The efficacy of an antiseptic and microbial anti-adhesive ear cleanser in dogs with otitis externa

A new antimicrobial ear cleanser was evaluated for the treatment of bacterial and yeast ear infection in dogs. Forty-five dogs with erythemato-ceruminous or purulent otitis externa were randomly allocated to two treatment groups: reference ear cleanser (Epiotic, Virbac) or test ear cleanser (Epiotic Advanced, Virbac). Ear cleansing was performed twice daily for 2 weeks, and no other treatment was allowed. By week 2, clinical (exudate quantity, erythema, stenosis, excoriation, and odor) and discomfort (pain, ear scratching, and head shaking) scores were significantly decreased (P < .0001 for all) and no microbial overgrowth could be detected in 25 (64.1%) and 32 (68.1%) ears treated with Epiotic and Epiotic Advanced, respectively. The new pH-balanced, propylene glycol-free test ear cleanser, which incorporates microbial adhesin-blocking carbohydrates, proved as effective as the reference acidic formula.     

Evaluation of a cuprimyxin-hydrocortisone acetate suspension in the treatment of otitis externa in dogs and cats.

The therapeutic efficacy of a 0.5% cuprimyxin plus 1% hydrocortisone acetate-water-base suspension was evaluated in 130 clinical cases of otitis externa in dogs and cats in various geographic areas of the United States. The otic microbial flora was studied before treatment in 125 (96%) of the dogs and cats, with multiple isolates recovered from mated from 70%, yeasts from 65%, and fungi from 5% of the animals. Evens though multiple drug reistance was frequently observed in the bacterial flora, all bacteria and yeast isolates were sensitive to cuprimyxin. Of the 130 treated animals, a statistically significant (P less than 0.01) favorable response was obtained in 84,6% and no response in 13;1%; in2.3%, the condition became worse. An adverse reaction (pain at the time of first application) was observed in 1 (0.8%) animal.     

Diagnosis and medical treatment of otitis externa in dogs and cats

A review of otitis externa in dogs and cats is presented. Aetiology, includes primary causes: ectoparasitoses, allergic diseases, endocrine disorders, pyodermas, trauma and irritation, contact dermatitis, auto-immune skin diseases, drug eruption, keratoseborrhoeic skin disease, tumours and pseudoneoplastic lesions, as well as secondary causes: bacteria and yeasts. Clinical aspects are variable but a practical classification distinguishes two forms: erythematoceruminous otitis externa and suppurative otitis externa. Diagnosis is made in five steps which are clinical examination, direct examination of cerumen (erythematoceruminous otitis externa) or bacterial culture and sensitivity testing (suppurative otitis externa), direct impression smears, cleaning and otoscopy, and diagnosis of underlying skin disease. Medical therapy includes cleaning of the external ear canal and local therapy (acaricides, antifungal agents, antibiotics, corticosteroids, other topical agents, the appropriate selection of an optic preparation being essential). Treatment of underlying skin disease is always necessary. Otitis externa is in fact a dermatological disease complex (like pododermatitis). Although local secondary infections (bacterial and fungal) must be managed in every case, there are grounds for including otitis externa in a larger frame.     

Pull-through technique for vertical canal ablation for the treatment of otitis externa in dogs and cats

An alternative technique to ablate the vertical segment of the external auditory meatus, applicable to dogs and cats, is described. The results of this surgery in 11 dogs and one cat are compared with those in seven dogs using the traditional ablation procedure.     

Evaluation of the patient with otitis externa

This article considers the history, physical examination, cytologic evaluation of smears and fungal and bacterial culture and sensitivity testing, clinical interpretation of information obtained from a biopsy of the external ear canal, and ancillary aids for the evaluation of the patient with otitis externa.     

Comparison of microbial isolates and susceptibility patterns from the external ear canal of dogs with otitis externa

Otic exudate was obtained from 33 dogs with otitis externa for cytopathology and culture. Two samples were taken from the same location in the external ear canal, for a total of 100 samples. Thirty-six (36%) samples isolated only a single organism, of which 21 (21%) were Malassezia spp. Two organisms were present in 23 (23%) of the samples. Cultures of the two samples agreed in 40 (80%) of the 50 pairs. Cytopathology agreed with culture results only 68% of the time. Cytopathology and culture may not be as definitive as previously assumed because of apparent variability of the microbial population within the external canal.     

Bacteriology and mycology of otitis externa in dogs]

The bacterial and fungal flora of 1118 ears of dogs with otitis externa and 100 ears of healthy control dogs were studied in order to isolate the causative agents. The yeast Malassezia pachydermatis (56%) was by far the most common organism in otitic dogs followed by the bacteria Staphylococcus intermedius (23%), Pseudomonas aeruginosa (12%), Proteus spp. (6%) and Streptococcus canis (5%). A statistical analysis of observed results showed that the incidence of these organisms is significant in otitic dogs. Many strains of S.intermedius, P.aeruginosa and Proteus spp. are resistant to antimicrobial agents commonly used to treat otitis externa. Therefore an antimicrobial susceptibility testing was performed using "Cobas Bact" for these bacterias. Furthermore, 80 strains of M.pachydermatis were submitted to identification-kits (API 20 CAUX, API STAPH, Cobas Micro). The observed results showed that an identification with these tests was not possible.     

FC-46 Methicillin-resistant Staphylococcus intermedius organisms from the vertical ear canal of dogs with end-stage otitis externa

Different mite species generally found on animals may temporarily also infest humans. Consequently, these arthropods may be responsible for pruritic skin reactions that are often misdiagnosed. Mite dermatitis caused by the tropical rat mite Ornithonyssus bacoti occurs in several small mammals and rodents under tropical and temperate climatic conditions. According to various observations in Germany, O. bacoti appears in wild rodents more frequently than previously thought. In most cases, symptoms of mites are recognized only when they attack humans, but the diagnosis of rat mite dermatitis requires identification of the parasite, which is more likely to be found in the environment than on the hosts' skin itself. Here, five different outbreaks from Bavaria are reported. A clinical example is the case of a 23-year-old medical student and several other residents inhabiting a rat- and mouse-infested house in Munich. The arthropods originally came from an Italian restaurant and surrounding facilities. Mites were found in large numbers in the students' flat. The patient was suffering from severe itching and papular urticaria. He consulted a dermatology clinic complaining of a pruritic dermatitis of 2-weeks duration. Dermatitis was misdiagnosed as allergy and treatment with an anti-inflammatory agent was unsuccessful. Eradication of rodents and treatment of the house with a pyrethroid were performed to prevent reinfestation. Ornithonyssus bacoti is a periodic haematophageous parasite and spends a relatively short time on the host. Causal therapy with antiparasitic agents on human patients is not necessary. If indicated, treatment should be symptomatic.
Funding: Self-funded.     

Total ear canal ablation combining bulla osteotomy and curettage in dogs with chronic otitis externa and media

Ear canal ablation combining bulla osteotomy and curettage was performed on 44 dogs (n = 72 ears). Indications for the procedure included one or more of the following: chronic nonresponsive otitis externa and/or media (n = 71), tumor in the horizontal portion of the ear canal (n = 1), failed lateral ear resection (n = 11), ossified auricular cartilages secondary to chronic otitis externa (n = 22), failed previous total ear canal ablation (n = 1), and otitis interna (n = 1). In 40 dogs, the surgery was successful in alleviating all clinical signs of otitis externa and media. During the immediate postoperative period, 2 dogs died of causes unrelated to otitis. Complications related to the surgery developed in 9 of the surviving 42 dogs. Ultimately, 95% (40 of the surviving 42) of the dogs were cured by use of this procedure. Surgery successfully resolved the original problems in 97% (66 of 68) of the surgically treated ears of these dogs.     

New combination for the therapy of canine otitis externa I Microbiology of otitis externa

In order to compound a new drug comblnatlon agalnst canlne otitis externa (OE), 515 dogs affected wlth OE were subjected to physical examlnatlon and mlcroblologlcal analysis of their ear exudates. OE was erythematous-cerumlnous In 83 per cent and suppurative In 17 per cent of the patlent material. Erythematous-cerumlnous lnflammatlons were characterlsed by severe prurltus and accumulatlon of brownlsh, greasy cerumen In the audltory canal. The yeast Malassezla jmchydermat/s was Isolated from the ears of 76 per cent of the dogs, often In comblnatlon wlth Staphylococcus lntermedlus bacterla. M pachydermatls showed the most sensltlvlty, In decreasing order of efflcacy, to ketoconazole, econazole, clotrlmazole, mlconazole and nystatln. S lntermedlus Isolates were most sensltlve to amoxyclllln-clavulanlc acld, enrofloxacln, cephalexln and gentamlcln. The mlcroorganlsm most frequently Isolatcbd from dogs wlth suppurative OE was Pseudomonas aewglnosa; In some cases Proteus, Streptococcus and Pasteurella were also Isolated. The P aeruglnosa Isolates showed the highest sensltlvlty to gentamlcln, polymyxln B and tobramycln.     

Ulcerative otitis externa responsive to immunosuppressive therapy in two dogs

Two middle-aged dogs were presented with bilateral severe ulcerative otitis externa without previous history of disease or evidence of other skin disease. Based on the exclusion of microbial infection and other primary causes, histopathological findings and response to immunomodulatory treatment, a diagnosis of presumed immune-mediated ulcerative otitis externa was made in both cases. However, the two cases differed with regard to their histopathological characteristics and the course of the disease. This report indicates that primary ulcerative disease needs to be considered in cases of ulcerative otitis externa which are unresponsive to appropriate antimicrobial therapy.     

Long-term evaluation of the pull-through technique for vertical canal ablation for the treatment of otitis externa in dogs and cats

Between January 1985 and May 1987 53 ears of 35 dogs and five cats with chronic otitis externa were operated on using the pull-through technique for vertical canal ablation. Their postoperative follow-up is analysed, evaluated and described in detail.     

The bacteriological and clinical assessment of a new preparation for the treatment of otitis externa in dogs and cats

The efficacy of a preparation (Oterna—Glaxo Laboratories Ltd) for use in the treatment of otitis externa in small animals has been assessed bacteriologically. The aetiology of the disease was studied in 133 ears of cats and dogs; normal ears were examined by comparison. Pityrosporum canis and staphylococci were the organisms most commonly isolated; their incidence was much higher in clinically affected ears than in normal ears. Gram-negative organisms were found only in diseased ears. Seventy-three clinical cases of otitis in dogs and cats were treated with a preparation containing neomycin, monosulfiram and betamethasone. Bacteriological and clinical evaluations were made before and after treatment and the organisms isolated were tested for sensitivity to the antimicrobial constituents of the preparation. There was a 92 % correlation between the bacteriological and clinical results. A ‘good’ or ‘very good’ bacteriological response was recorded for 71% of the ears treated. Résumé. On a évalué bactériologiquement l'efficacité d'une préparation (Oterna—Glaxo Laboratories Ltd) pour l'usage dans le traitement de l'otite externe de petits animaux. L'étiologie de la maladie a été étudiée dans 133 oreilles de chats et chiens; des oreilles normales ont été examinées pour comparaison. Le Pityrosporum canis et des staphylocoques ont été les microorganismes le plus souvent isolés; leur incidence était beaucoup plus élevée dans les oreilles affectées cliniquement que dans les oreilles normales. Des micro-organisms Gram-négatifs ont été seulement trouvés dans les oreilles malades. Soixante-treize cas cliniques d'otite chez les chats et les chiens ont été traités avec une préparation contenant de la néomycine, du monosulfiram et du bétaméthazone. Les évaluations bactériologique et clinique ont été faites avant et après le traitement et les micro-organismes isolés ont été vérifiés pour la sensibilité aux constituants antimicrobiens de la préparation. Il y avait une corrélation de 92% entre les résultats bactériologiques et cliniques. On a enregistré une réaction bactériologique ‘bonne’ ou ‘très bonne’ dans 71% des oreilles traitées. Zusammenfassung. Die Wirksamkeit eines Präparats (Oterna—Glaxo Laboratories Ltd) für die Behandlung von äußerer Otitis bei kleinen Tieren ist bakteriologisch bestimmt worden. Die Ursachenforschung dieser Krankheit wurde an 133 Ohren von Katzen und Hunden durch-geführt. Zum Vergleich wurden normale Ohren untersucht. Pityrosporum canis und Staphylokokken waren die am häufigsten abgesonderten Lebewesen. Ihr Vorkommen war bei klinisch betroffenen Ohren viel größer als bei normalen Ohren. Gram-negative Lebewesen wurden nur in kranken Ohren vorgefunden. Dreiundsiebenzig klinische Fälle von Otitis bei Hunden und Katzen wurden mit einem Präparat behandelt, das Neomycin, Monosulfiram und Betamethasone enthielt. Bakteriologische und klinische Bewertungen wurden vor und nach Behandlung durchgeführt, und die abgesonderten Lebewesen wurden auf Empfindlichkeit gegen mikrobenbetreffende Bestandteile des Präparates geprüft. Zwischen den bakteriologischen und klinischen Ergebnissen bestand eine 92 prozentige Wechselbeziehung. Eine “gute” oder “sehr gute” bakteriologische Reaktion wurde an 71% der behandelten Ohren festgestellt.     

Study of lipid in the ear canal in canine otitis externa with Malassezia pachydermatis

An epidemiological investigation of 120 canine otitis externa cases in 1,370 dogs was done on the incidence rate, ear pinna shapes, breeds and their relationships. Eighty-five cases (12.6%) in 672 dogs with pendulous ears and 35 cases (5.0%) in 698 dogs with erect ears had otitis externa, and the difference between them was significant (P<0.05). Ninety-five auditory cerumen specimens were cultured for Malassezia pachydermatis (M. pachydermatis) and analyzed for concentrations of major fatty acids. Although rates of cases positive for M. pachydermatis in both ear pinna shapes were almost the same, i.e. 55.2% in the pendulous group and 53.6% in the erect group, the average total fatty acid level of the pendulous ear group was significantly (P<0.05) higher than that in the erect ear group after dismissing extraordinary levels in the Siberian husky. Isolated M. pachydermatis strains were examined for the effects of fatty acid supplementation on their growth. The majority of the strains utilized fatty acids and grew faster in fatty acid supplemented broth. These results suggest that M. pachydermatis, the predominant causative agent of canine otitis externa, prefers the auditory canal of dogs with lipid-rich earwax and grows fast, but growth strongly depends upon the canine breed.     

Attachment of Malassezia pachydermatis to the ear dermal cells in canine otitis externa.

To investigate the predominance of Malassezia pachydermatis (M. pachydermatis) as a causative agent of canine otitis externa, ear cerumen samples were observed for adhesion of M. pachydermatis to the cornified epithelial cells by light and electron microscopes. The yeasts appeared not to adhere to the cornified epithelial cells directly, but they seemed to exist in the proximity of the epithelial cells with an electron opaque halo-like space around them. Polysaccharide and lipid staining techniques were conducted to identify the substances existing in that space. Lipid substances, not saccharides, were observed around the yeasts and the cornified epithelial cells. These results suggested that in the canine ear canal malassezia yeast attachment to the cornified epithelial cells is mediated by lipids.