Longitudinal evaluation of the cutaneous and rectal microbiota of German shepherd dogs with perianal fistulas undergoing therapy with ciclosporin and ketoconazole.

BACKGROUND: Perianal fistulas are painful ulcers or sinus tracts that disproportionately affect German shepherd dogs and are proposed as a spontaneous animal model of fistulising Crohn's disease. OBJECTIVES: To characterise the rectal and cutaneous microbiota in German shepherd dogs with perianal fistulas and to investigate longitudinal shifts with lesion resolution during immunomodulatory therapy. ANIMALS: Eleven German shepherd dogs with perianal fistulas and 15 healthy German shepherd dogs. MATERIALS AND METHODS: Affected dogs were evaluated and swabbed at three visits, 30 days apart, while undergoing treatment with ciclosporin and ketoconazole. Healthy German shepherd dogs were contemporaneously sampled. Sites included the rectum, perianal skin and axilla. The microbiome was evaluated following sequencing of the V4 hypervariable region of the 16S ribosomal RNA (rRNA) gene. RESULTS: Alpha diversity was not significantly different between healthy and affected dogs at each of the three body sites (p > 0.5), yet rectal and perianal beta diversities from affected dogs differed significantly from those of healthy dogs at Day 0 (p = 0.004). Rectal and perianal relative abundance of Prevotella spp. increased and perianal Staphylococcus spp. relative abundance decreased in affected dogs over time, coincident with lesion resolution. CONCLUSIONS AND CLINICAL RELEVANCE: Changes in lesional cutaneous and rectal microbiota occur in German shepherd dogs with perianal fistulas and shift over time with lesion resolution during immunomodulatory therapy. Further investigations of the role of cutaneous and enteric microbiota in the pathogenesis of perianal fistulas, and whether manipulation of microbial populations may ameliorate disease, are needed.

Genomic and clinical case characterisation of Staphylococcus haemolyticus isolated from dogs and cats in the United States, including strains with high-level mupirocin tolerance.

BACKGROUND: Staphylococcus haemolyticus is a coagulase-negative commensal organism of both people and companion animals. It has pathogenic potential and when cultured is often meticillin- and multidrug-resistant. OBJECTIVES: To characterise the clinical features of dogs and cats with clinical skin disease that had positive S. haemolyticus skin cultures, and to employ whole-genome sequencing (WGS) to identify resistance genes and characterise the genetic relatedness of strains. MATERIALS AND METHODS: Isolates were identified by the institutional clinical microbiology laboratory by routine aerobic culture and susceptibility from seven veterinary hospitals across the United States. Then, WGS and analysis of each isolate were performed and clinical data collected via a retrospective clinician questionnaire. RESULTS: S. haemolyticus was identified from superficial (seven of 12) and deep (five of 12) cutaneous infections in our study. Most animals had received antimicrobials (10 of 12) and/or immunomodulatory drugs (nine of 12) within the six months before culture. WGS analysis revealed a variety of genetic lineages and a wide array of antimicrobial resistance genes. Meticillin resistance was identified in nine of 12 isolates and four of 12 isolates demonstrated mupirocin tolerance. CONCLUSIONS AND CLINICAL RELEVANCE: Staphylococcus haemolyticus may be an under-recognised pathogen in companion animals, and its demonstrated potential for multidrug-resistance, meticillin-resistance, and high-level mupirocin tolerance may create a therapeutic challenge. Further studies should evaluate the prior antimicrobial use and immunocompromised status as risk factors for infection with S. haemolyticus.

Clinical and histopathological features of rostrolateral nasal alar arteriopathy of German shepherd dogs.

BACKGROUND: Dermal arteritis of the nasal philtrum (DANP) has been described in large-breed dogs. OBJECTIVES: To characterise clinically distinct, discrete fissures of the dorsolateral nasal alae associated with severe bleeding in German shepherd dogs (GSDs). ANIMALS: Fourteen privately owned GSDs with linear rostrolateral nasal alar fissures and a histopathological diagnosis of nasal vasculopathy. MATERIALS AND METHODS: Retrospective analysis of medical records and histological slides. RESULTS: Mean age of onset was 6 years. Before biopsy, episodic arteriolar bleeding was noted in 11 of the 14 (79%) dogs. Slide analysis revealed enlarged nasal arterioles with expanded vascular tunics and luminal stenosis beneath ulcers. Histopathological lesions consistent with mucocutaneous pyoderma and/or facial discoid lupus erythematosus were present in 5 of the 14 (36%) dogs. Enlarged arterioles stained blue with Alcian blue and Masson's trichrome stains, consistent with deposition of mucin and collagen, respectively. Immunohistochemical stains (neutrophil myeloperoxidase, IBA1, CD3) were performed. CD3 was negative for all dogs, whilst neutrophil myeloperoxidase and IBA1 occasionally demonstrated intramural neutrophils (3 of the 14 dogs, 21%) or histiocytes (1 of the 14 dogs, 7%) in altered vessels, respectively. All dogs underwent medical management and/or surgical excision. Treatments included tacrolimus, prednisone, ciclosporin-modified, pentoxifylline, antimicrobials and doxycycline/niacinamide. No dogs were treated with antimicrobials alone. For seven dogs with long-term follow-up, treatment response was complete in five (71%) and partial in two (29%), with six of the seven (86%) receiving immunomodulatory treatments to maintain remission. CONCLUSION AND CLINICAL RELEVANCE: Nasal alar arteriopathy of GSDs shares histopathological changes with DANP. It has characteristic clinical and histopathological features and appears amenable to immunomodulation.

Interobserver reliability of Feline Dermatitis Extent and Severity Index (FEDESI) and Scoring Feline Allergic Dermatitis (SCORFAD) and the relationship between lesion scores and pruritus.

BACKGROUND: Feline Dermatitis Extent and Severity Index (FEDESI) and Scoring Feline Allergic Dermatitis (SCORFAD) are scales used to assess lesion severity in cats with allergic dermatitis. Interobserver reliability has not been assessed for either. HYPOTHESIS AND OBJECTIVES: To determine interobserver reliability for FEDESI and SCORFAD, and the relationship between lesion scores and pruritus. ANIMALS: Thirty-eight cats presenting for pruritus. METHODS AND MATERIALS: Each cat's lesions were scored by two observers at each visit using both FEDESI and SCORFAD (n = 117 paired observations). Spearman's rho was calculated to assess correlation between scales and between each scale and the owner-reported pruritus Visual Analog Scale (pVAS). Concordance correlation coefficients were calculated between observers for each scale, and Bland-Altman plots were used to visually represent the relationship between paired scores. RESULTS: FEDESI and SCORFAD were strongly positively correlated with one another (rho = 0.84, P < 0.001). Each scale showed fair correlation with pVAS (rho = 0.42, P < 0.001; rho = 0.38, P < 0.001, respectively). There was good concordance between observers for both scales, with a correlation coefficient of 0.77 for FEDESI and 0.80 for SCORFAD [intraclass correlation coefficient (ICC) 95%, confidence interval (CI) 0.69-0.83; ICC 95%, CI 0.72-0.86, respectively]. Median lesion score was low (FEDESI 20; SCORFAD 4), which may improve interobserver reliability. CONCLUSIONS AND CLINICAL IMPORTANCE: There is good interobserver reliability for both FEDESI and SCORFAD. FEDESI and SCORFAD are positively correlated with one another and with pVAS. These findings support use of both scales in clinical research and assessment.

Multivariable analysis of the influence of cross-reactive carbohydrate determinant inhibition and other factors on intradermal and serological allergen test results: a prospective, multicentre study.

BACKGROUND: Serological allergen testing (SAT) is used widely to formulate allergen-specific immunotherapy for atopic dogs. Serum immunoglobulin (Ig)E specific for cross-reactive carbohydrate determinants (CCD) can produce false-positive reactions, creating discrepancy between SAT and intradermal allergen test (IDAT) results. OBJECTIVES: The primary objective was to determine if inhibition of anti-CCD IgE in a commercial assay improved correlation with IDAT. The secondary objective was to assess the influence of dog- and clinic-specific factors, environmental factors, putative allergen exposure and prior medications on intradermal and SAT reactivity. ANIMALS: Two-hundred and eleven client-owned dogs were enrolled from eight North American dermatology specialty practices. METHODS AND MATERIALS: Collection of serum samples and IDAT were performed on the same day. Sera were assayed for detection of IgE specific to 25 allergens, before and after treatment with a proprietary inhibitor of anti-CCD IgE. Data for each dog were collected via a questionnaire filled out by veterinary personnel. RESULTS: The correlation between the testing modalities was fair before (Spearman's rho, ρ = 0.2092) and after (ρ = 0.3042) inhibition of anti-CCD IgE. Ciclosporin dose (P = 0.003), independent of duration of use, and duration of lokivetmab use (P = 0.001), independent of dose administered, were associated with statistically significant decreases in IgE concentrations across all allergen types. CONCLUSIONS AND CLINICAL RELEVANCE: Contrary to previous reports, this study demonstrated unchanged correlation between SAT and IDAT after inhibition of anti-CCD IgE. Ciclosporin dose and lokivetmab treatment duration may have unexplored effects on IgE concentration during SAT.

The otic microbiota and mycobiota in a referral population of dogs in eastern USA with otitis externa.

BACKGROUND: Canine otitis externa (OE) is a common inflammatory disease that is frequently complicated by secondary bacterial and/or yeast infections. The otic microbial population is more complex than appreciated by cytological methods and aerobic culture alone. HYPOTHESIS/OBJECTIVES: Differences in bacterial and fungal populations of the external ear canal will correlate with specific cytological and culture-based definitions of bacterial and Malassezia otitis. ANIMALS: Forty client-owned dogs; 30 with OE and 10 with healthy ears. METHODS AND MATERIALS: Prospective study comparing cytological samples, aerobic bacterial cultures and culture-independent sequencing-based analyses of the external ear canal. Subjects with OE included 10 dogs with only cocci [≥25/high power field (HPF)] on cytological evaluation and culture of Staphylococcus spp.; 10 dogs with rods (≥25/HPF) and exclusive culture of Pseudomonas aeruginosa; 10 dogs with only yeast on cytological results morphologically compatible with Malassezia spp. (≥5/HPF). RESULTS: Staphylococcus was the most abundant taxa across all groups. Ears cytologically positive for cocci had decreased diversity, and all types of OE were associated with decreased fungal diversity compared to controls. CONCLUSIONS AND CLINICAL IMPORTANCE: Cytological and culture-based assessment of the ear canal is not predictive of the diverse microbiota of the ear canal in cases of Pseudomonas or Malassezia otitis. Less abundant bacterial taxa in cases of staphylococcal OE are worth scrutiny for future biological therapy.

Discriminatory features of acute eosinophilic dermatitis with oedema (Wells-like syndrome) and sterile neutrophilic dermatosis (Sweet's-like syndrome) in dogs.

BACKGROUND: Canine acute eosinophilic dermatitis with oedema (CAEDE) and sterile neutrophilic dermatosis have overlapping clinical and histopathological features. HYPOTHESIS/OBJECTIVES: The objective of this study was to identify features that differentiate these entities. ANIMALS: Forty dogs. METHODS AND MATERIALS: Retrospective case series. Forty cases with diagnoses of either CAEDE and/or sterile neutrophilic dermatosis were included based on histopathological review. Medical records (29 of 40 dogs) were reviewed for clinical findings and historical data. Commercially available immunohistochemical stains for granulocytes and a Luna stain were performed (40 of 40 dogs) to assess the granulocytic infiltrate. RESULTS: Nineteen cases had been previously diagnosed as CAEDE, seven cases had been designated as sterile neutrophilic dermatosis and 14 cases had overlapping features. Based on review and receiver operating characteristic (ROC) curve analysis, 30 cases with >12% eosinophils, enumerated by Luna staining, were diagnosed as eosinophilic dermatitis and oedema. Ten cases were diagnosed as sterile neutrophilic dermatosis. Dogs with CAEDE frequently had gastrointestinal signs (24 of 30;80%) and pruritus (11 of 30;33%). In dogs with sterile neutrophilic dermatosis, five of 10 (50%) had diagnoses of or histories compatible with immune-mediated polyarthropathy. CONCLUSIONS AND CLINICAL IMPORTANCE: In this case series, CAEDE was encountered more frequently than neutrophilic dermatosis and could be distinguished by the eosinophilic infiltrate, aided by a Luna stain. Concurrent arthralgia was more frequently identified with neutrophilic dermatosis. It remains unclear whether CAEDE and sterile neutrophilic dermatosis are separate disease entities or varied manifestations of the same disease.

Canine ischaemic dermatopathy: a retrospective study of 177 cases (2005-2016).

BACKGROUND: Ischaemic dermatopathy encompasses a poorly understood subset of canine diseases that share similar clinical and histological features. Very little information is currently available regarding population characteristics, progression and outcome. HYPOTHESIS/OBJECTIVES: This study aimed to describe the clinical features and therapeutic outcomes of ischaemia dermatopathy, excluding familial dermatomyositis, using cases diagnosed by histopathological analysis. ANIMALS: One hundred and seventy-seven cases submitted for histopathological analysis between 2005 and 2016 met inclusion criteria, of which 93 had complete medical records available. METHODS AND MATERIALS: Both records and pointed surveys were used to retrieve information. Scoring systems were created to subjectively evaluate clinical outcomes and likelihood of a vaccine association. RESULTS: Of 177 cases, toy and miniature poodles, Chihuahuas, Maltese, Yorkshire terriers and Jack Russell terriers were significantly over-represented (P < 0.001). Of the 93 cases for which historical data were obtained, median age at skin biopsy was five years (0.42-13 years) and median body weight was 7.3 kg (range 1.32-50.3 kg). The condition in 45 dogs (48.3%) was found likely to be associated with vaccination. Younger ages (P = 0.011) and higher body weights (P = 0.003) were positively correlated with greater likelihood of vaccination. Body weight <10 kg (P = 0.0045) and older ages (P = 0.0048) were significantly associated with worse outcomes. CONCLUSIONS AND CLINICAL IMPORTANCE: This study provides support for breed predispositions and identifies potential prognostic factors. Importantly, over half of the cases were considered unlikely to be vaccine-associated, demonstrating the need to investigate other underlying causes of this condition.

Clinical and histopathological features of Burkholderia cepacia complex dermatitis in dogs: a series of four cases.

BACKGROUND: The Burkholderia cepacia complex (Bcc) is an emerging cause of opportunistic infections. Deep pyoderma associated with Bcc infection has been reported previously in dogs receiving ciclosporin. OBJECTIVE: To report the clinical and histopathological features of four additional cases of Bcc dermatitis in dogs, one of which progressed to septicaemia. ANIMALS: Four dogs with a skin culture yielding growth of Bcc and skin biopsies for histopathological investigation. METHODS AND MATERIALS: Retrospective review of medical records and skin biopsies and PCR for Burkholderia on DNA extracted from paraffin-embedded skin and liver to confirm Bcc sepsis. RESULTS: Three different breeds and one mixed breed dog were represented. Two dogs were receiving ciclosporin and one was receiving oclacitinib. One dog had no evidence of immunosuppression. One dog was bathed two days prior to onset of skin lesions. Three dogs presented with dorsally orientated ulcers, crusts and draining tracts; one dog had infection localized to a surgical site. The main histological feature from skin biopsies was severe neutrophilic folliculitis and furunculosis with marked neutrophilic to pyogranulomatous dermatitis. Intracellular Gram-negative and Warthin-Starry positive rods were present in three of four cases. Three dogs were successfully treated with systemic fluoroquinolones or trimethoprim sulfamethoxazole. The Bcc isolate in one dog was resistant to all tested systemic antimicrobials. This dog developed septicaemia and was euthanized. CONCLUSIONS AND CLINICAL IMPORTANCE: Bcc skin infections can occur in immunocompetent and immunocompromised dogs. Bcc isolates may be extensively antimicrobial resistant, presenting a challenge for clinical management. Cutaneous infection may progress to life-threatening sepsis.

Localized parakeratotic hyperkeratosis in sixteen Boston terrier dogs.

BACKGROUND: Although zinc responsive dermatosis is typically a disorder of Arctic breed dogs, this study identifies similar cutaneous lesions on the face and pressure points of Boston terrier dogs. HYPOTHESIS/OBJECTIVES: To document the clinical and histological features of localized parakeratotic hyperkeratosis of Boston terrier dogs, to determine if the lesions respond to zinc supplementation and to determine whether tissue zinc levels were decreased in affected versus unaffected dogs. MATERIAL AND METHODS: Sixteen Boston terrier dogs with similar gross and histological findings were identified retrospectively from two institutions. Follow-up information for nine dogs from one institution was obtained from referring veterinarians using a questionnaire. Tissue zinc levels were measured from formalin-fixed paraffin-embedded skin biopsy samples of affected and unaffected dogs using inductively coupled plasma mass spectrometry. RESULTS: Mild to severe parakeratotic hyperkeratosis with follicular involvement was present in all 16 cases. Of the nine dogs for which follow-up information was available, five dogs received oral zinc supplementation and four dogs had documented clinical improvement or resolution of dermatological lesions. The median skin zinc levels were not significantly different between affected and unaffected dogs. CONCLUSIONS AND CLINICAL IMPORTANCE: To the best of the authors' knowledge this is the first report of localized parakeratotic hyperkeratosis in Boston terrier dogs, some of which improved with oral zinc supplementation. Prospective studies in Boston terrier dogs are warranted to document potential zinc deficiency (serum and/or tissue levels, pre- and post-treatment) and to objectively assess response to zinc supplementation and other therapies.

Genotypic relatedness and antimicrobial resistance of Staphylococcus schleiferi in clinical samples from dogs in different geographic regions of the United States.

BACKGROUND: Staphylococcus schleiferi is a known pathogen that can cause canine skin and ear infections. The aim of this study was to determine the molecular epidemiology and antimicrobial susceptibility of clinical veterinary isolates from different geographic regions in the United States. HYPOTHESIS: It was hypothesized that S. schleiferi would maintain genotypic homogeneity across the different geographic regions and that meticillin-resistant (MR) isolates of S. schleiferi would predominate. METHODS: Isolates were identified as S. schleiferi by a commercial microbiology identification system and confirmed by nuc gene PCR. Antibiotic susceptibility data were collected and PBP2a latex agglutination testing was performed on MR isolates. Pulsed-field gel electrophoresis (PFGE) was performed and clonal clusters were identified with a Dice coefficient similarity of >80%. RESULTS: There were 116 isolates from the Mid-Atlantic region and 101 from across the United States. Of these 217 isolates, 209 (96%) were obtained from cutaneous sites. Of the Mid-Atlantic isolates, 62% (72 of 116) were MR and 16% (18 of 116) were multidrug-resistant (MDR). Of the isolates from the other geographic regions, 73% (74 of 101) were MR and 24% (24 of 101) were MDR. All MR isolates were positive by PBP2a latex agglutination. PFGE identified 155 individual pulsed-field profiles and three major pulsed-field types (PFT) that contained 61% (133 of 217) of the isolates. These pulsed-field types were geographically heterogeneous. CONCLUSIONS: This study demonstrates the dissemination of successful MR pulsed-field types of S. schleiferi across the United States.

Effects of butorphanol versus dexmedetomidine sedation on intradermal allergen and histamine responses in dogs with atopic dermatitis.

BACKGROUND: Sedation is commonly used during intradermal testing (IDT). Morphine and its derivatives have long been avoided because of their histamine-releasing effects. HYPOTHESIS/OBJECTIVES: Butorphanol, an opioid agonist/antagonist, will not adversely affect IDT in dogs. ANIMALS: Ten client-owned dogs diagnosed with atopic dermatitis. METHODS: Dogs were randomized to be sedated with butorphanol (0.4 mg/kg) or dexmedetomidine (5 µg/kg). Routine IDT along with intradermal injections of various dilutions of histamine were performed on the lateral thorax, followed 7 days later by the alternative sedative and IDT on the opposite side. The injection sites were subjectively scored and objectively measured by one investigator, blinded to the sedatives, and compared between groups. RESULTS: When the mean wheal diameters from the objective measurements of all antigens, including saline and histamine dilutions, were compared, butorphanol was associated with significantly smaller reactions than dexmedetomidine (P = 0.0001). There was a high level of agreement between sedatives when positive reactions subjectively scored as ≥3+ were compared (κ = 0.91). When mean wheal diameters of histamine at concentrations of 1:100,000, 1:400,000, 1:1,600,000 and 1:6,400,000 were compared, there were no significant differences between sedative types. Moreover, the percentage agreement when comparing subjective interpretation of all histamine dilutions between sedations was high (κ = 0.90). However, there was only 69% agreement beyond chance when objective and subjective interpretations of all antigens were compared between sedative groups. CONCLUSIONS: Although butorphanol resulted in significantly smaller wheal size in comparison to dexmedetomidine, it did not affect the overall subjective interpretation of the results of IDT.

Treatment outcome of dogs with meticillin-resistant and meticillin-susceptible Staphylococcus pseudintermedius pyoderma.

BACKGROUND: The prevalence of meticillin- and multidrug-resistant Staphylococcus pseudintermedius (MRSP) in canine pyoderma has been increasing in recent years; thus, treatment of these cases has become challenging. HYPOTHESIS/OBJECTIVES: To compare treatment outcome (clinical resolution and treatment duration), adverse effects of medication, and concurrent diseases and medications in dogs with meticillin-susceptible S. pseudintermedius (MSSP) and MRSP pyoderma. ANIMALS/METHODS: Medical records were reviewed retrospectively, and 123 MSSP and 93 MRSP clinical cases between January 2008 and April 2010 were included. RESULTS: In MSSP infections, cefalexin and cefpodoxime were the most commonly prescribed antimicrobials, accounting for 43.2 and 34.4% of cases, respectively. In MRSP infections, chloramphenicol and doxycycline were most commonly prescribed, accounting for 52.6 and 14.4% of cases, respectively. Adverse effects were reported in seven MSSP and 31 MRSP cases. The most commonly reported adverse effects were gastrointestinal, prompting antibiotic discontinuation in three MSSP and 20 MRSP cases. Chloramphenicol was associated with the highest incidence of adverse reactions (27 of 51 cases). Of 164 cases with follow up, 43 of 88 MSSP infections and 29 of 76 MRSP infections achieved complete clinical resolution at the first recheck examination. Three MSSP and seven MRSP cases failed to improve or resolve at subsequent visits assessed at 3-4 week intervals. CONCLUSIONS AND CLINICAL IMPORTANCE: Results from this study showed that the majority of pyodermas resolved regardless of meticillin susceptibility. Although some cases of MRSP pyoderma took longer to treat, this is likely to be because of chronicity and not the organism. In addition, adverse effects were frequently associated with chloramphenicol administration.

Genotypic relatedness and phenotypic characterization of Staphylococcus schleiferi subspecies in clinical samples from dogs.

OBJECTIVE: To assess the degree of biological similarity (on the basis of genotype determined via pulsed-field gel electrophoresis [PFGE]) between isolates of 2 Staphylococcus schleiferi subspecies (S schleiferi subsp coagulans and S schleiferi subsp schleiferi) in clinical samples obtained from dogs. SAMPLE POPULATION: 161 S schleiferi isolates from 160 canine patients. PROCEDURES: A commercial microbiology identification system was used to identify each isolate as S schleiferi. Isolates underwent slide and tube coagulase testing and antimicrobial susceptibility testing. A mecA PCR assay and a latex agglutination test for penicillin-binding protein 2a (PBP2a) were also performed on each isolate. Clonal clusters with a similarity cutoff value of 80% were identified via PFGE. RESULTS: Of the 161 isolates, 61 (38%), 79 (49%), and 21 (13%) were obtained from cutaneous sites, ears, and other sites, respectively; 110 (68%) were coagulase negative, and 51 (32%) were coagulase positive. Among the coagulase-negative and coagulase-positive isolates, 65% (71/110) and 39% (20/51) were oxacillin resistant, respectively. All oxacillin-resistant isolates yielded positive results via mecA PCR assay and PBP2a latex agglutination testing. Via PFGE, 15 major clusters and 108 individual pulsed-field profiles were identified. Oxacillin-resistant and oxacillin-susceptible isolates clustered separately. Clonal clusters were heterogeneous and contained representatives of both subspecies. CONCLUSIONS AND CLINICAL RELEVANCE: Coagulase-positive and coagulase-negative isolates were not genotypically distinct and may represent a single S schleiferi sp with variable coagulase production, rather than 2 biologically distinct subspecies. Further studies are needed to characterize clinical or epidemiological differences associated with infections with coagulase-positive and coagulase-negative S schleiferi in dogs.

Canine Perianal Fistulas: Clinical Presentation, Pathogenesis, and Management.

Canine perianal fistulas are painful sinus tracts and ulcers that spontaneously develop in the skin around the anus. Middle-aged German shepherd dogs are most commonly affected and may have a genetic susceptibility. Although the disease was once believed related to conformational factors and primarily managed surgically, an immune-mediated pathogenesis is now recognized. Long-term medical management with immunomodulatory agents has become standard of care for canine perianal fistulas. Perianal fistulas can be debilitating and have a negative impact on quality of life of dogs and owners. Accurate diagnosis and aggressive medical therapy are key to successful management of canine perianal fistulas.

Clinical and histologic features of acute-onset erythroderma in dogs with gastrointestinal disease: 18 cases (2005-2015).

OBJECTIVE To describe the clinical and histologic features of acute erythroderma in dogs with gastrointestinal disease. DESIGN Retrospective case series. ANIMALS 18 dogs with erythroderma and gastrointestinal disease. PROCEDURES Medical records and biopsy specimens were reviewed. Information collected from medical records included signalment, clinical signs, physical examination and diagnostic test results, treatment, and outcome. The Naranjo algorithm was used to estimate the probability of an adverse drug reaction for each dog. RESULTS All dogs had an acute onset of erythematous macules or generalized erythroderma. Histologic features of skin biopsy specimens had 3 patterns representing a progressive spectrum of inflammation. Most dogs had vomiting (n = 17) and hematochezia (10). Signs of gastrointestinal disease became evident before, after, or concurrent with the onset of skin lesions in 10, 3, and 5 dogs, respectively. Inflammatory bowel disease, pancreatitis, and adverse food reaction were diagnosed in 5, 3, and 3 dogs, respectively. The cause of the gastrointestinal signs was not identified for 8 dogs. Eight dogs had a Naranjo score consistent with a possible adverse drug reaction. Treatment of skin lesions included drug withdrawal (n = 15), antihistamines (16), and corticosteroids (14). Signs of gastrointestinal disease and skin lesions resolved at a mean of 4.6 days and 20.8 days, respectively, after onset. CONCLUSIONS AND CLINICAL RELEVANCE Results indicated acute erythroderma may be associated with > 1 gastrointestinal disease or an adverse drug reaction in some dogs. Recognition of the clinical and histologic features of this syndrome is essential for accurate diagnosis.

Divergent Isoprenoid Biosynthesis Pathways in Staphylococcus Species Constitute a Drug Target for Treating Infections in Companion Animals.

Staphylococcus species are a leading cause of skin and soft tissue infections in humans and animals, and the antibiotics used to treat these infections are often the same. Methicillin- and multidrug-resistant staphylococcal infections are becoming more common in human and veterinary medicine. From a "One Health" perspective, this overlap in antibiotic use and resistance raises concerns over the potential spread of antibiotic resistance genes. Whole-genome sequencing and comparative genomics analysis revealed that Staphylococcus species use divergent pathways to synthesize isoprenoids. Species frequently associated with skin and soft tissue infections in companion animals, including S. schleiferi and S. pseudintermedius, use the nonmevalonate pathway. In contrast, S. aureus, S. epidermidis, and S. lugdunensis use the mevalonate pathway. The antibiotic fosmidomycin, an inhibitor of the nonmevalonate pathway, was effective in killing canine clinical staphylococcal isolates but had no effect on the growth or survival of S. aureus and S. epidermidis. These data identify an essential metabolic pathway in Staphylococcus that differs among members of this genus and suggest that drugs such as fosmidomycin, which targets enzymes in the nonmevalonate pathway, may be an effective treatment for certain staphylococcal infections. IMPORTANCE Drug-resistant Staphylococcus species are a major concern in human and veterinary medicine. There is a need for new antibiotics that exhibit a selective effect in treating infections in companion and livestock animals and that would not be used to treat human bacterial infections. We have identified fosmidomycin as an antibiotic that selectively targets certain Staphylococcus species that are often encountered in skin infections in cats and dogs. These findings expand our understanding of Staphylococcus evolution and may have direct implications for treating staphylococcal infections in veterinary medicine.

Longitudinal Evaluation of the Skin Microbiome and Association with Microenvironment and Treatment in Canine Atopic Dermatitis.

Host-microbe interactions may play a fundamental role in the pathogenesis of atopic dermatitis, a chronic relapsing inflammatory skin disorder characterized by universal colonization with Staphylococcus species. To examine the relationship between epidermal barrier function and the cutaneous microbiota in atopic dermatitis, this study used a spontaneous model of canine atopic dermatitis. In a cohort of 14 dogs with canine atopic dermatitis, the skin microbiota were longitudinally evaluated with parallel assessment of skin barrier function at disease flare, during antimicrobial therapy, and post-therapy. Sequencing of the bacterial 16S ribosomal RNA gene showed decreased bacterial diversity and increased proportions of Staphylococcus (S. pseudintermedius in particular) and Corynebacterium species compared with a cohort of healthy control dogs (n = 16). Treatment restored bacterial diversity with decreased proportions of Staphylococcus species, concurrent with decreased canine atopic dermatitis severity. Skin barrier function, as measured by corneometry, pH, and transepidermal water loss also normalized with treatment. Bacterial diversity correlated with transepidermal water loss and pH level but not with corneometry results. These findings provide insights into the relationship between the cutaneous microbiome and skin barrier function in atopic dermatitis, show the impact of antimicrobial therapy on the skin microbiome, and highlight the utility of canine atopic dermatitis as a spontaneous nonrodent model of atopic dermatitis.

Clinical and histopathologic features of dorsally located furunculosis in dogs following water immersion or exposure to grooming products: 22 cases (2005-2013).

OBJECTIVE: To describe clinical and histopathologic features of furunculosis in dogs following water immersion or exposure to grooming products. DESIGN: Retrospective case series. ANIMALS: 22 dogs with skin lesions consistent with furunculosis and a history of water immersion or grooming prior to onset. Procedures-Information collected from the medical records of affected dogs included signalment, clinical signs, bathing or grooming procedure, diagnostic tests, treatment, and outcome. RESULTS: German Shepherd Dogs (4/22 [18%]) and Labrador Retrievers (4/22 [18%]) were most commonly affected. Skin lesions, particularly hemorrhagic pustules and crusts, were dorsally located in all dogs and occurred a median of 2 days (range, 1 to 7 days) following water immersion or exposure to grooming products. Twenty (91%) dogs were bathed at home or at a commercial grooming facility prior to lesion onset; 1 dog developed skin lesions following hydrotherapy on an underwater treadmill, and 1 dog developed peri-incisional skin lesions after surgery. Lethargy, signs of neck or back pain, and fever were common clinical signs. Pseudomonas aeruginosa was the most common bacterial isolate from dogs with bacteriologic culture performed on skin samples (10/14). The main histologic feature was acute follicular rupture in the superficial dermis with suppurative inflammation and dermal hemorrhage. Systemic antimicrobial treatment, particularly oral administration of fluoroquinolones, resulted in excellent clinical response in 16 of 22 (73%) dogs. CONCLUSIONS AND CLINICAL RELEVANCE: Acute-onset furunculosis with characteristic clinical and histopathologic features in dogs following water immersion or exposure to grooming products was described. Knowledge of the historical and clinical features of this syndrome is essential for accurate diagnosis and appropriate treatment of affected dogs.

Complete Genome Sequence and Methylome of Staphylococcus schleiferi, an Important Cause of Skin and Ear Infections in Veterinary Medicine.

Staphylococcus schleiferi, a Gram-positive and coagulase-variable organism, is an opportunistic human pathogen and a major cause of skin and soft tissue infections in dogs. Here, we report the first S. schleiferi genome sequence and methylome from four canine clinical isolates.