Microbiological diagnoses of chronic otitis externa in the dog.
ABSTRACT The microbiological characteristics of otic exudates from 26 dogs with chronic otitis externa was studied with special reference to the implication of yeasts in the aetiology of the disease. A high frequency of yeasts and Staphylococcus aureus were isolated, alone or in association. In reference to the yeasts, there was a clear predominance of the genus Candida (48% of the total yeasts). Malassezia (Pytirosporum) represented only 3% of the isolates. It can be concluded that yeasts have an important role in the pathogenicity of this disease. For the microbiological diagnosis of otitis externa, we recommend the simultaneous use of Columbia/5% Sheep Blood Agar and Sabouraud-Dextrose without antibiotic addition, the use of 37 degrees C as the incubation temperature and direct microscopic observation of the sample before culture.
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ABSTRACT: Tacrolimus is a nonsteroidal alternative to treat noninfectious otitis externa (OE) in people. This 21-day study investigated whether twice daily application (0.2 mL/dose) of sterile olive oil based 0.1% tacrolimus suspension in ears of atopic beagle dogs without OE was associated with adverse local reactions, development of OE, change in otic cytology, vestibular dysfunction, or hearing loss detected by brainstem auditory evoked response (BAER). The study was randomized, double-blinded, and placebo-controlled. Twenty-two dogs matched for age and sex were randomized to tacrolimus or vehicle control treatment groups. Two investigators independently evaluated dogs for signs of adverse effects including OE the first 4 days of treatment, then every 3 days. A logistic regression model was fit for each investigator's clinical scores (SAS, 9.2, 2008). Time (P = 0.0032) and group (P = 0.0167) were always significant for OE. Inter-observer reliability of clinical scores was strong, measured using Kappa coefficients and proportion of agreement. All nine exclusions (7/10 control- and 2/12 tacrolimus-treated dogs) were excluded for yeast OE. Inter-observer agreement to exclude was 100%. All dogs not excluded had normal BAER assessments before treatment, weekly during treatment, and after 21 days of treatment. None showed vestibular abnormalities at these times. Tacrolimus blood concentrations (Abbott IMx Tacrolimus II) were below detection limits (3 ng/mL) at baseline and after 21 days of treatment. Results suggest otic application of olive oil based tacrolimus suspension to canine ears with intact tympanic membranes is unlikely to result in hearing loss or vestibular dysfunction but yeast OE is a possible risk.Veterinary Dermatology 12/2010; 21(6):554-65. · 1.99 Impact Factor
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ABSTRACT: This study aims to investigate the occurrence of coryneform bacteria in canine otitis externa. A combined case series and case-control study was carried out to improve the current knowledge on frequency and clinical significance of coryneform bacteria in samples from canine otitis externa. A total of 16 cases of otitis externa with involvement of coryneform bacteria were recorded at two referral veterinary hospitals in Denmark and the US, respectively. Coryneform bacteria were identified by partial 16S rRNA gene sequencing. Corynebacterium auriscanis was the most common coryneform species (10 cases). Small colony variants of this species were also observed. Other coryneform isolates were identified as Corynebacterium amycolatum (3 cases), Corynebacterium freneyi (2 cases) and an Arcanobacterium-like species (1 case). The coryneform bacteria were in all cases isolated together with other bacteria, mainly Staphylococcus pseudintermedius alone (n=5) or in combination with Malassezia pachydermatis (n=5). Some coryneform isolates displayed resistance to fusidic acid or enrofloxacin, two antimicrobial agents commonly used for the treatment of otitis externa in dogs. The frequency of isolation of coryneform bacteria was 16% among 55 cases of canine otitis externa examined at the Danish hospital during 2007. In contrast, detectable levels of coryneform bacteria were not demonstrated in samples from the acustic meatus of 35 dogs with apparently healthy ears, attending the hospital during the same year. On basis of the current knowledge, these coryneform bacteria should be regarded as potential secondary pathogens able to proliferate in the environment of an inflamed ear canal.Veterinary Microbiology 04/2010; 145(3-4):292-8. · 2.73 Impact Factor