Estudo das características fenotípicas, fatores de patogenicidade e suscetibilidade de isolados de Sporothrix schenckii frente a desinfetantes

• Main Author: Madrid, Isabel Martins
• Publication Date: 2011
• Format: Doctoral thesis
• Language: por
• Source: Repositório Institucional da UFPel - Guaiaca
• Download full: http://repositorio.ufpel.edu.br/handle/ri/2561
• topic: Veterinária; Esporotricose; Patogenicidade; Morfologia; Atividade antifúngica; Testes de suscetibilidade; Veterinary; Sporotrichosis; Pathogenicity; Morphology; Antifungal activity; Susceptibility tests; CNPQ::CIENCIAS AGRARIAS::MEDICINA VETERINARIA::PATOLOGIA ANIMAL

Sporotrichosis has been receiving attention in any world in the several areas of the health as an important fungal disease. So, this work aimed: (i) to study cases of sporotrichosis diagnosed in the south region of Rio Grande do Sul in a period of ten years, (ii) to study the morphological and pathogenicity characteristics of S. schenckii isolates, (iii) to determine the sensitivity of S. schenckii isolates to the commercial disinfectants. Sporotrichosis cases were analysed as for geographical distribution, it clinical forms of the disease, presence of the fungus in different anatomical sites and tecidual inflammatory response. The 42 S. schenckii isolates originating from clinical cases, environment isolates and reference strains used in the phenotypic study were evaluated as for macromorphology in Sabouraud agar added of chloramphenicol, potato agar and ágar lactrimel, incubated 25ºC and 35ºC for 21 days. The micromorphology was analyzed in potato agar to 25ºC whereas the termotholerance was evaluated in ágar Sabouraud added of 1% yeast extract, incubated 41ºC for seven days. Ultraestructural study of nine clinical isolates and two reference strains of S. schenckii were carried by transmission electron microscopy. Susceptibility of 12 S. schenckii isolates to disinfectants was performed by the techniques of broth microdilution, agar diffusion and direct exposute test. The 103 cases of sporotrichosis in animals demonstrated that this is an endemic mycosis in the south region of Rio Grande do Sul being more frequent in young felines and adult dogs. The felines developed disseminated cutaneous form with more frequency. Therefore, in canines, the fixed cutaneous form was predominant though it has taken place in 18.2% of the dog to respiratory form with absence of cutaneous lesions. Research of the S. schenckii in nails, oral cavity, conjunctival mucosa, blood and testicles demonstrated high fungal positivity in samples of oral cavity (45.2%) and testicles (46.6%). The study of the hematological alterations related with the clinical form of the disease demonstrated that animals with the cutaneous fixed form of the mycosis do not present alterations in the blood count. However, animals with the cutaneous disseminated form develop important alterations characterized mainly for leucocytosis with neutrophilia and anaemia. Morphological analyzes of 42 clinical and environmental isolates of S. schenckii demonstrated macro and micromorphogical differences in the different culture medium utilized. In the thermotolerance evaluation 26.2% isolates were capable of growth at 41oC, specially isolates of feline sporotrichosis. The ultraestructural study showed presence of granules of melanin in all S. schenckii isolates of canine sporotrichosis and correlation among melanin and cell wall thickness. In vitro evaluation of disinfectants demonstrated chlorexidine digluconate antifungal activity in the microdilution broth and agar diffusion techniques and the sodium hypochlorite showed best performance in the direct exposure test. The presence of the organic matter interfered in the antifungal action of both disinfectants. Sodium hypochlorite showed better results with total elimination of the fungal load in the absence of organic matter and a reduction of 60 % of the fungal load in the presence of this.