Culture-independent and dependent evaluation of the equine paranasal sinus microbiota in health and disease

BACKGROUND

Horses with bacterial sinusitis frequently undergo empirical treatment with antimicrobials, however, in some cases bacterial culture of the affected sinus is used to direct therapy. Data regarding which organisms are part of the commensal microbiota of the equine sinus are lacking making it difficult to interpret culture results and guide empiric antimicrobial selection.

OBJECTIVES

Our objectives were to describe the bacterial and fungal microbiota of the paranasal sinuses in clinically normal horses using culture-dependent and independent approaches and to compare the bacterial culture and susceptibility patterns of normal horses with those from horses affected with primary and secondary sinusitis.

STUDY DESIGN

Experimental study and descriptive retrospective review of case records.

METHODS

Sinus washes were collected from 23 healthy horses. Washes were submitted for routine culture and susceptibility testing and DNA was isolated for next generation sequencing of bacterial and fungal marker genes. For clinical cases of sinusitis, medical records from 2010 to 2017 were reviewed and horses diagnosed with primary and/or secondary sinusitis were included.

RESULTS

The paranasal sinus cavity hosts multiple bacterial and fungal organisms. The bacterial microbiota of healthy horses consists largely of uncultivable, aerobic bacteria. While few anaerobes were isolated from normal horses, the majority of clinical cases resulted in growth of anaerobic organisms with no difference in the proportion of aerobic and anaerobic bacteria isolated from clinical cases.

MAIN LIMITATIONS

Small sample size in both populations of horses and heterogeneity of the population prevent a more in-depth analysis.

CONCLUSIONS

The microbiota of the paranasal sinuses of horses consists primarily of aerobic bacteria and fungal organisms, the majority of which are uncultivable via common clinical methods. Anaerobic bacteria are found in the majority of horses with clinical sinusitis. These findings suggest anaerobic bacteria are associated with sinusitis and their presence should be considered when treating horses with sinusitis.

Evaluation of the potential use of adipose-derived mesenchymal stromal cells in the treatment of canine atopic dermatitis: a pilot study

Stem cells and their potential therapeutic uses in human and veterinary medicine have generated considerable interest. These cells have a number of potentially unique immunologic properties; most notable are their reported regenerative and antiinflammatory capabilities. The aim of this prospective pilot study was to evaluate the efficacy of intravenously administered autogenous adipose-derived mesenchymal stem cells (AD-MSCs) in the treatment of canine atopic dermatitis. AD-MSCs administered intravenously at a dose of 1.3 million cells/kg did not significantly reduce the clinical signs of canine atopic dermatitis or the owner-assessed pruritus level.

Comparative adrenocortical suppression in dogs with otitis externa following topical otic administration of four different glucocorticoid-containing medications

The safety of using otic formulations is often of concern for practitioners and pet owners alike, with "safe" in this context meaning no adrenocortical suppression. This study evaluated the effect of four glucocorticoid-containing otic formulations on plasma cortisol concentrations, measured by corticotropin stimulation testing (plasma cortisol concentrations before and after corticotropin injection), in dogs presented with otitis externa. Dexamethasone tended to have larger adrenocortical suppression compared with the other three formulations (betamethasone, triamcinolone, and mometasone), but the difference was not statistically significant. The largest difference among the four drugs was observed between dexamethasone and betamethasone (P=.09).

Canine discoid lupus erythematosus

Two dogs were found to have clinical, histopathological and immunofluorescent findings compatible with a diagnosis of canine discoid lupus erythematosus. The primary lesions included erythema and depigmentation of the nasal planum. Both dogs responded favorably to systemic corticosteroid therapy.

Identification of snails within the Bulinus africanus group from East Africa by multiplex SNaPshot trade mark analysis of single nucleotide polymorphisms within the cytochrome oxidase subunit I

Identification of populations of Bulinus nasutus and B. globosus from East Africa is unreliable using characters of the shell. In this paper, a molecular method of identification is presented for each species based on DNA sequence variation within the mitochondrial cytochrome oxidase subunit I (COI) as detected by a novel multiplexed SNaPshotTM assay. In total, snails from 7 localities from coastal Kenya were typed using this assay and variation within shell morphology was compared to reference material from Zanzibar. Four locations were found to contain B. nasutus and 2 locations were found to contain B. globosus. A mixed population containing both B. nasutus and B. globosus was found at Kinango. Morphometric variation between samples was considerable and UPGMA cluster analysis failed to differentiate species. The multiplex SNaPshotTM assay is an important development for more precise methods of identification of B. africanus group snails. The assay could be further broadened for identification of other snail intermediate host species.

The ACVD task force on canine atopic dermatitis (XXI): antihistamine pharmacotherapy

Antihistamines frequently are recommended by veterinary dermatologists for symptomatic treatment of pruritus associated with canine atopic dermatitis (AD), perhaps because of their moderate success in some human patients with AD. A critical review of the literature describing antihistamine use in canine AD reveals that the majority of published, peer-reviewed studies are open, uncontrolled or partially-controlled trials. Such studies vary widely in reported efficacy, from perhaps 0 to 75% of patients, even using the same drug. The few blinded placebo-controlled trials available have failed to confirm efficacy of these drugs to relieve the pruritus of canine AD. Some studies indicate that synergistic effects could occur with concurrent use of essential fatty acid supplements. Consequently, at the time of this writing, there is insufficient evidence to conclude for or against the efficacy of antihistamines for treatment of canine AD. Additional blinded, randomized and controlled trials with larger numbers of patients are necessary to establish which of the antihistamine drugs currently available, if any, are truly efficacious for canine AD. Nevertheless, present clinician consensus suggests that several different antihistamine drugs should be evaluated in sequence, for 7-14 days each, in canine patients with AD.

The ACVD task force on canine atopic dermatitis (I): incidence and prevalence

There is an increasing incidence of atopic diseases (asthma, allergic rhinitis and atopic dermatitis) in humans, especially in developed countries. Although there is a genetic predisposition to the development of these diseases, the rapid rise in incidence is suspected to be caused by environmental rather than genetic factors. Neither the incidence nor the prevalence of atopic dermatitis in the general canine population has been studied. As many of the environmental factors associated with the increasing incidence of atopic dermatitis in humans are consistently found in the environment of dogs, it would seem likely that a similar increase in the incidence of this disease would be occurring also in dogs. Epidemiological studies of canine atopic dermatitis are needed to characterize the incidence and prevalence of atopic dermatitis, and to further study the factors that contribute to the development of this disease.

The ACVD task force on canine atopic dermatitis (XIV): clinical manifestations of canine atopic dermatitis

Canine atopic diseases, including those with skin lesions, have been described for many years. Unfortunately, early descriptions often failed to establish definitive guidelines for considering a patient atopic, and criteria for diagnosing atopic dermatitis (AD) have varied from author to author. Larger case-series published from the 1960s to the 1980s suggested that the most common clinical manifestation of AD was pruritus, particularly of the face, ears, paws, extremities, and/or ventrum. It is not always clear that testing to eliminate other differential diagnoses was always carefully performed on patients in early reports; therefore, some descriptions could include patients affected with diseases other than or in addition to AD. Points of consensus regarding clinical manifestations of AD in case-series include the presence of pruritus beginning at a young age, possibly seasonally; and a prominent lesional involvement of the face, extremities, axillae or ventrum. Conflicting information on breed and sex predispositions is present, perhaps representing regional or temporal variability. Clinical reports vary, in regard to the description of lesions seen in dogs with AD. This reflects a possible confusion with lesions of secondary complications, and highlights the fact that the existence and nature of primary lesions of canine AD are not truly known.

The ACVD task force on canine atopic dermatitis (XXIV): allergen-specific immunotherapy

Allergen-specific immunotherapy (ASIT) has been used for years to treat dogs with atopic dermatitis (AD) and humans with atopic diseases. The efficacy of ASIT has been well documented for humans with respiratory atopic diseases and stinging insect allergy, but its effectiveness seems more controversial for patients with AD. In spite of insufficient evidence derived from randomized controlled trials, multiple open studies and a large body of clinical observations suggest that ASIT is effective in controlling the clinical signs of dogs with AD. As a result of the scarcity of evidence from controlled trials, the true efficacy of ASIT, and the optimal protocols for allergen dose and frequency of injection are currently unknown. Allergen-specific immunotherapy nevertheless may be included in the treatment of canine AD because of its potential advantages and limited disadvantages compared to other forms of therapy. There is no evidence, however, for the preference of any specific treatment protocol. The predictive value of historical, clinical and immunologic features related to the efficacy of ASIT in dogs with AD are discussed in this paper. Adverse reactions, and the requirements for monitoring of patients receiving ASIT, then are reviewed and detailed. Finally, this review highlights aspects of ASIT where further research and controlled studies are needed.

The ACVD task force on canine atopic dermatitis (X): is there a relationship between canine atopic dermatitis and cutaneous adverse food reactions?

In humans, allergies to foods are known to induce skin lesions in some patients with atopic dermatitis. This is particularly evident in infants with severe atopic dermatitis. Food allergy in humans is an IgE-mediated hypersensitivity in most cases, and thus has the same (or very similar) pathogenic mechanism of disease induction as environmental allergen-induced atopic dermatitis. Cutaneous adverse food reactions and atopic dermatitis in dogs are often indistinguishable from each other on historical and clinical grounds alone. Limited current evidence suggests that dogs with cutaneous adverse food reactions may be predisposed to developing atopic dermatitis. However, confirmation of any association between these two diseases in dogs awaits further elucidation of the pathogenic mechanism of cutaneous adverse food reactions, and epidemiological studies of the relative prevalence of these diseases in relation to each other and the general population.

Onychectomy as a therapy for symmetric claw and claw fold disease in the dog

Chronic onychodystrophies are a group of diseases that are frustrating and potentially expensive to manage. Despite appropriate diagnostics, an underlying etiology may not be identified. Long-term therapy may result in resolution or remission; however, relapses are common. In many cases, the disease persists in the face of appropriate therapy. Seven dogs with chronic onychodystrophies were treated with onychectomies. Treatment resolved the clinical signs for a follow-up period of four months to six years.

Factors associated with and prevalence of high Malassezia pachydermatis numbers on dog skin

The prevalence of cutaneous Malassezia spp was evaluated in a semiquantitative fashion at 3 sites on 98 dogs examined because of various dermatoses. Thirty (10.2%) of the sites and 19 (19.4%) of the dogs had Malassezia spp amounts higher than that found on grossly normal skin. The prevalence of higher than normal amounts did not correlate significantly with sample site, sex, or age. The factors associated with an increased prevalence of increased Malassezia spp counts were seborrheic dermatitis, recent antibiotic treatment, and breed.

Pemphigus foliaceus in dogs: a review of 37 cases

Thirty-seven dogs with pemphigus foliaceus were seen over a span of 9 years in a veterinary medical teaching hospital. Four breeds of dogs (Bearded Collie, Akita, Newfoundland, Schipperke) were at significant elevated risk when compared with both the dermatology canine case population and the hospital canine population. The mean age of onset was 4.2 years. The dorsal part of the muzzle was the most common site of initial involvement in over 50% of the dogs, and lesions of the head were seen first in 81% of the dogs. Disease progression was gradual (greater than 3 months) in 73% of the dogs. Somewhat bilaterally symmetric scaling, crusting, and alopecia were seen in all of the dogs. Vesicles, pustules, and bullae were not seen commonly, but target lesions with peripheral collarettes were seen frequently. Most dogs had characteristic footpad lesions, with erythematous swelling at the pad margins, cracking, and villous hypertrophy. Generalized exfoliative dermatitis was seen in dogs with widespread disease. Pruritus was noted in less than one half of the dogs. Typical histopathologic findings included subcorneal and intragranular cell layer epidermal pustules, or intrafollicular pustules with prominent acantholysis. Direct immunofluorescence in an intercellular pattern was noted in 76% of the dogs tested and indirect immunofluorescence was noted in 75% of a much smaller sample. Thirty-nine percent of the dogs responded to corticosteroid therapy alone, and 50% and 55% responded, respectively, to prednisone and cytotoxic drugs, and to prednisone with aurothioglucose. Aurothioglucose was successful alone in 27% of the dogs. One-year survival was achieved in 53% of the dogs.

Pemphigus foliaceus of the footpads in three dogs

Severe hyperkeratinization and villous hypertrophy of the footpads were seen in 3 middle-aged dogs. Peeling, fissuring, swelling, and ulcerations were noted on the margins of severely affected pads. Pain was evident in palpation and ambulation. Lesions were compatible with the traditional diagnosis of "hard pad disease". Histopathologic findings were diagnostic for canine pemphigus foliaceus in all 3 dogs, and direct immunofluorescence in an intercellular pattern was seen in both dogs that were tested. All 3 dogs responded to immunosuppressive dosages of corticosteroids.