Caracterização de biofilmes polimicrobianos de Candida parapsilosis com Staphylococcus aureus ou Acinetobacter sp. e avaliação de sua sensibilidade a sanitizantes e a antimicrobianos

• Autor(a) principal: Mattiello , Shaiana Paula
• Data de Publicação: 2015
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Biblioteca Digital de Teses e Dissertações da PUC_RS
• Texto Completo: http://tede2.pucrs.br/tede2/handle/tede/6332
• topic: BIOLOGIA MOLECULAR; BIOLOGIA CELULAR; BACTÉRIAS; AGENTES ANTIBACTERIANOS; PREPARAÇÕES FARMACÊUTICAS; ENZIMAS - FARMACOLOGIA; BIOFILMES; CIENCIAS BIOLOGICAS::BIOLOGIA GERAL

The species of the “C. parapsilosis complex” are common etiological agents of nosocomial candidemia, and C. parapsilosis sensu stricto is one of non-albicans Candida species with the highest incidences in clinical infections, primarily related to implanted medical devices. In this study, we identified 29 isolates comprising the “C. parapsilosis complex” to species level, all previously obtained from the hospital environment and medical tools. The isolates were also characterized for in vitro activity of aspartyl proteinase and phospholipase, as well as for their ability to form biofilms. The isolates identified as C. parapsilosis sensu stricto were also evaluated for their capability to interact with Staphylococcus aureus and Acinetobacter sp. in two-species polymicrobial biofilms. These biofilms were then analyzed for their tolerance to treatments with increasing concentrations of antimicrobials drugs and sanitizers. The results indicated that 75.9% of the isolates were identified as C. parapsilosis sensu stricto, 24.1% as Candida metapsilosis and none as Candida orthopsilosis. Regarding C. parapsilosis sensu stricto, all isolates were very strong producers of aspartyl proteinase, and 13.6% of phospholipase. Regarding C. metapsilosis, 71.4% and 14.3% of the isolates showed very strong aspartyl proteinase and phospholipase activity, respectively. Moreover, all isolates were able to form biofilm on polystyrene surface. Among the C. parapsilosis sensu stricto isolates, 9.1%, 45.4% and 45.4% were strong, moderate and weak biofilm producers, respectively. Regarding C. metapsilosis, 71.4% were moderate and 28.6% were weak biofilm producers.We also demonstrated that C. parapsilosis sensu stricto was capable of associating synergistically with both bacteria tested, since in polymicrobial biofilms a significantly higher number of bacterial cells adhered, compared to their own monomicrobial condition. However, bacterial cells did not interfere on the efficiency of yeast biofilm formation. When testing sanitizers, we showed that 70% ethyl alcohol and 1% sodium hypochlorite were effective to significantly decrease the number of viable cells, although they have not been able to eliminate the microbial populations of the biofilms. Our data also showed that the cells from all monomicrobial biofilms exhibited elevated tolerance to their respective antimicrobial drugs, at higher doses than their pre-determined minimal inhibitory concentration values. Nevertheless, biofilms of 6, 12 and 24 h of C. parapsilosis sensu stricto presented some decrease in cell viability to the treatment with ketoconazole, whereas 48 h biofilms were resistant to this antifungal. In polymicrobial biofilms, the bacterial cells did not affect the tolerance of yeast isolates to this antimicrobial. Conversely, S. aureus and Acinetobacter sp. cells were even more tolerant to the treatment with vancomycin and polymyxin B, respectively, when they were in polymicrobial biofilms, which was significantly different from their respective monomicrobial condition.The results from this work revealed the ability of “C. parapsilosis complex” isolates from nosocomial environment to express important virulence factors, as well as to interact synergistically with bacterial species of clinical importance. This data is clinically relevant, since such phenotypic features may represent an important risk in terms of nosocomial infection to hospitalized patients.