An ancient haplotype containing antimicrobial peptide gene variants is associated with severe fungal skin disease in Persian cats.

Dermatophytosis, also known as ringworm, is a contagious fungal skin disease affecting humans and animals worldwide. Persian cats exhibit severe forms of the disease more commonly than other breeds of cat, including other long-haired breeds. Certain types of severe dermatophytosis in humans are reportedly caused by monogenic inborn errors of immunity. The goal of this study was to identify genetic variants in Persian cats contributing to the phenotype of severe dermatophytosis. Whole-genome sequencing of case and control Persian cats followed by a genome-wide association study identified a highly divergent, disease-associated haplotype on chromosome F1 containing the S100 family of genes. S100 calcium binding protein A9 (S100A9), which encodes a subunit of the antimicrobial heterodimer known as calprotectin, contained 13 nonsynonymous variants between cases and controls. Evolutionary analysis of S100A9 haplotypes comparing cases, controls, and wild felids suggested the divergent disease-associated haplotype was likely introgressed into the domestic cat lineage and maintained via balancing selection. We demonstrated marked upregulation of calprotectin expression in the feline epidermis during dermatophytosis, suggesting involvement in disease pathogenesis. Given this divergent allele has been maintained in domestic cat and wildcat populations, this haplotype may have beneficial effects against other pathogens. The pathogen specificity of this altered protein should be investigated before attempting to reduce the allele frequency in the Persian cat breed. Further work is needed to clarify if severe Persian dermatophytosis is a monogenic disease or if hidden disease-susceptibility loci remain to be discovered. Consideration should be given to engineering antimicrobial peptides such as calprotectin for topical treatment of dermatophytosis in humans and animals.

Gastrointestinal tract pathology of the owl monkey (Aotus spp.).

Owl monkeys are small nocturnal new world primates in the genus Aotus that are most used in biomedical research for malaria. Cardiomyopathy and nephropathy are well-described common diseases contributing to their morbidity and mortality; less is known about lesions affecting the gastrointestinal tract. Records from a 14-year period (2008-2022) at the Keeling Center for Comparative Medicine and Research were queried to identify instances of spontaneous gastrointestinal disease that directly contributed to the cause of death from the 235 adult owl monkeys submitted for necropsy. Of the 235, 10.6% (25/235) had gastrointestinal disease listed as a significant factor that contributed to morbidity and mortality. Diagnoses included candidiasis (3/25), gastric bloat (4/25), and intestinal incarceration and ischemia secondary (11/25), which included intussusception (4/25), mesenteric rent (3/25), strangulating lipoma (2/25), intestinal torsion (1/25), and an inguinal hernia (1/25). Intestinal adenocarcinomas affecting the jejunum (4/25) were the most common neoplasia diagnosis. Oral squamous cell carcinoma (1/25) and intestinal lymphoma (2/25) were also diagnosed. This report provides evidence of spontaneous lesions in the species that contribute to morbidity and mortality.

Considerations for performing companion animal skin microbiome studies.

The microbiome field has grown significantly in the past decade, and published studies have provided an overview of the microorganisms inhabiting the skin of companion animals. With the continued growth and interest in this field, concerns have been raised regarding sample collection methods, reagent contamination, data processing and environmental factors that may impair data interpretation (especially as related to low-biomass skin samples). In order to assure transparency, it is important to report all steps from sample collection to data analysis, including use of proper controls, and to make sequence data and sample metadata publicly available. Whilst interstudy variation will continue to exist, efforts to standardise methods will reduce confounding variables, and allow for reproducibility and comparability of results between studies. Companion animal microbiome studies often include clinical cases, and small sample sizes may result in lack of statistical significance within small datasets. The ability to combine results from standardised studies through meta-analyses would mitigate the limitations of these smaller studies, providing for more robust interpretation of results which could then inform clinical decisions. In this narrative review, we aim to present considerations for designing a study to evaluate the skin microbiome of companion animals, from conception to data analysis.

Le domaine du microbiome s'est considérablement développé au cours de la dernière décennie, et les études publiées fournisse une vue d'ensemble des micro­organismes présents sur la peau des animaux de compagnie. Avec la croissance continue et l'intérêt concernant ce domaine, des interrogations ont été soulevées concernant les méthodes de collecte des échantillons, la contamination des réactifs, le traitement des données et les facteurs environnementaux qui peuvent nuire à l'interprétation des données (en particulier en ce qui concerne les échantillons de peau à faible biomasse). Dans un souci de transparence, il est important de rendre compte de toutes les étapes, de la collecte des échantillons à l'analyse des données, y compris l'utilisation de contrôles appropriés, et de rendre les données séquentielles et les métadonnées des échantillons accessibles au public. Même s'il y existe toujours des variations entre les études, les efforts de normalisation des méthodes réduiront les variables confusionnelles et permettront la reproductibilité et la comparabilité des résultats entre les études. Les études sur le microbiome des animaux de compagnie incluent souvent des cas cliniques, et la petite taille des échantillons peut entraîner un manque de signification statistique dans les petits ensembles de données. La possibilité de combiner les résultats d'études standardisées par le biais de méta­analyses atténuerait les limites de ces petites études et permettrait une interprétation plus solide des résultats, qui pourrait alors éclairer les décisions cliniques. Dans cette revue narrative, nous visons à présenter les considérations relatives à la conception d'une étude destinée à évaluer le microbiome cutané des animaux de compagnie, depuis la conception jusqu'à l'analyse des données.

A área dos estudos do microbioma cresceu significativamente na última década e trabalhos publicados forneceram uma visão geral dos microrganismos que habitam a pele de animais de companhia. Com crescimento do interesse neste campo, surgiram preocupações em relação aos métodos de coleta de amostras, contaminação de reagentes, processamento de dados e fatores ambientais que podem prejudicar a interpretação dos dados (especialmente no que diz respeito a amostras de pele com baixa biomassa). Para garantir a transparência, é importante relatar todas as etapas desde a coleta da amostra até a análise dos dados, incluindo o uso de controles adequados, e disponibilizar publicamente os dados da sequência e os metadados da amostra. Embora a variação entre estudos continue a existir, os esforços para padronizar os métodos reduzirão as variáveis de confusão e permitirão a reprodutibilidade e a comparabilidade dos resultados entre os estudos. Os estudos de microbioma de animais de companhia geralmente incluem casos clínicos, e amostras pequenas podem resultar na ausência de significância estatística em bases de dados pequenas. A capacidade de combinar resultados de estudos padronizados através de meta­análises reduziria as limitações destes estudos menores, proporcionando uma interpretação mais robusta dos resultados que poderiam então influenciar as condutas clínicas. Nesta revisão narrativa, pretendemos apresentar considerações para o delineamento de estudos de microbioma cutâneo de animais de companhia, desde a concepção até a análise dos dados.

El campo del microbioma ha crecido significativamente en la última década y los estudios publicados han proporcionado una visión general de los microorganismos que habitan en la piel de los animales de compañía. Con el continuo crecimiento e interés en este campo, han surgido preocupaciones con respecto a los métodos de recolección de muestras, la contaminación de los reactivos, el procesamiento de datos y los factores ambientales que pueden afectar la interpretación de los datos (especialmente en relación con las muestras de piel de baja biomasa). Para garantizar la transparencia, es importante informar todos los pasos desde la recolección de muestras hasta el análisis de datos, incluido el uso de controles adecuados, y hacer que los datos de secuencia y los metadatos de muestras estén disponibles públicamente. Si bien seguirá existiendo variación entre estudios, los esfuerzos para estandarizar los métodos reducirán las variables de confusión y permitirán la reproducibilidad y comparabilidad de los resultados entre los estudios. Los estudios del microbioma de animales de compañía a menudo incluyen casos clínicos, y los tamaños de muestra pequeños pueden resultar en una falta de significancia estadística dentro de conjuntos de datos pequeños. La capacidad de combinar resultados de estudios estandarizados a través de metanálisis mitigaría las limitaciones de estos estudios más pequeños, proporcionando una interpretación más sólida de los resultados que luego podría informar las decisiones clínicas. En esta revisión narrativa, nuestro objetivo es presentar consideraciones para diseñar un estudio para evaluar el microbioma de la piel de animales de compañía, desde la concepción hasta el análisis de los datos.

Common superficial and deep cutaneous bacterial infections in domestic animals: A review.

The skin covers the external surface of animals, and it is constantly exposed to and inhabited by different microorganisms, including bacteria. Alterations in the skin barrier allow commensal and/or pathogenic bacteria to proliferate and penetrate deep into the lower layers of the skin. Being the first barrier to the external environment, the skin is prone to injuries, allowing the penetration of microorganisms that may lead to severe deep infections. Companion animals, especially dogs, are prone to bacterial infections, often secondary to allergic dermatitis. When environmental conditions are unfavorable, horses, cattle, sheep, and goats can develop superficial infections, such as those caused by Dermatophilus congolensis. Deep inflammation is commonly caused by Mycobacterium spp., which results in granulomatous to pyogranulomatous dermatitis and panniculitis. Likewise, bacteria such as Nocardia spp. and Actinomyces spp. can cause deep pyogranulomatous inflammation. Bacteria that lead to deep necrotizing lesions (eg, necrotizing fasciitis/flesh-eating bacteria) can be severe and even result in death. This review includes an overview of the most common cutaneous bacterial infections of domestic animals, highlighting the main features and histologic morphology of the bacteria, cutaneous structures involved, and the type of inflammatory infiltrates.

Hyphae, pseudohyphae, yeasts, spherules, spores, and more: A review on the morphology and pathology of fungal and oomycete infections in the skin of domestic animals.

Fungi are among the most common infectious agents affecting the skin of animals. The skin can serve as a port of entry for fungal infections, which can eventually become disseminated. In some regions of the world, oomycetes, such as Pythium and Lagenidium, are also responsible for a significant number of severe cutaneous infections. Histologic evaluation of fungal morphology, including size, shape, septation, branching, and budding characteristics, combined with the distribution of inflammatory infiltrates within different skin layers can potentially identify etiologic agents, guiding selection of antifungals and additional diagnostics. Fungal infections of the skin surface are typically caused by Malassezia and rarely Candida, with opportunistic fungi also capable of colonizing the skin surface, especially when the barrier is broken. Folliculocentric infections, caused by dermatophytes, result in mild to severe inflammation and can occasionally penetrate deep into the skin. A wide range of fungi, including agents of hyalohyphomycosis, phaeohyphomycosis, and dimorphic fungal infections, as well as oomycetes, result in nodular cutaneous and subcutaneous lesions. With the occasional exception of dimorphic fungi, fungal speciation often requires cultures performed on fresh tissues. However, molecular techniques such as pan-fungal polymerase chain reaction on paraffin blocks is becoming an increasingly useful tool to distinguish between cutaneous fungal pathogens. This review focuses on describing the clinical and histologic features of the most common fungal and oomycete infections affecting the skin of animals, divided according to distribution patterns of lesions and fungal or oomycete morphology.

Paraconiothyrium cyclothyrioides, a novel cutaneous fungal pathogen in a dog and a cat.

A dog and a cat presented with pyogranulomatous mycotic pododermatitis. Panfungal PCR and next-generation sequencing identified Paraconiothyrium cyclothyrioides with 100% identity. Paraconiothyrium cyclothyrioides can rarely cause cutaneous infection and systemic disease in immunocompromised humans. This is the first report of infections in domestic animal species.

Un chien et un chat sont présentés avec une pododermatite pyogranulomateuse d'origine fongique. La PCR panfongique et le séquençage de nouvelle génération ont identifié Paraconiothyrium cyclothyrioides avec un pourcentage d'identité de 100 %. Rarement, Paraconiothyrium cyclothyrioides peut provoquer une infection cutanée et une maladie systémique chez des humains immunodéprimés. Il s'agit du premier signalement d'infection dans des espèces animales domestiques.

Un perro y un gato presentaron pododermatitis micótica piogranulomatosa. La PCR panfúngica y la secuenciación de última generación identificaron Paraconiothyrium cyclothyrioides con un 100 % de identidad. Paraconiothyrium cyclothyrioides rara vez puede causar infección cutánea y enfermedad sistémica en humanos inmunocomprometidos. Este es el primer reporte de infecciones en especies de animales domésticos.

Um cão e um gato foram apresentados com pododermatite micótica piogranulomatosa. PCR panfúngico e sequenciamento de última geração identificaram Paraconiothyrium cyclothyrioides com 100% de identidade. Paraconiothyrium cyclothyrioides pode raramente causar infecções cutâneas e doença sistêmica em humanos imunocomprometidos. Este á o primeiro relato de infecções em animais domésticos.

Immunophenotype of the inflammatory response in the central and enteric nervous systems of cockatiels (Nymphicus hollandicus) experimentally infected with parrot bornavirus 2.

Proventricular dilatation disease is a lethal disease of psittacine birds. In this study, we characterized the local cellular immune response in the brain, proventriculus, and small intestine of 27 cockatiels (Nymphicus hollandicus) experimentally infected with parrot bornavirus 2 (PaBV-2). Perivascular cuffs in the brain were composed of CD3+ T-lymphocytes and Iba1+ macrophages/microglia in most cockatiels (n = 26). In the ganglia of the proventriculus, CD3+ T-lymphocytes (n = 17) and Iba1+ macrophages (n = 13) prevailed. The ganglia of the small intestine had a more homogeneous distribution of these leukocytes, including PAX5+ B-lymphocytes (n = 9), CD3+ T-lymphocytes (n = 8), and Iba1+ macrophages (n = 8). Our results indicate that perivascular cuffs in the brain and the inflammatory infiltrate in the proventriculus of PaBV-2-infected cockatiels is predominately composed of T-lymphocytes, while the inflammatory infiltrates in the ganglia of the small intestine are characterized by a mixed infiltrate composed of T-lymphocytes, B-lymphocytes, and macrophages.

In utero ultrafine particulate matter exposure causes offspring pulmonary immunosuppression.

Early life exposure to fine particulate matter (PM) in air is associated with infant respiratory disease and childhood asthma, but limited epidemiological data exist concerning the impacts of ultrafine particles (UFPs) on the etiology of childhood respiratory disease. Specifically, the role of UFPs in amplifying Th2- and/or Th17-driven inflammation (asthma promotion) or suppressing effector T cells (increased susceptibility to respiratory infection) remains unclear. Using a mouse model of in utero UFP exposure, we determined early immunological responses to house dust mite (HDM) allergen in offspring challenged from 0 to 4 wk of age. Two mice strains were exposed throughout gestation: C57BL/6 (sensitive to oxidative stress) and BALB/C (sensitive to allergen exposure). Offspring exposed to UFPs in utero exhibited reduced inflammatory response to HDM. Compared with filtered air (FA)-exposed/HDM-challenged mice, UFP-exposed offspring had lower white blood cell counts in bronchoalveolar lavage fluid and less pronounced peribronchiolar inflammation in both strains, albeit more apparent in C57BL/6 mice. In the C57BL/6 strain, offspring exposed in utero to FA and challenged with HDM exhibited a robust response in inflammatory cytokines IL-13 and Il-17. In contrast, this response was lost in offspring exposed in utero to UFPs. Circulating IL-10 was significantly up-regulated in C57BL/6 offspring exposed to UFPs, suggesting increased regulatory T cell expression and suppressed Th2/Th17 response. Our results reveal that in utero UFP exposure at a level close to the WHO recommended PM guideline suppresses an early immune response to HDM allergen, likely predisposing neonates to respiratory infection and altering long-term pulmonary health.

Characterization of staphylococcal communities on healthy and allergic feline skin.

BACKGROUND: Various Staphylococcus species have been demonstrated to play important roles on the skin, including causing disease and protecting the host from pathogens. Although culture-based studies have isolated various Staphylococcus spp. from feline skin, very little is known regarding the species-level communities on the host. HYPOTHESIS/OBJECTIVES: To describe the species-level staphylococcal communities inhabiting the skin of healthy cats and cats with allergic dermatitis. ANIMALS: Skin swabs from the ear canal and groin of 11 healthy and 10 allergic (nonlesional) cats were obtained. METHODS AND MATERIALS: DNA was extracted from the skin swabs and used for next-generation sequencing targeting the V1-3 region of the 16S rRNA gene. Following a standard microbiota analysis of the sequencing data, species-level assignment for the staphylococcal sequences were obtained using a staphylococci-specific database. RESULTS: Staphylococcus spp. had similar relative abundance in healthy and allergic samples. The most abundant staphylococcal species were S. epidermidis in healthy samples, and S. felis and S. capitis in allergic samples. The composition of staphylococcal communities, as well as relative abundance of Staphylococcus spp., was variable between body sites and individual cats sampled. CONCLUSIONS AND CLINICAL RELEVANCE: These results demonstrate that diverse staphylococcal communities inhabit the skin of healthy and allergic cats, and provide a starting point for further research into the importance of Staphylococcus spp. in feline allergic skin disease.

Characterization of the cutaneous mycobiota in Persian cats with severe dermatophytosis.

BACKGROUND: Persian cats are predisposed to chronic and severe dermatophytosis. Alterations to the cutaneous microbiota are one potential contributor to this predisposition. OBJECTIVES: To characterise the cutaneous and environmental fungal microbiota of Persian cats with chronic, severe dermatophytosis, and to compare the fungal microbiota of cats with and without dermatophytosis. ANIMALS: Thirty-six client-owned cats, including 26 Persian cats and 10 domestic long hair (DLH) cats. METHODS AND MATERIALS: Skin and home environment swabs were collected from Persian cats with severe, chronic dermatophytosis as well as groups of healthy control cats (Persian and DLH). Sequencing of the internal transcribed spacer 1 (ITS1) region was performed in addition to ITS1 quantitative PCR and fungal culture. RESULTS: Next-generation sequencing (NGS) targeting the fungal ITS region detected Microsporum sp. DNA from all Persian cats diagnosed with dermatophytosis and from environmental samples of their homes. A significant difference in community structure was identified between cases and controls, largely resulting from the Microsporum spp. DNA in samples from affected cats. Persian cats with dermatophytosis do not exhibit decreased fungal diversity. NGS failed to identify dermatophyte DNA on two culture-positive asymptomatic Persian controls and identified Trichophyton rubrum DNA from a culture-negative asymptomatic Persian control. CONCLUSIONS: Aside from M. canis, our results indicate that an underlying fungal dysbiosis is not likely to play a role in development of dermatophytosis in Persian cats. Other explanations for predisposition to this disease, such as a primary immunodeficiency, ineffective grooming or unique features of Persian cat hair should be investigated.

Pyogranulomatous panniculitis in a domestic cat associated with Pseudomonas luteola infection.

Pseudomonas luteola, a pathogen causing disease in humans, has in animals been reported only in rainbow trout and ferrets. This case report describes pyogranulomatous panniculitis in a cat associated with P. luteola infection. Organisms were seen histologically and identified with PCR and sequencing. Lesions resolved after treatment with marbofloxacin.

Pseudomonas luteola, un pathogène de l'homme, a été décrit chez l'animal seulement chez le furet et la truite arc en ciel. Ce cas clinique décrit une panniculite pyogranulomateuse chez un chat associée à une infection à P. luteola. Les organismes ont été vus à l'examen histopathologique et identifiés par PCR et séquençage. Les lésions se sont résolues après un traitement à la marbofloxacine.

Pseudomonas luteola, un patógeno que causa una enfermedad en los seres humanos, se ha reportado en animales solo en truchas arco iris y hurones. Este caso clínico describe una paniculitis piogranulomatosa en un gato asociada con una infección por P. luteola. Los organismos se observaron histológicamente y se identificaron mediante PCR y secuenciación. Las lesiones se resolvieron después del tratamiento con marbofloxacina.

Pseudomonas luteola é um patógeno causador de doença em humanos e, em animais, há relatos de sua ocorrência apenas em furões e trutas arco-íris. Este relato descreve um caso de paniculite piogranulomatosa em um gato associada à infecção por P. luteola. Os microrganismos foram observados histologicamente e identificados por PCR e sequenciamento. As lesões foram resolvidas após tratamento com marbofloxacino.

Cytokine expression in feline allergic dermatitis and feline asthma.

BACKGROUND: The pathogenesis of feline allergic dermatitis (FAD) is unclear, with several differences from allergic dermatitis in dogs and humans. HYPOTHESIS/OBJECTIVES: To survey cytokine expression levels in healthy cats and cats affected with allergic dermatitis or asthma. ANIMALS: Formalin-fixed, paraffin-embedded skin biopsies from 22 cats with allergic dermatitis and 21 cats without allergic dermatitis were used for cutaneous assays. Serum was obtained from 17 healthy cats, 18 cats with allergic dermatitis, and 18 cats with a presumptive diagnosis of asthma. METHODS AND MATERIALS: Cutaneous mRNA expression was evaluated with quantitative PCR [interleukin (IL)-31 and IL-31 Receptor A] and RNA in situ hybridisation (ISH) [IL-5, IL-31, IL-31RA, IL-33 and Oncostatin M receptor (OSMR)-ß]. IL-31 protein concentrations were evaluated in serum with an enzyme-linked immunosorbent assay. Serum levels of 19 additional cytokines were evaluated using a Luminex panel. RESULTS: IL-31, IL-31RA, IL-5 and IL-33 mRNA expression were either expressed in low quantities or undetectable in most samples. By contrast, OSMR-ß expression was significantly higher in the skin of allergic versus healthy cats (P < 0.0001). Although serum IL-31 was detected in a larger number of cats with allergic dermatitis than healthy cats, and concentrations appeared to be higher in cats with allergies, this difference was not statistically significant. Cats affected by asthma also exhibited insignificantly higher concentrations of IL-31 in the serum. CONCLUSIONS AND CLINICAL RELEVANCE: Our results suggest that feline allergic diseases may exhibit different pathomechanisms from allergic diseases affecting other species. These findings are useful in guiding further therapeutic development toward targets that may have a role in the pathogenesis of feline allergic skin disease.

Distribution of Viral Antigen and Inflammatory Lesions in the Central Nervous System of Cockatiels ( Nymphicus hollandicus) Experimentally Infected with Parrot Bornavirus 2.

Neurotropism is a striking characteristic of bornaviruses, including parrot bornavirus 2 (PaBV-2). Our study evaluated the distribution of inflammatory foci and viral nucleoprotein (N) antigen in the brain and spinal cord of 27 cockatiels ( Nymphicus hollandicus) following experimental infection with PaBV-2 by injection into the pectoral muscle. Tissue samples were taken at 12 timepoints between 5 and 114 days post-inoculation (dpi). Each experimental group had approximately 3 cockatiels per group and usually 1 negative control. Immunolabeling was first observed within the ventral horns of the thoracic spinal cord at 20 dpi and in the brain (thalamic nuclei and hindbrain) at 25 dpi. Both inflammation and viral antigen were restricted to the central core of the brain until 40 dpi. The virus then spread quickly at 60 dpi to both gray and white matter of all analyzed sections of the central nervous system (CNS). Encephalitis was most severe in the thalamus and hindbrain, while myelitis was most prominent in the gray matter and equally distributed in the cervical, thoracic, and lumbosacral spinal cord. Our results demonstrate a caudal to rostral spread of virus in the CNS following experimental inoculation of PABV-2 into the pectoral muscle, with the presence of viral antigen and inflammatory lesions first in the spinal cord and progressing to the brain.

Pulmonary and systemic fungal infections in an Atlantic spotted dolphin and a Bryde's whale, Brazil.

We report the gross and microscopic findings and molecular identification of 2 cases of hyphate fungal infection in cetaceans from Brazil. The first case involved an adult male Atlantic spotted dolphin Stenella frontalis with localized pulmonary disease characterized by pyogranulomatous and necrotizing bronchopneumonia with intralesional hyphae. The second case involved an adult male Bryde's whale Balaenoptera edeni with orchitis, periorchitis, mesenteric lymphadenitis and pyogranulomatous bronchopneumonia with intralesional hyphae. PCR analysis from the dolphin's lung yielded Aspergillus fumigatus, and the fungus from the whale's mesenteric lymph node showed the greatest identity to Nanniziopsis obscura and Stagonosporopsis cucurbitacearum These cases represent the first reports of pulmonary aspergillosis by A. fumigatus in an Atlantic spotted dolphin and systemic mycosis by a possibly novel Onygenales in marine mammals.

Novel association of Psychrobacter and Pseudomonas with malodour in bloodhound dogs, and the effects of a topical product composed of essential oils and plant-derived essential fatty acids in a randomized, blinded, placebo-controlled study.

BACKGROUND: The pathogenesis and treatment of cutaneous malodour in dogs have not been investigated previously. Staphylococcus and Corynebacterium spp. are associated with human axillary malodour. HYPOTHESIS: Staphylococcus and Corynebacterium spp. are associated with cutaneous malodour in dogs, and treatment with a topical essential oil-based product will improve malodour and reduce the abundance of odour-causing bacteria. ANIMALS: Twenty seven bloodhound dogs from a south Texas boarding facility were enrolled in this study. METHODS AND MATERIALS: Skin swabs were taken from the axilla and dorsum of 27 dogs at initiation of the study. Mean malodour scores were used to assign dogs to control or malodour groups. The malodourous dogs were randomly assigned to a treatment or placebo group, received four weekly topical applications of the spot-on or placebo, and samples were recollected. Next-generation sequencing (NGS) and real-time quantitative PCR (qPCR) were performed on all swabs. RESULTS: Psychrobacter and Pseudomonas spp. were significantly more abundant (P < 0.001, P = 0.006; respectively), and overall bacterial diversity was reduced (P = 0.0384) on the skin of malodourous dogs. Staphylococcus and Corynebacterium spp. were not associated with malodour. The topical essential oil-based product significantly (P = 0.0078) improved malodour in the treatment group and shifted their bacterial community structure. CONCLUSIONS AND CLINICAL IMPORTANCE: A novel association of bacterial genera with malodour in bloodhound dogs, identified by NGS, highlights future targets for odour control. The topical treatment significantly reduced malodour. The interaction between the topical treatment and cutaneous microbiota should be further investigated and may be useful in other dermatological conditions involving microbiota.

Chaetomiaceae Fungi, Novel Pathogens of Equine Neurotropic Phaeohyphomycosis.

Many previously unrecognized fungi are emerging as potential pathogens. One such group is dematiaceous fungi of the Chaetomiaceae family (phylum Ascomycota, class Sordariomycetes). These fungi are rare causes of opportunistic, neurotropic phaeohyphomycosis in humans but are not known to cause similar infections in animals. The aims of this study were to investigate equine hyphal mycotic encephalitis, characterize key histopathologic features, and classify causative organisms with molecular diagnostic techniques. Seven cases were evaluated by histopathology. Panfungal PCR targeting the ribosomal RNA large subunit coding region and the noncoding internal transcribed spacer-2 region was performed on DNA extracted from formalin-fixed, paraffin-embedded sections of affected brain, and the resulting sequences were queried against published fungal genomes. Affected animals ranged from 8 to 22 years of age and presented with neurologic signs. Macroscopic lesions within affected brains included multifocal hemorrhage, focal swelling of the thalamus with red and yellow discoloration, and focal cerebral malacia. Major histologic findings included multifocal discrete foci of necrosis, neutrophilic to granulomatous inflammation, vasculitis, and intralesional fungal hyphae variably affecting the cerebrum, thalamus, and brainstem. DNA sequences in 4 cases showed > 98% homology with species within the Chaetomiaceae family, including Acrophialophora fusispora, Acrophialophora levis, and Chaetomium strumarium. Histomorphologically, Chaetomiaceae fungi were 7 to 10 µm wide, septate, parallel walled, and nonpigmented, with dichotomous branching in affected horses. This case series is the first report of equine mycotic encephalitis caused by members of the Chaetomiaceae family, previously reported as rare emerging pathogens in humans.

The cutaneous ecosystem: the roles of the skin microbiome in health and its association with inflammatory skin conditions in humans and animals.

BACKGROUND: Inhabiting a sterile world is no longer an acceptable or desirable concept. Recent studies developed in the microbiome field have unveiled complex microbial populations inhabiting the skin, digestive, respiratory and reproductive tracts. Microbiome studies have opened new venues to explore the human and animal second genome, its functions and its importance in maintaining health. SKIN MICROBIOME IN HEALTH: The composition of the skin microbiome varies across different body sites and across individuals, being influenced by different host habits, including for instance age, sex, diet, hygiene and lifestyle. Exposure to a diverse skin microbiome is now considered to be a key component in immune regulation, and imbalances in these microbial populations are being associated with human and animal skin inflammatory disorders. SKIN MICROBIOME IN INFLAMMATORY SKIN CONDITIONS: We have learned that in several skin conditions, there is a significant alteration in the diversity and composition of the microbiota colonizing the skin. For instance, in human and animal patients with atopic dermatitis, dysbiosis of the skin microbiota results in lower diversity of microbial populations. Whether these altered microbial populations are the cause or the effect of inflammatory skin conditions seen in humans and animals are still under investigation, but there is no doubt that the microbiome has an important role in maintaining skin health. SUMMARY: This review focuses on the most current studies describing the skin microbiome in humans and animals, its role in modulating the immune system, and its association with human and animal skin diseases.

Atypical cutaneous cryptococcosis in four cats in the USA.

BACKGROUND: Cryptococcosis is an uncommon fungal infection in humans and mammals. Occasionally, cryptococcosis manifests as cutaneous lesions, either as an extension of nasal disease or as stand alone lesions unassociated with the nose. Histologically, these lesions are typically characterized by abundant organisms with mild granulomatous dermatitis. Herein, four feline cases of atypical cutaneous cryptococcal infections are described. METHODS: Skin punch biopsies from four client owned cats were submitted for histological evaluation between 2006 and 2015. Histological examination, including histochemical stains, was performed in all cases. Immunohistochemical stains and PCR were performed in three of four cases. Fungal culture was performed in two cases and transmission electron microscopy was performed in one case. RESULTS: Grossly, the cutaneous lesions were papular to nodular with occasional ulceration and were located predominantly on the trunk. Histological examination revealed severe granulomatous to pyogranulomatous and eosinophilic dermatitis with rare, capsule-deficient yeasts. Immunohistochemistry, PCR and fungal culture confirmed Cryptococcus spp. to be the aetiological agent in these cases. CONCLUSIONS AND CLINICAL IMPORTANCE: In cutaneous lesions, capsule-deficient strains of Cryptococcus spp. may induce a severe inflammatory response with rare intralesional organisms that may not be readily identified on routine haematoxylin and eosin stained slides. Special stains with careful examination and ancillary tests (PCR, immunohistochemistry, fungal culture or antigen testing) should be performed when pyogranulomatous and eosinophilic dermatitis is encountered without an identifiable cause.

Characterization of the cutaneous mycobiota in healthy and allergic cats using next generation sequencing.

BACKGROUND: Next generation sequencing (NGS) studies have demonstrated a diverse skin-associated microbiota and microbial dysbiosis associated with atopic dermatitis in people and in dogs. The skin of cats has yet to be investigated using NGS techniques. HYPOTHESIS/OBJECTIVES: We hypothesized that the fungal microbiota of healthy feline skin would be similar to that of dogs, with a predominance of environmental fungi, and that fungal dysbiosis would be present on the skin of allergic cats. ANIMALS: Eleven healthy cats and nine cats diagnosed with one or more cutaneous hypersensitivity disorders, including flea bite, food-induced and nonflea nonfood-induced hypersensitivity. METHODS: Healthy cats were sampled at twelve body sites and allergic cats at six sites. DNA was isolated and Illumina sequencing was performed targeting the internal transcribed spacer region of fungi. Sequences were processed using the bioinformatics software QIIME. RESULTS: The most abundant fungal sequences from the skin of all cats were classified as Cladosporium and Alternaria. The mucosal sites, including nostril, conjunctiva and reproductive tracts, had the fewest number of fungi, whereas the pre-aural space had the most. Allergic feline skin had significantly greater amounts of Agaricomycetes and Sordariomycetes, and significantly less Epicoccum compared to healthy feline skin. CONCLUSIONS: The skin of healthy cats appears to have a more diverse fungal microbiota compared to previous studies, and a fungal dysbiosis is noted in the skin of allergic cats. Future studies assessing the temporal stability of the skin microbiota in cats will be useful in determining whether the microbiota sequenced using NGS are colonizers or transient microbes.

The skin microbiome in allergen-induced canine atopic dermatitis.

BACKGROUND: Studies focusing on next-generation sequencing of the bacterial 16S rRNA gene have allowed detailed surveys of skin bacterial populations (microbiota) of the skin. HYPOTHESIS/OBJECTIVES: This study evaluated temporal changes in the skin microbiota in a canine model of atopic dermatitis. ANIMALS: Eight atopic dogs previously sensitized with house dust mites (HDM). METHODS: The dogs were topically challenged on the right groin with HDM allergens. Swabs were collected from the challenged and the contralateral nonchallenged sites prior to provocation (pre-challenge; baseline sample) and on days 1, 7, 14, 21 and 28 after allergen challenge. The 16S rRNA gene was amplified, sequenced and analysed. Staphylococcus spp. and Staphylococcus pseudintermedius were quantified with quantitative PCR (RT-qPCR). RESULTS: Skin lesions developed in all dogs on the challenged sites. Differences in bacterial groups were observed on the challenged site over time. Relatively lower abundances of Fusobacteriaceae on Day 7, and, based on LEfSe, increased abundances of Corynebacteriaceae on Day 1, and Staphylococcaceae on days 7, 14 and 21, were observed on the challenged site, compared to the contralateral site. Results of RT-qPCR correlated with those of next-generation sequencing, with significantly increased numbers of Staphylococcus spp. and S. pseudintermedius on Day 21, and days 7 and 21 on the challenged site compared to the contralateral site, respectively. CONCLUSIONS AND CLINICAL IMPORTANCE: This study demonstrates that an allergen challenge in sensitized dogs leads to bacterial dysbiosis with increased abundance of S. pseudintermedius at the site of lesion induction.