Susceptibilidade antifúngica, produção de biofilme e caracterização do gene ALS3 em isolados de Candida albicans e não-albicans do hospital das clínicas, UNESP, Botucatu
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Data
2009-02-19
Autores
Nascimento, Ariane Cristina Mendes de Oliveira Bruder [UNESP]
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
Leveduras oportunistas do gênero Candida são capazes de disseminar-se em hospedeiros susceptíveis, num processo crescente nos últimos anos. Um fator complicador destes quadros ocorre quando estas leveduras são capazes de produzir biofilme, principalmente quando associadas a cateteres ou outros dispositivos médicos, elevando o poder de penetração e invasão em órgãos do hospedeiro. Por também conferir maior resistência às drogas antifúngicas do que as células dispersas, o biofilme fúngico tornou-se um dos maiores problemas no combate a estas infecções. A base genética da produção de biofimes nestas leveduras é complexa, porém já foi determinado o envolvimento de genes da família ALS, codificadores de glicoproteínas de adesão. Dentre os oito genes desta família (ALS1 ao ALS7 e ALS9), destaca-se o papel de ALS3. O gene ALS3, assim como todos os outros genes da família, apresenta uma estrutura composta por 3 domínios. O domínio 5’, região bem conservada; um domínio central que apresenta motifs de 108pb repetidos em tandem, com variações de tamanho entre os genes da mesma família e entre o mesmo gene em diferentes espécies, em uma mesma espécie e até mesmo entre alelos de uma mesma cepa, e o domínio 3, menos conservado que o domínio 5’, que pode apresentar variações de tamanho e de algumas seqüências de aminoácidos. Tendo em vista a crescente incidência de infecções por esse microrganismo em todo o mundo, o presente estudo objetivou investigar a freqüência das diferentes espécies de Candida em nossa região e caracterizá-las quanto à susceptibilidade a drogas antifúngicas e produção de biofilme, e possível correlação da produção de biofilme com polimorfismos de tamanho do gene ALS3. Os resultados obtidos confirmam a crescente incidência de espécies não-albicans, principalmente isoladas de infecções invasivas como cultura...
Opportunistic yeasts of the genus Candida are able to disseminate into the bloodstream in susceptible hosts, in an increasing course in the recent years. A complicating factor is when these yeasts are capable of producing biofilms, especially associated with catheters or other medical devices. Biofilm also confers greater resistance to antifungal drugs than dispersed cells, so the fungal biofilm has become one of the greatest problems in combating these infections. The genetic basis of the biofim production by yeasts is complex, but it has been know the involvement of ALS gene family, encoders of adhesion glycoproteins. Among the eight genes of this family (ALS1 to ALS7 and ALS9), the ALS3 are considered the most important. The ALS3 gene, such as the others members of the family, have three general domains: the 5’domain, conserved, with approximately 1300-pb; followed by a central domain consisting entirely of tandem-repeats of a 108-pb sequence, that are somewhat variable; and the 3’ domain, which is least conserved in length and sequence. Considering the increase incidence of these infections worldwide, the aims of this study were identify the frequency of Candida species in our region, to characterize the profile of antifungal susceptibility; to quantify the biofilm production and to correlate this production with the ALS3 gene length polymorphism. Our data confirm the increase incidence of non-albicans species, mainly when obtained from invasive infections, such as blood and peritoneal fluid, in which C. parapsilosis was the most frequent isolated species. The same was also observed to biofilm production, in which isolates obtained from invasive infections (blood and peritoneal fluid) are more biofilm producers than that obtained from vaginal secretion and urine. Among the different species, isolates of non-albicans also are more biofilm producers than C. albicans. Polimerase... (Complete abstract click electronic access below)
Opportunistic yeasts of the genus Candida are able to disseminate into the bloodstream in susceptible hosts, in an increasing course in the recent years. A complicating factor is when these yeasts are capable of producing biofilms, especially associated with catheters or other medical devices. Biofilm also confers greater resistance to antifungal drugs than dispersed cells, so the fungal biofilm has become one of the greatest problems in combating these infections. The genetic basis of the biofim production by yeasts is complex, but it has been know the involvement of ALS gene family, encoders of adhesion glycoproteins. Among the eight genes of this family (ALS1 to ALS7 and ALS9), the ALS3 are considered the most important. The ALS3 gene, such as the others members of the family, have three general domains: the 5’domain, conserved, with approximately 1300-pb; followed by a central domain consisting entirely of tandem-repeats of a 108-pb sequence, that are somewhat variable; and the 3’ domain, which is least conserved in length and sequence. Considering the increase incidence of these infections worldwide, the aims of this study were identify the frequency of Candida species in our region, to characterize the profile of antifungal susceptibility; to quantify the biofilm production and to correlate this production with the ALS3 gene length polymorphism. Our data confirm the increase incidence of non-albicans species, mainly when obtained from invasive infections, such as blood and peritoneal fluid, in which C. parapsilosis was the most frequent isolated species. The same was also observed to biofilm production, in which isolates obtained from invasive infections (blood and peritoneal fluid) are more biofilm producers than that obtained from vaginal secretion and urine. Among the different species, isolates of non-albicans also are more biofilm producers than C. albicans. Polimerase... (Complete abstract click electronic access below)
Descrição
Palavras-chave
Candida albicans, Infeccão hospitalar, Biofilme (Microbiologia), Hospital infection
Como citar
NASCIMENTO, Ariane Cristina Mendes de Oliveira Bruder. Susceptibilidade antifúngica, produção de biofilme e caracterização do gene ALS3 em isolados de Candida albicans e não-albicans do hospital das clínicas, UNESP, Botucatu. 2009. 69 f. Dissertação (mestrado) - Universidade Estadual Paulista, Instituto de Biociências de Botucatu, 2009.