Isolamento, identificação e suscetibilidade in vitro de fungos causadores de onicomicose

• Ano de defesa: 2010
• Autor(a) principal: ATAÍDES, Fábio Silvestre
• Orientador(a): SILVA, Maria do Rosário Rodrigues
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Goiás
• Programa de Pós-Graduação: Mestrado em Medicina Tropical
• Departamento: Medicina
• País: BR
• Palavras-chave em Português: Candida spp; fungos filamentosos; susceptibilidade antifúgaica; epidemiologia
• Palavras-chave em Inglês: Candida spp; filamentous fungi; antifugal susceptibility; epidemiology
• Área do conhecimento CNPq: CNPQ::CIENCIAS DA SAUDE::MEDICINA
• Link de acesso: http://repositorio.bc.ufg.br/tede/handle/tde/1809

Onychomycosis is the nail infection caused by a wide spectrum of fungi species, including yeasts, dermatophyte and filamentous fungi nondermatophytes (FFND). In this work, patients with lesions nails from Dermatology Department in Clinics Hospital of the Federal University of Goiás were studied. These patients were submitted to mycologic tests and the etiologic agents identified were evaluated on in vitro activity for systemic antifungal agents. During the period of March 2008 to March 2009, 114 patients clinically suspected of having onychomycosis were examinated. The nail samples collected were submitted to direct examination with potassium hydroxide 20% and grown in dextrose Sabouraud agar and specific fungal pathogens agar. The antifungal susceptibility test was performed according to the method of broth microdilution, recommended by the Clinical Laboratory Standards Institute (CLSI), through M38-A and M27-A2 documents. The onychomycosis diagnosis was established in 83.3% (95/114) patients, of which most were women between 40 to 59 years old. The isolated fungi were identified as yeasts in 54.6%; dermatophytes in 28.7%; and filamentous fungi nondermatophytes in 16.7%. Among yeasts, Candida parapsilosis was the most common etiologic agent (52.5%); among dermatophytes, Trichophyton rubrum was the most found (74.2), and among the filamentous fungi nondermatophytes, Fusarium spp was the most isolated genus (44.4%). Both distal and lateral subungual lesions were predominant in cases of onychomycosis by all the agents identified, showing that there was no correlation with the clinical presentation and etiology. Although most of the isolates have showed susceptible to several antifungal agents studied, five Candida spp strains were resistant; one to voriconazole, one species to itraconazole and three to amphotericin B. The in vitro susceptibility testing profile for dermatophytes was similar for each antifungal agent analyzed. The minimal inhibitory concentration (MIC) of itraconazole, ketoconazole and griseofulvin for 50% of isolates were lower than 1 μg/mL, and terbinafine was extremely low, with concentration 0.015 μg/mL for 90% of isolates. The MIC for itraconazole in 90% isolates of FFND was 16 g/mL, while for amphotericin B and voriconazole was 8 g/mL. In summary, this study showed a higher frequency of onychomycosis in women. Candida spp and dermatophytes with FFND emergence, especially of the genus Fusarium, were the main fungi involved. Besides, the presence of resistant fungi to some antifungal agents showed the need of using susceptibility tests for these fungi.