of all sites from one dog separate from other dogs. The mycobiota of allergic skin was significantly less rich than that of healthy skin, and all sites sampled clustered by health status in PCoA. Interestingly, the most abundant fungi present on canine skin, across all body sites and health statuses, were Alternaria and Cladosporium—two of the most common fungal allergens in human environmental allergies.

Serum allergen-specific immunoglobulin E in atopic and healthy cats: comparison of a rapid screening immunoassay and complete-panel analysis

Feline and canine atopic dermatitis are thought to have a similar immunopathogenesis. As with dogs, detection of allergen-specific IgE in cat serum merely supports a diagnosis of feline atopy based on compatible history, clinical signs and elimination of other pruritic dermatoses. In this study, a rapid screening immunoassay (Allercept(®) E-Screen 2nd Generation; Heska AG, Fribourg, Switzerland; ES2G) was compared with a complete-panel serum allergen-specific IgE assay (Allercept(®); Heska AG; CP) in healthy cats with no history of skin disease and in atopic cats. The latter had no diagnosis of external parasitism, infection, food hypersensitivity or other skin disease explaining their pruritus, and expressed cutaneous reaction patterns typically associated with feline allergic skin disease (head, neck or pinnal pruritus, miliary dermatitis, self-induced alopecia, eosinophilic granuloma complex). The proportion of cats positive on either the ES2G or the CP assays was not significantly different between the atopic and healthy cat groups. There was, however, strong agreement between the results of the ES2G and CP assay; overall, the two tests were in agreement for 43 of 49 (88%) serum samples. There was also strong agreement when individual allergen groups were evaluated (agreement noted: indoor, 41 of 49 samples; grasses/weeds, 37 of 49 samples; and trees, 41 of 49 samples). These results indicate that although neither test is diagnostic for feline atopic dermatitis, the screening assay is beneficial for predicting the results of a complete-panel serum allergen-specific IgE assay in cats.

The feline skin microbiota: The bacteria inhabiting the skin of healthy and allergic cats

Background The skin is inhabited by a multitude of microorganisms. An imbalance of these microorganisms is associated with disease, however, the causal relationship between skin microbiota and disease remains unknown. To describe the cutaneous bacterial microbiota of cats and determine whether bacterial dysbiosis occurs on the skin of allergic cats, the skin surfaces on various regions of 11 healthy cats and 10 allergic cats were sampled. Methodology/Principal findings Genomic DNA was extracted from skin swabs and sequenced using primers that target the V4 region of the bacterial 16S rRNA. The bacterial sequences from healthy cats revealed that there are differences in species diversity and richness between body sites and different epithelial surfaces. Bacterial communities preferred body site niches in the healthy cats, however, the bacterial communities on allergic cat skin tended to be more unique to the individual cat. Overall, the number of bacterial species was not significantly different between the two health status groups, however, the abundances of these bacterial species were different between healthy and allergic skin. Staphylococcus, in addition to other taxa, was more abundant on allergic skin. Conclusions/Significance This study reveals that there are more bacterial species inhabiting the skin of cats than previously thought and provide some evidence of an association between dysbiosis and skin disease.

Efficacy of eight commercial formulations of lime sulphur on in vitro growth inhibition of Microsporum canis

Lime sulphur is a common topical treatment for dermatophytosis in animals. Until recently, a single veterinary lime sulphur formulation was available. The purpose of this study was to compare the efficacy of eight lime sulphur products for in vitro growth inhibition of Microsporum canis using the isolated infected spore model. Infective M. canis spores were isolated from hairs collected from untreated cats. Hairs were macerated in Triton-X solution and isolated according to a previously published protocol. Equal volumes of spore suspension and lime sulphur solutions were incubated for 5 min and plated onto modified BBL™ Mycosel™ agar (Becton, Dickinson and Company; Sparks, MD, USA) plates. Five plates were inoculated for each sample solution. Distilled water and bleach were used as controls. Colony forming units were counted daily for 21 days; positive control plates contained >300 colony forming units/plate. Seven of the products were supplied as concentrates and they were tested at the manufacturers recommended dilution, twice label concentration and half label concentration. A prediluted product SulfaDip(®) (Trask Research, Inc.; Daluca, GA, USA) was tested at the label and half label concentration. All veterinary products formed recommended treatment dilutions of 3% sulphurated lime solution except one (LymDyp(®), IVX Animal Health Inc.; St Joseph, MO, USA), which formed a 2.4% sulphurated lime solution. Results of the study showed complete growth inhibition of M. canis spores by all products at all dilutions tested. These results indicate that all tested lime sulphur-containing products were equivalent. Field studies are needed to test product equivalency in vivo.

Cutaneous Hypersensitivity Dermatoses in the Feline Patient: A Review of Allergic Skin Disease in Cats

Feline allergic skin disease presents a unique set of challenges to the veterinary practitioner. Although there is some similarity to what is seen in the allergic canine patient, cutaneous hypersensitivity dermatoses in cats can manifest with strikingly different clinical signs, treatment options and outcomes, and secondary complications/disease entities. Additionally, less is known about the pathogenesis of feline allergic skin diseases, particularly “feline atopic syndrome” when compared to dogs or people. This article aims to review what is currently known in regards to allergic skin disease in the feline patient, with focus on non-flea, non-food hypersensitivity dermatitis.

Medical Management of Cyclosporine-Induced Gingival Overgrowth Using Oral Azithromycin in Six Dogs

Gingival overgrowth is an uncommon adverse effect of cyclosporine administration in veterinary species. In people, gingival overgrowth is a common complication of cyclosporine administration for immunosuppression, generally following transplant procedures. Azithromycin has been used successfully for managing gingival overgrowth in human transplant patients when cyclosporine administration cannot be reduced or discontinued. This case series describes six dogs being administered cyclosporine for various dermatologic diseases that developed gingival overgrowth. The dogs were prescribed systemic azithromycin, with or without concurrent dose reduction of cyclosporine. Oral administration of 6.6–10.8 mg/kg of azithromycin once daily for 4–14 weeks was effective for complete clinical resolution of gingival overgrowth. In most cases, gingival overgrowth did not recur even with continued cyclosporine administration long-term. Adverse events of long-term azithromycin administration did not occur in any of the dogs. This series highlights a potentially beneficial medical treatment option for gingival overgrowth even when cyclosporine dose reduction is not possible or elected, without the need for surgical resection of proliferative gingival tissue.

Equine urticaria: a clinical guide to management

Urticaria (hives) is a fairly common clinical reaction pattern in horses. Although often attributed to allergic causes, several other aetiologies can lead to the manifestation of the condition. A thorough and complete history, specifically as it relates to dermatological disease, is the practitioners most powerful tool in successful diagnosis and management. Advanced diagnostics such as allergen-specific immunoglobulin E serum or intradermal allergen tests are only helpful when an allergic aetiology has been confirmed based on appropriate history. This article discusses the various causes and appearances of urticaria in the horse, and aims to help guide the practitioner in determining when additional diagnostics and therapeutics are indicated.

What is your diagnosis? Aspirate from a digit in a cat.

A 13-year-old female spayed Domestic Shorthair cat was presented to Texas A&M University Veterinary Medical Teaching Hospital (VMTH) for a chronic nail bed infection. The owner noticed the cat favoring and holding up the left front paw about 4–6 weeks prior; no bleeding or abnormal discharge was noted. The cat was initially evaluated by the primary care veterinarian for limping, where it was noted that the nails had grown into the footpads on the 2nd and 3rd digits. The paw was also swollen and painful. The nails were trimmed and the cat was administered antibiotic and antiinflammatory injections. The cat returned to the primary care veterinarian 2 weeks later for re-evaluation, but showed no improvement. Oral antibiotics were initiated prior to referral. At presentation to the VMTH, digits 2 and 3 of the left front paw were swollen, fairly firm, and painful. Mild exudate was present along the ventral margin of the claw fold. Cytologic evaluation of the exudate surrounding the second digit on the left forelimb revealed moderate numbers of neutrophils with rare bacterial cocci. An aspirate of a lesion on the third digit of the left forelimbwas obtained (Figure 1). Figure 1. Aspirate of a lesion on the third digit on the left forelimb in a cat, Diff-Quik,9 60 objective.