Fatores de virulência de isolados de Candida de pacientes imunocomprometidos. Caracterização molecular de Candida albicans suscetíveis e resistentes ao fluconazol

• Autor(a) principal: COSTA, Carolina Rodrigues
• Data de Publicação: 2009
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: Biblioteca Digital de Teses e Dissertações da UFG
• Texto Completo: http://repositorio.bc.ufg.br/tede/handle/tde/1560
• topic: Candida albicans, fatores de virulência, pacientes imunocomprometidos, características moleculares; Candida albicans, virulence factors, immunocompromised patients, molecular characteristics; CNPQ::CIENCIAS BIOLOGICAS::MICROBIOLOGIA

Adhesion to host tissues, production of hydrolytic enzymes, the resistance to antifungals and ability to production hyphal interfere in the infectious process caused by Candida. Resistance to azole antifungal agents, used to treatment of candidiasis, has been observed to immunocompromised patients. Molecular typing based on RAPD-PCR has been used to discriminate between susceptible and resistant isolates to antifungal agents. In this work, were evaluated the virulence factors and molecular characteristics of Candida isolates obtained of samples from blood, catheter of nosocomial patients and from oral cavity of HIV positive patients. The isolates were identified as: Candida albicans (59) Candida parapsilosis (22), Candida tropicalis (14) Candida guilliermondii (07), Candida. famata (05), Candida krusei (03), Candid. lusitaniae (01) and Candida kefyr (01). The proteinase and phospholipase production and the adherence ability were determined for these yeasts. The effect of fluconazole and itraconazole antifungal agents on hyphal formation were studied to 5 isolates previously classified as either susceptible or resistant. The characterization genotypic of resistant and susceptible isolates to fluconazole was carried out for 13 isolates of C. albicans by RAPD-PCR method. The results showed that proteinase activity was detected in 88.1% of C. albicans isolates and in 69.8% of non C. albicans, while phospholipase was produced in 55.9% of C. albicans isolates and in 37.7% of non C. albicans. Isolates of blood were more proteolitic than catheter and oral cavity, while for phospholipase, there was more production of this enzyme in the oral cavity. The ability of adherence to buccal epithelial cell was higher in C. albicans than non C. albicans, however there was not behavior difference between the isolates from different sources studied. The hyphal formation was higher in resistant isolates than susceptible isolates when used the both drugs. In RAPD-PCR method the formation of two different groups was verified for susceptible and resistant isolates being that only one resistant isolate was clustered in the susceptible group. Thus, in this work, it was verified that the exoenzymes activity and adherence ability depend not only of the specie of Candida, but too of the source from host; the resistant isolates produced more hyphal than susceptible isolates under the antifungal action and the molecular characteristics of the resistant isolates did not suggest unique DNA fingerprints did not predicting their susceptibility to fluconazole