Prevalence and in vitro antifungal susceptibility of commensal yeasts in the external ear canal of cats

Abstract Background Lifestyle factors such as hair length, the frequency of ear cleaning and bathing, age, cat rearing, and sex may contribute to opportunistic yeast infections in the external ear canal of cats. This study aimed to determine the prevalence of commensal yeast organisms in cats’ external ear canals, evaluate their predisposing lifestyle factors, and test the susceptibility of Malassezia pachydermatis to antifungal agents. Results A total of 53 cats (33 male and 20 female) seronegative for feline leukemia virus and feline immunodeficiency virus were enrolled in this study. Their mean age (± standard deviation) was 6.04 (± 3.49) years. Fungal cultures and polymerase chain reaction tests were performed to identify the yeast species derived from the external ear canal. The association between lifestyle factors and the presence of M. pachydermatis was evaluated using Fisher’s exact test. The susceptibility of M. pachydermatis to antifungal agents was also analyzed. M. pachydermatis was the most frequently recovered yeast species, with a prevalence of 50.94 % (95 % confidence interval [CI]: 36.84–64.94 %). There was an association between hair length and a positive culture for M. pachydermatis (p = 0.0001). The odds of a negative culture for M. pachydermatis among short-haired cats was 11.67 (95 % CI, 3.22–42.24) times higher than that among long-haired cats (p = 0.0002). There was also an association between the frequency of ear cleaning and the presence of M. pachydermatis (p = 0.007). The odds of a negative culture for M. pachydermatis in cats that were receiving ear cleaning at intervals of ≤ 2 weeks was 5.78 (95 % CI, 1.67–19.94) times greater than that of cats receiving ear cleaning at intervals greater than 2 weeks or never (p = 0.0055). Ranges of minimum inhibitory concentrations (MICs) and minimum fungicidal concentrations for itraconazole, ketoconazole, miconazole, and terbinafine against M. pachydermatis were ≤ 0.063–4 and ≤ 0.063–≥32, ≤ 0.063–8 and 0.125–≥32, ≤ 0.063–≥32 and 0.5–≥32, and ≤ 0.016–1 and 0.125–8 µg/ml, respectively. Conclusions M. pachydermatis was the most commonly identified yeast organism in the external ear canal of healthy cats. Hair length and the frequency of ear cleaning played a role in the colonization of M. pachydermatis. The M. pachydermatis isolates had various MIC levels for common fungicides.

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Occurrence and identification of yeasts in dogs external ear canal with and without otitis

Revista Mvz Córdoba ◽

10.21897/rmvz.242 ◽

2012 ◽

pp. 3059-3064 ◽

Cited By ~ 1

Author(s):

Elidiana De Bona ◽

Sergio Ubiratan Paz Telesca ◽

Alexandre Meneghello Fuentefria

Keyword(s):

Immune System ◽

Tissue Injury ◽

External Ear ◽

Ear Canal ◽

Malassezia Pachydermatis ◽

Veterinary Clinic ◽

Strong Activity ◽

High Proteolytic Activity ◽

External Ear Canal ◽

Different Response

ABSTRACTObjective. To analyze the presence of yeast in the external ear canal of 116 dogs with and without a diagnosis of otitis from veterinary clinic in the Chapecó city, Santa Catarina, Brazil, and to examine the secretion of the proteinase in isolates. Materials and methods. Were collected cerumen of conduct hearing of dogs of 16 different races 71% with pendular ear type, 5% of semi-pendular and 24% of the erect type. All dogs were previously evaluated by otoscopy and grouped in dogs with and without otitis. Results. Yeasts were isolated in 44 samples (approximately 36%), where Malassezia pachydermatis was identified in 95% of samples where were observed growth of yeasts. On 20 samples the proteinase enzyme showed strong activity in 31% isolates, were 21% of the dogs with otitis tested showed high proteolytic activity. Conclusions. We observed a variation of strains of M. pachydermatis-producing enzymes. The variation in production of these enzymes is probably more associated with different response to the action of the immune system of the animal in the tissue injury.

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Antifungal Susceptibility of Malassezia pachydermatis Isolates from Dogs

Folia Veterinaria ◽

10.2478/fv-2019-0013 ◽

2019 ◽

Vol 63 (2) ◽

pp. 15-20

Author(s):

Z. Sihelská ◽

E. Čonková ◽

P. Váczi ◽

M. Harčárová

Keyword(s):

Antifungal Agents ◽

Antifungal Susceptibility ◽

Diffusion Method ◽

Opportunistic Pathogens ◽

Ear Canal ◽

Disk Diffusion Method ◽

Malassezia Pachydermatis ◽

Resistant Strains ◽

Standard Disk

Abstract The genus Malassezia belongs to Basidiomycota and includes 16 species, from which M. pachydermatis is the most common in dogs. M. pachydermatis is a member of the normal mycobiota of the skin and mucosal sites of dogs. Under certain conditions, these yeasts can be opportunistic pathogens and involved skin and ear canal infections of these animals. Topical and oral antifungal agents are used for the therapy of Malassezia dermatitis and otitis. With the expanding use of antifungal agents, resistant strains of Malassezia are increasingly detected. In this study, the susceptibility of 40 M. pachydermatis isolates to fluconazole, itraconazole, ketoconazole, clotrimazole and nystatin were evaluated in vitro based on the modified standard disk diffusion method M44-2A.

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Isolation of Malassezia pachydermatis and M. sympodialis from the external ear canal of cats with and without otitis externa

Acta Veterinaria Hungarica ◽

10.1556/avet.55.2007.4.6 ◽

2007 ◽

Vol 55 (4) ◽

pp. 471-477 ◽

Cited By ~ 22

Author(s):

C. Dizotti ◽

Selene Coutinho

Keyword(s):

Otitis Externa ◽

False Negative ◽

Tween 20 ◽

External Ear ◽

Ear Canal ◽

Malassezia Pachydermatis ◽

External Ear Canal ◽

Negative Results ◽

Significant Difference ◽

The Difference

The objective of this study was to determine the presence of Malassezia spp. in the external ear canal of cats with and without otitis. Forty-five animals were studied, 20 with and 25 without otitis externa (OE). Cerumen or secretion from external ear canal samples was cultured on modified Mycosel agar and sterile olive oil was added to the surface of the medium before specimen seeding. The isolates were analysed for macro- and micromorphology and identified by catalase tests and on the basis of growth on Tween 20, 40, 60 and 80. Malassezia spp. were isolated from 15 out of 20 (75%) animals with otitis and from 7 out of 25 (28%) cats without OE; the difference between the two groups was statistically significant (P ≤ 0.05). Malassezia pachydermatis and M. sympodialis were isolated from 60% (12/20) and 40% (8/20) of cats with otitis, respectively, with no significant difference in the frequency of isolation between the two species. In the microflora of the healthy ear canal M. pachydermatis was significantly more common (6/25, 24%) than M. sympodialis (1/25, 4%). The present investigation confirms that M. sympodialis can also act as an aetiological agent of feline OE, and if commercial veterinary laboratories do not use media with added lipids for the isolation of Malassezia spp., this might lead to false-negative results.

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Quantification of Malassezia pachydermatis by real-time PCR in swabs from the external ear canal of dogs

Journal of Veterinary Diagnostic Investigation ◽

10.1177/1040638719840686 ◽

2019 ◽

Vol 31 (3) ◽

pp. 440-447 ◽

Cited By ~ 4

Author(s):

Laura Puig ◽

Gemma Castellá ◽

F. Javier Cabañes

Keyword(s):

High Specificity ◽

Single Copy ◽

Response To Treatment ◽

External Ear ◽

Ear Canal ◽

Limit Of Quantification ◽

Malassezia Pachydermatis ◽

Cytologic Examination ◽

External Ear Canal ◽

Low Sensitivity

Malassezia pachydermatis is part of the normal microbiota of canine skin and external ear canal, and is also associated with otitis externa in dogs. Laboratory detection of Malassezia otitis relies on the presence of elevated numbers of the yeast on cytologic examination of otic exudate. Although cytology has high specificity, it has low sensitivity, resulting in false-negatives and posing a challenge for clinicians to accurately diagnose Malassezia otitis. We developed a quantitative PCR (qPCR) to detect and quantify M. pachydermatis yeasts and validate the method with swabs from external ear canals of dogs. Our qPCR uses the β-tubulin gene, a single-copy gene, as a target. The limit of quantification was established as 0.18 ng/reaction, equivalent to 2.0 × 104 genome equivalents (gEq). Swabs from healthy dogs yielded quantification values of ≤2.7 × 104 gEq in the qPCR, whereas swabs from dogs with otitis yielded quantification values of ≥2.5 × 105 gEq. Our qPCR assay provides accurate quantification of M. pachydermatis yeasts from swab samples from dogs, is more sensitive than cytology, and could be used to monitor response to treatment. Our assay could also be valuable in a research setting to better understand the pathogenesis of M. pachydermatis.

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Rhabdomyosarcoma of the External Ear Canal Treated with Brachytherapy

West Virginia Medical Journal ◽

10.21885/wvmj.2016.20 ◽

2016 ◽

Vol 2016 (1) ◽

Cited By ~ 1

Author(s):

Mahvish Qureshi MD ◽

◽

Sana Farooki MD ◽

Chibuzo O’Suoji MD ◽

◽

...

Keyword(s):

External Ear ◽

Ear Canal ◽

External Ear Canal

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Prevalence of external ear disorders in Belgian stray cats

Journal of Feline Medicine and Surgery ◽

10.1177/1098612x17700808 ◽

2017 ◽

Vol 20 (2) ◽

pp. 149-154 ◽

Cited By ~ 3

Author(s):

Anouck Bollez ◽

Hilde de Rooster ◽

Alessandra Furcas ◽

Sophie Vandenabeele

Keyword(s):

Body Condition ◽

Otitis Externa ◽

Body Condition Score ◽

External Ear ◽

Ear Canal ◽

Malassezia Species ◽

External Ear Canal ◽

Stray Cats ◽

Condition Score ◽

Ocular Discharge

Objectives Feline otitis externa is a multifactorial dermatological disorder about which very little is known. The objective of this study was to map the prevalence of external ear canal disorders and the pathogens causing otitis externa in stray cats roaming around the region of Ghent, Belgium. Methods One hundred and thirty stray cats were randomly selected during a local trap–neuter–return programme. All cats were European Shorthairs. This study included clinical, otoscopic and cytological evaluation of both external ears of each cat. Prospective data used as parameters in this study included the sex, age and body condition score of each cat, as well as the presence of nasal and/or ocular discharge, and the results of feline immunodeficiency virus (FIV) and feline leukaemia virus (FeLV) Snap tests. Results Remarkably, very few (sub)clinical problems of the external ear canal were found in the stray cat population. Malassezia species was by far the most common organism found in the external ear canals of the 130 stray cats. A total of 96/130 (74%) cats were found to have Malassezia species organisms present in one or both ears based on the cytological examination. No correlation was found between the parameters of sex, age, body condition score, the presence of nasal and/or ocular discharge and FIV and FeLV status, and the presence of parasites, bacteria or yeasts. Conclusions and relevance This study provides more information about the normal state of the external ear canal of stray cats. The ears of most stray cats are relatively healthy. The presence of Malassezia species organisms in the external ear canal is not rare among stray cats.

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Prevalence of external auditory canal exostoses in Australian surfboard riders

The Journal of Laryngology & Otology ◽

10.1258/002221504323086525 ◽

2004 ◽

Vol 118 (5) ◽

pp. 348-351 ◽

Cited By ~ 35

Author(s):

William Hurst ◽

Michael Bailey ◽

Benjamin Hurst

Keyword(s):

External Auditory Canal ◽

Cold Water ◽

Control Group ◽

External Ear ◽

Ear Canal ◽

External Ear Canal ◽

Rate Of Growth

This paper assessed 300 surfboard riders, comprising 229 males and 71 females to determine the prevalence and rate of growth of exostoses in this population. A group of cold water swimmers and a control group were also examined. Significant obstruction, defined as two thirds or more occlusion of the ear canal was noted in 90 of the male surfers and 10 female surfers. This degree of occlusion was found in seven of the 32 cold water swimmers. A male surfer who has surfed regularly for 20 years or more has a one in two chance of developing significant obstruction of the external ear canal resulting from exostoses and this is a three in seven chance for females.

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Histopathology of the soft parts in 50 patients with malignant external otitis

The Journal of Laryngology & Otology ◽

10.1017/s0022215100108977 ◽

1989 ◽

Vol 103 (4) ◽

pp. 366-368 ◽

Cited By ~ 21

Author(s):

J. Bernheim ◽

J. Sade

Keyword(s):

Skin Lesions ◽

External Otitis ◽

Pathological Feature ◽

External Ear ◽

Ear Canal ◽

Malignant External Otitis ◽

External Ear Canal ◽

External Canal ◽

Skin Biopsies ◽

Skin Coverage

AbstractReports concerning the lesions of the skin coverage of the external ear canal in malignant external otitis (M.E.O.) are very few. To evaluate this problem, we studied the skin lesions of 45 skin biopsies from 40 M.E.O. patients, 23 from regions covering the osseous part of the ear structure, seven from the cartilaginous part of the external canal and 15 from both parts. The epidermis was normal in nine, thickened in 16, with acanthotic thickening and pseudoepitheliomatous hyperplasia in 20. In the dermis the amount of collagen was normal, but it was infiltrated by the inflammatory process. Acute inflammation was observed in 16 biopsies, subacute in 23, chronic in six. A mixture of acute and chronic changes was present in 18 biopsies. No major abnormalities of the vasculature could be detected. The distinguishing pathological feature of M.E.O. concerns the typical topographic distribution of the inflammation in the osseous part of the external ear canal.

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