Are polar extracts and essential oil from Origanum vulgare Linn. (oregano) an alternative against itraconazole-resistant dermatophytes from veterinary cases?

Although the conventional therapy against dermatophytosis is based on antifungal drugs and environmental disinfection, the emergence of itraconazole(ITZ)-resistant dermatophytes has encouraged the search for active compounds, such as Origanum vulgare L. (oregano) essential oil (EO). However, little is known about its effect in polar extracts or the mechanism of action of these extracts and EO. We investigated the antifungal activity of four polar extracts and one EO from oregano against ITZ-susceptible and ITZ-resistant dermatophytes and their action mechanism. Polar extracts were prepared as infusions at 10 (INF10) and 60 (INF60) minutes, decoction (DEC) and hydroalcoholic extract (HAE); EO was purchased. All extracts and itraconazole were tested against Microsporum gypseum, M. canis, M. nanum, Trichophyton mentagrophytes and T. verrucosum isolated from cats, dogs and cattle (n = 28), and humans (n = 2) (M38-A2, CLSI). Among polar extract, DEC stood out as antifungal, followed by INF10 and INF60; HAE was little active. For EO, all isolates were susceptible, including ITZ-resistant dermatophytes. EO was selected for action mechanism assays, and acted in cell wall and plasmatic membrane by complexing with fungal ergosterol. By chromatographic analysis, 4-hydroxibenzoic acid was the most prevalent compound in all polar extracts, followed by syringic acid and caffeic acid; luteolin was present only in HAE. For EO, carvacrol was the major compound (73.9%); followed by γ-terpinene (3.6%) and thymol (3.0%). These findings showed that the extract type of oregano has influenced the antifungal action on dermatophytes, highlight EO and DEC, that are promising as antifungal agent, including against ITZ-resistant dermatophytes.

Subcutaneous phaeohyphomycosis due to Aureobasidium pullulans infection in a dog

A case of subcutaneous phaeohyphomycosis in a dog with an ulcerative lesion on the right limb during a post-operative period of castration was described for the first time. The macroscopic and microscopic characteristics of the fungal colonies growth on the Sabouraud­dextrose agar were detailed. The fungus was identified as Aureobasidium pullulans on the basis of the phenotypic analysis, which was confirmed by sequencing of the internal transcribed spacers (ITS) region of rDNA. The patient might have acquired the infection through traumatic inoculation by environmental contact, along with the immunological condition during the stressful period of postoperative. The spontaneous remission of the lesion was observed in five weeks without antifungal treatment. This work highlights the importance of considering the pathogenic potential of this environmental fungus and the need of including it in the differential diagnosis of cutaneous lesions in dogs.

Susceptibility of dermatophytic fungi to commonly used disinfectants / Suscetibilidade de fungos dermatófitos a desinfetantes comumente utilizados

This study aimed evaluate the antidermatophytic activity of three commercial disinfectants commonly used for environmental control of microorganisms in veterinary medicine. Sodium hypochlorite at 40 µL/mL, chloro-phenol derived at 30 µL/mL and chlorhexidine digluconate at 66.7 µL/mL were tested against 14 strains of dermatophytes, identified as Microsporum canis (n: 3) and Microsporum gypseum (n: 11). The tests was performed in accordance with guidelines of the Clinical and Laboratory Standards Institute (CLSI), documents M38-A2 and M51-A, adapted to disinfectants. In the microdilution broth test, chlorhexidine digluconate had MIC values (Minimum Inhibitory Concentration) of 4.16 µL/mL and MCF (Minimum Fungicidal Concentration) from 4.16 to 8.33 µL/mL, while chloro-phenol derived obtained MIC and MCF of 1.87 µL/mL, and both disinfectants had fungicidal activity at concentrations below the recommended. Sodium hypochlorite obtained MIC from 10 to 80 µL/mL and MFC of 40 to 80 µL/mL, requiring at most isolates twice the recommended concentration to achieve same activity. In the disc diffusion test, the mean inhibition zones for chlorhexidine digluconate was 10.53 mm, for chloro-phenol of 9.9 mm and for sodium hypochlorite was 6.2 mm. Chlorhexidine digluconate and chloro-phenol presented a significant reduction in the growth of dermatophytes, while sodium hypochlorite in concentration recommended showed a low antifungal activity against tested isolates.

O objetivo do estudo foi avaliar a atividade antidermatofítica de três desinfetantes comerciais frequentemente utilizados no controle ambiental de micro-organismos em medicina veterinária. Hipoclorito de sódio a 40 µL/mL, derivado de clorofenol a 30 µL/mL e digluconato de clorexidine a 66.7 µL/mL foram testados contra 14 cepas de dermatófitos, identificados como Microsporum canis (n: 3) e Microsporum gypseum (n: 11). Foram utilizadas as diretrizes do Clinical and Laboratory Standard Institute (CLSI), documentos M38-A2 e M51-A, com adaptações para desinfetantes. Na microdiluição em caldo, digluconato de clorexidine apresentou valores de CIM (Concentração Inibitória Mínima) de 4.16 µL/mL e CFM (Concentração Fungicida Mínima) entre 4.16 a 8.33 µL/mL; derivado de clorofenol obteve CIM e CFM de 1.87 µL/mL, demonstrando que ambos os desinfetantes apresentaram atividade fungicida em concentrações inferiores às recomendadas. O hipoclorito de sódio demonstrou CIM entre 10 a 80 µL/mL e CFM de 40 a 80 µL/mL, requerendo duas vezes a concentração recomendada pelo fabricante para obter atividade fungicida frente a maioria dos isolados fúngicos testados. No teste de disco-difusão, a média das zonas de inibição do digluconato de clorexidine foi de 10.53 mm; do derivado clorofenol 9.9 mm e do hipoclorito de sódio 6.2 mm. O digluconato de clorexidine e o derivado cloro-fenol apresentaram redução significante no crescimento dos dermatófitos testados, enquanto o hipoclorito de sódio, na concentração recomendada, demonstrou baixa atividade antifúngica contra os dermatófitos testados.

Microsporose mista canina - relato e caso / Microporosis mixta canina ? relato de caso / Canine mcrosporose mixed - case report

Dermatofitoses são micoses causadas por fungos como: Epidermophyton, Microsporum e Trichophyton. M. canis e M. gypseum são os principais responsáveis pelas infecções dermatofíticas em pequenos animais e acometem principalmente animais jovens. Essas micoses cursam com lesões nas camadas queratinizadas da pele e pelos e em infecções mistas, a intensidade das lesões pode ser aumentada, pois os agentes causais atuam potencializando o quadro clínico. Descreve-se um caso de microsporose mista canina em um filhote de cão da raça Rottweiler. Um canino da raça Rottweiller atendido em uma clínica particular, pois apresentava lesões alopécicas e descamativas em diferentes sítios do corpo. Foi realizada coleta por meio de raspado cutâneo e o material foi encaminhado para exame micológico. O exame direto do pelo revelou estruturas características de dermatofitose com hifas artrosporadas e aglomerados de artroconídeos. O cultivo micológico resultou em crescimento de colônias fúngicas sugestivas de M. gypseum e M. canis nos meios de cultura semeados com confirmação das características macro e micromorfológicas das duas diferentes espécies fúngicas. Assim, mediante processamento micológico estabeleceu-se, juntamente com o histórico do caso, o diagnóstico de microsporose mista canina. Desse modo, conclui-se a necessidade de exames laboratoriais para a confirmação do diagnóstico definitivo de dermatofitose, sendo a profilaxia, prevenção, controle e potencial zoonótico dessa micose dependente da espécie infectante, tendo importância o seu controle também por seu impacto em saúde pública.

Dermatophytosis mycoses are caused by fungi such as Epidermophyton, Microsporum and Trichophyton. M. canis and M. gypseum are the main responsible for dermatophytic infections in small animals and affect mainly young animals. These mycoses occur with lesions in the keratinized layers of the skin and the mixed infections and the intensity of the lesions can be increased because the causative agents act enhancing the clinical picture. We describe a case of mixed microsporose dog in a puppy dog breed Rottweiler. A canine breed Rottweiller served in a private clinic because he had alopecia, scaly lesions at different body sites. It was collected through skin scrapings and the material was sent for mycological examination. Direct examination of the structures revealed by the characteristics of dermatophytosis with of hyphae artrosporadas and arthroconidia clusters. The mycological cultivation resulted in growth of fungal colonies suggestive of M. canis and M. gypseum in culture media seeded with confirmation of macro and micromorphological characteristics of the two different fungal species. Thus, by processing mycological established together with the case history, the diagnosis of canine microsporose mixed. Through the described case is concluded the need for laboratory tests to confirm the definitive diagnosis of dermatophytosis and prophylaxis, prevention, control and zoonotic potential of this mycosis dependent on the infecting species, taking control of the same importance also for their impact on public health.

Dermatofitosis son micosis causadas por hongos como: Epidermophyton, Microsporum y Trichophyton. M.canis y M. gypseum que son los principales responsables en las infecciones por dermatofitos en animales pequeños y afectan principalmente animales jóvenes. Esas micosis se producen con lesiones en las capas queratinizadas de la piel, pelos y en infecciones mixtas, la intensidad de las lesiones puede ser aumentada, pues los agentes causantes actúan potencializando el cuadro clínico. Se describe un caso de microsporosis mixta canina en un cachorro de perro de la raza Rottweiller. Un canino de la raza Rottweiller atendido en una clínica privada que presentaba lesiones de alopecia y lesiones escamosas en diferentes partes del cuerpo. Se realizó recolección por medio de raspado cutáneo y el material fue enviado para examen micológico. El examen directo del pelo reveló estructuras características de dermatofitosis hifas artrosporadas y aglomerados de artroconidios. El cultivo micológico resultó en crecimiento de colonias fúngicas sugestivas de M. gypseum y M canis en los medios de cultura sembrados, con confirmación de características macro y micro morfológicas de dos especies fúngicas. Así, mediante procesamiento micológico establecido junto con el histórico del caso, el diagnóstico de microsporosis mixta canina. Se concluye la necesidad de exámenes de laboratorio para confirmación del diagnóstico definitivo de dermatofitosis, siendo que la profilaxis, prevención, control y potencial zoonótico de esa micosis depende de la especie infectante, siendo importante su control por el impacto que causa a la salud pública.