Infecções oportunistas por leveduras e perfil enzimático dos agentes etiológicos / Opportunistic yeast infections and enzymatic profile of the etiological agents

Infecções por leveduras são freqüentes em imunocomprometidos, contudo espécies emergentes têm alterado o perfil epidemiológico. A habilidade de secretar proteases tem sido associada à patogenicidade do gênero Candida. Esta pesquisa teve como objetivos diagnosticar leveduroses em pacientes imunocomprometidos e avaliar a virulência dos agentes etiológicos baseado em teste de secreção de protease utilizando soro de albumina bovina como substrato. Do total de 104 pacientes estudados, 19 apresentaram episódios de leveduroses. O trato respiratório (63,2 por cento), seguido pelo trato urinário (10,5 por cento) foram os locais mais comuns de infecção. Candida albicans, Candida parapsilosis, Candida tropicalis e espécies emergentes como Candida krusei e Candida guilliermondii foram isoladas. Cinco isolados de Candida parapsilosis e um de Candida albicans e Candida guilliermondii exibiram alta atividade enzimática. Concluímos que a caracterização enzimática de isolados de Candida pode ser um útil marcador prognóstico, especialmente em imunocomprometidos, uma vez que leveduroses nestes pacientes são geralmente graves.

Yeast infections are common in immunocompromised patients, although emerging species have been changing the epidemiological profile. The ability to secrete proteinases has been associated with pathogenicity within the genus Candida. This study had the aims of diagnosing yeast infections in immunocompromised patients and evaluating the virulence of the etiological agents, based on a proteinase secretion assay using bovine serum albumin as a substrate. Out of a total of 104 patients studied, 19 presented episodes of yeast infection. The respiratory tract (63.2 percent), followed by the urinary tract (10.5 percent), were the most common sites of infection. Candida albicans, Candida parapsilosis, Candida tropicalis and emerging species such as Candida krusei and Candida guilliermondii were isolated. Five isolates of Candida parapsilosis and one of Candida albicans and Candida guilliermondii exhibited high enzymatic activity. We conclude that enzymatic characterization of Candida isolates may be a useful prognostic marker, especially among immunocompromised individuals, since yeast infections in such patients are generally serious.

Antagonistic effect of edible mushroom extract on Candida Albicans growth

Five species of edible mushrooms, Lentinula edodes, Pleurotus ostreatus, Pholiota nameko, Macrolepiota bonaerensis and Agaricus blazei, were tested for their potential to inhibit the in vitro growth of the pathogenic yeast Candida albicans. Only L. edodes had a fungistatic effect on this human pathogen. The inhibitory compound was produced intra and extracellularly in submersed L. edodes culture, and was also present in fresh and dehydrated mushroom basidiocarps. The fungistatic compound was heat sensitive and lost activity after 72 hours.

Seroreactivities of proteinases of Candida albicans, C. tropicalis, and C. parapsilosis in sera from various Candida species-infected mice

From the culture filtrates of C. albicans, C. tropicalis and C. parapsilosis, proteinases were purified using a series of chromatographic steps consisting of DEAE-Sepharose, Sephacryl S-200 and size-exclusion HPLC which removed contaminating mannoproteins and extraneous proteins. Anti-Candida proteinase antibodies in sera from mice infected with various Candida species were detected using ELISA for serodiagnosis of candidiasis. Three proteinases were blotted by homologous and heterologous anti-proteinase antisera on Western blot analysis. All sera from six Candida species-infected mice were reactive with proteinases of C. albicans, C. tropicalis, and C. parapsilosis, although C. glabrata, C. guilliermondii, and C. krusei did not secrete proteinase. The seroreactivities of proteinase with sera from mice infected with homologous C. albicans and C. tropicalis were higher than those with sera from heterologous Candida species-infected mice. These results suggest that three proteinases have at least one common epitope, but its application for diagnosis of candidiasis should be considered with limits of specificity.