A semiquantitative cytological evaluation of normal and pathological samples from the external ear canal of dogs and cats

Abstract

Numbers of desquamated epithelial cells, yeast cells and bacterial organisms were counted in samples collected from the external ear canal of 37 normal dogs and 16 normal cats, and from 24 dogs and 22 cats with otitis externa. The aims of the study were to establish quantitative reference ranges and to correlate these data with the clinical status of the dogs and cats. Numbers of yeast cells and bacterial organisms were significantly increased in dogs (P = 0.05; P = 0.0001) and cats (P = 0.0001; P = 0.0001) with otitis externa, and in most cases high counts were correlated with clinical signs. Mean Malassezia counts per high-power dry field of > or = 5 in the dog and > or = 12 in the cat were considered abnormal. Mean bacterial counts per high-power dry field of > or = 25 in the dog and > or = 15 in the cat were considered abnormal. When used to differentiate normal from inflamed external ear canals, these figures provided a low sensitivity but a specificity of > or = 95%.

Cytological Features of the Normal Ear Canal of Wild Jackals (<i>Canis aureus</i>) and Domesticated Dogs (<i>C. domesticus</i>)

“…These anatomical variations, however, are not present in jackals. In this report the dogs had similar presence of bacteria and yeasts in their normal ear canals as reported previously [5][6][7][8]. The most unexpected results were the significantly higher presence of bacteria in the jackals' ears.…”

“…The most common microorganisms isolated from the ears include the bacteria, Staphylococcus intermedius (now reclassified as Staphylococcus pseudintermedius), Pseudomonas aeruginosa, andProteus species, and yeasts such as Malassezia pachydermatis [2][3][4][5]. Most of the microorganisms isolated from inflamed ears are found in smaller numbers in normal ears [5][6][7][8][9]. In the dog, primary causes and predisposing factors, such as allergies, keratinization disorders and anatomical abnormalities, create suitable conditions for the proliferation of microorganisms [9,10].…”

Perfil clínico e microbiológico de cães com e sem otoacaríase

“…Não se deve confiar apenas na cultura para a determinação da verdadeira significância de infecções por bactérias e leveduras porque orelhas normais e inflamadas podem albergar os mesmos microrganismos, especialmente em infecções agudas (August, 1988;Ginel et al, 2002). Uchida et al (1990) no Japão, que observou alta prevalência de estafilococos coagulase negativa em cães sadios e com otite externa, assim como Nobre et al (1998) …”

“…Já o exame citológico oferece importante informação sobre a quantidade e a participação dos microrganismos nas otopatias, enquanto a cultura os identifica e ainda possibilita a execução de testes para determinação do tratamento adequado (Ginel et al, 2002;Tater et al, 2003). Os microrganismos mais frequentemente isolados do conduto auditivo de cães são Staphylococcus intermedius e Malassezia pachydermatis, embora vários outros também já tenham sido descritos (Oliveira et al, 2008).…”

Prevalence and commonest causes for otitis externa in dogs from two polish veterinary clinics

“…In the studies of these authors, the most commonly affected dogs were German shepherds (20%), followed by mongrels (14%), Labrador retrievers (8%) and Yorkshire terriers (2%). According to the numerous reports, the list of breeds suffering from otitis externa is quite extensive (Ginel et al, 2002;Topala et al, 2007;Taszkun, 2013a) with most commonly affected breeds such as the French and English bulldog, various terriers (chiefly the American Staffordshire terrier), Boxer, German shepherd, Dachshund, Labrador Retriever, Golden Retriever, Basset or Setter. These are the breeds with an increased number of sebaceous and ceruminous glands, which may cause moistening in the entire auditory meatus and lead to inflammations.…”