Concordance between otic cytology and culture in diagnosis of external otitis canine by Malassezia spp

Abstract

Objective. To determine the correlation between microbiological culture and otic cytology for diagnoses of external otitis by Malassezia in dogs. Materials and methods. 158 ear swabs of dogs with clinical diagnosis of external otitis were analyzed by cytology, mycological culture and metabolic tests. Results. Were obtained a positive results by cytology of 62% and 75.3% by culture. The 31.1% of isolates were identified as M. pachydermatis, 12.6% as M. furfur and 56.3% were classified as Malassezia spp., because was not possible to define the species. We found a positive concordance between cytology and culture for Malassezia spp., of 0.76 with a kappa index of 0.448 (95% CI 0.30 to 0.60) which represents a moderate strength of concordance between the two techniques, without regard the identified species. Conclusions. The use of a diagnostic test is not enough to establish the participation of Malassezia spp., as a causal disease agent. Key words: Canis familiaris, diagnostic techniques, Malassezia, otitis externa (Source: CAB). RESUMENObjetivo. Determinar la concordancia entre el cultivo microbiológico y la citología ótica para el diagnóstico de otitis externa causada por Malassezia spp. en caninos. Materiales y métodos. Se analizaron 158 muestras de hisopados de caninos con diagnóstico clínico de otitis externa, todas las muestras fueron analizadas mediante citología, cultivo micológico y pruebas metabólicas. Resultados. Se obtuvo una positividad mediante citología del 62% y por cultivo del 75.3%. El 31.1% de los aislamientos fueron identificados como M. pachydermatis, el 12.6% como M. furfur y un 56.3% se clasificó como Malassezia spp., dado que bioquímicamente no fue posible hallar su especie. Se determinó una concordancia observada entre técnicas positivas para Malassezia spp. de 0.76 con índice Kappa de 0.448 IC 95% (0.30 -0.60) lo que representa una fuerza de concordancia moderada entre las dos técnicas, sin tener en cuenta la especie identificada. Conclusiones. El uso de una prueba diagnóstica no es suficiente para establecer la participación de Malassezia pachydermatis como agente causal de enfermedad.Palabras clave: Canis familiaris, técnicas diagnósticas, Malassezia, otitis externa (Fuente: CAB). ORIGINALRev. MVZ Córdoba 20(3):4720-4725, 2015.

A randomized placebo-controlled trial of the efficacy and safety of a terbinafine, florfenicol and betamethasone topical ear formulation in dogs for the treatment of bacterial and/or fungal otitis externa

“…That the main outcome measures focussed on clinical signs rather than cytology was deemed preferable as, even though cytology is perceived to be the “ gold standard ” for OE assessment, it is far from capturing the complex reality of the skin and ear microbiome of normal and allergic dogs [ 20 , 21 ]. Although cytology and clinical assessment are generally correlated in dogs with OE [ 22 ], it has not been possible to establish thresholds with sufficient sensitivity and specificity to allow the use of cytological endpoints in clinical studies [ 23 ]. Additionally, in this study, microbial culture was done before treatment, and culture and cytology results have been shown to generally correlate in dogs with either Malassezia [ 23 ] or microbial OE [ 9 ].…”

“…Although cytology and clinical assessment are generally correlated in dogs with OE [ 22 ], it has not been possible to establish thresholds with sufficient sensitivity and specificity to allow the use of cytological endpoints in clinical studies [ 23 ]. Additionally, in this study, microbial culture was done before treatment, and culture and cytology results have been shown to generally correlate in dogs with either Malassezia [ 23 ] or microbial OE [ 9 ].…”

Prevalence of external ear disorders in Belgian stray cats

“…Cytology is a common method used for identifying Malassezia species. [9][10][11] All cytological samples were evaluated by the same person.…”

Genotyping of Malassezia pachydermatis disclosed genetic variation in isolates from dogs in Colombia

“…A total of 43 isolates of M. pachydermatis from dogs with clinical record of otitis externa from a previous study (Pulido et al 2010) were included. The isolates were phenotypically characterized, including the evaluation of phospholipase activity (Pulido-Villamarín et al 2015), preserved in 10% skin milk at -70 °C according to the methods for preservation and storage of Malassezia species (Crespo et al 2000), and deposited at the microorganism collection from the "Unidad de Investigaciones Agropecuarias" (UNIDIA, Unit of Agricultural Research) of the "Pontificia Universidad Javeriana". In addition, Malassezia strains: M. furfur CBS 7019, M. pachydermatis CBS 1879, M. sympodialis CBS 7222 and M. slooffiae CBS 7956, obtained from the Fungal Biodiversity Center (Westerdijk Institute, Utrecht, The Netherlands), were used as phenotypic and genotypic controls.…”

“…Malassezia pachydermatis is one of the most common species within this genus, which is commonly isolated from mammals and birds. In dogs, it is frequently found in the external ear canal; moreover, this species may cause otitis externa and dermatitis (chronic, localized or generalized, external lesions) (Crespo et al 2002, Bond et al 2010, Pulido et al 2010, Pulido-Villamarín et al 2015. Furthermore, M. pachydermatis has been considered to be potentially zoonotic, mainly associated to fungaemia (Gueho et al 1987, Morris et al 2005, Bond et al 2010, Seyedmousavi et al 2015.…”