Objective To investigate antifungal susceptibility and factors associated with oral colonization by Candida species in HIV-positive patients.Methods A prospective study based on convenience sampling of subjects recruited from a pool of confirmed HIV-positive individuals seen at a specialty outpatient service in Rondonópolis, Mato Grosso, Brazil). Oral swabs were collected from 197 patients. Candida species were identified by standard microbiological techniques (phenotypic and molecular methods). Antifungal susceptibility was investigated using the broth microdilution method.Results A total of 101 (51.3%) patients were Candida spp carriers. Candida albicans was the most prevalent species (80%). Patients aged 45 to 59 years (Prevalence ratios: 1.90; 95%CI: 1.57-6.31) and 60 years or older (Prevalence ratios: 4.43; 95%CI: 1.57-34.18) were at higher risk of oral colonization by Candida species. Resistance to fluconazole and ketoconazole, or to itraconazole, corresponded to 1% and 4%, respectively.Conclusion Age (45 years or older) was the only factor associated with oral colonization by Candida . Low rates of antifungal resistance to azoles were detected in yeast isolates obtained from HIV-positive patients. Findings of this study may contribute to proper therapeutic selection for oral candidiasis in HIV-positive patients.

Immobilization of cellulases on magnetic nanoparticles, especially magnetite nanoparticles, has been the main approach studied to make this enzyme, economically and industrially, more attractive. However, magnetite nanoparticles tend to agglomerate, are very reactive and easily oxidized in air, which has strong impact on their useful life. Thus, it is very important to provide proper surface coating to avoid the mentioned problems. This study aimed to investigate the immobilization of cellulase on magnetic nanoparticles encapsulated in polymeric nanospheres. The support was characterized in terms of morphology, average diameter, magnetic behavior and thermal decomposition analyses. The polymer nanospheres containing encapsulated magnetic nanoparticles showed superparamagnetic behavior and intensity average diameter about 150 nm. Immobilized cellulase exhibited broader temperature stability than in the free form and great reusability capacity, 69% of the initial enzyme activity was maintained after eight cycles of use. The magnetic support showed potential for cellulase immobilization and allowed fast and easy biocatalyst recovery through a single magnet.

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Cellulases are efficient enzymes for the conversion of cellulose into glucose. Their use in immobilized form enables them to be reused in successive cycles in many biotechnological processes. Unlike conventional methods of immobilization by covalent bonding, in miniemulsion polymerization the immobilization of enzyme and the synthesis of polymer nanoparticles (support) occur simultaneously. Based on these aspects, the immobilization of cellulose on poly(methyl methacrylate) (PMMA) nanoparticles by miniemulsion polymerization was studied. The surfactant type (non-ionic and ionic) and latex pH showed great influence on cellulase activity. High activity values were obtained only when non-ionic surfactant (Lutensol AT50) and buffering agent (NaHCO 3 ) were used simultaneously. MMA polymerization rate and final monomer conversion were not affected by the presence of cellulase. The maximum immobilization efficiency (60%) was obtained when 6 wt.% of cellulase was used and stable PMMA nanoparticles (133 nm) were obtained. The relative activity profile of immobilized cellulase, for pH as well as temperature, was similar to that reported for the free form. Immobilized enzyme keeps its activity throughout seven days when stored at 4 ºC and phosphate buffer pH 6.0. Based on the results obtained in this work, miniemulsion polymerization as a method for cellulase immobilization on PMMA nanoparticles showed to be a promising technique with high possibility of industrial application.

O objetivo deste estudo foi comparar a sensibilidade antifúngica e a presença dos genes de virulência SAP1-3 em linhagens de Candida spp. Foram estudados 49 isolados, sendo 30 C. albicans e 19 Candida não-albicans (CNA). A determinação do perfil de sensibilidade foi realizada conforme protocolo do Clinical and Laboratory Standards Institute. Para identificação dos genes SAP1-3, foi utilizado método de PCR. Todas as amostras de C. albicans foram sensíveis ao fluconazol, dentre as CNA 21% foram sensíveis e 68,4% foram SDD, 100% das linhagens de C. albicans e 94,7% de CNA foram sensíveis ao cetoconazol. Para itraconazol, 86,7% dos isolados de C. albicans e 42,1% de CNA foram sensíveis. Os genes mais frequentes nas linhagens de C. albicans foram SAP1 (56,6%,) e SAP2 (40%) seguido de SAP3 (26%). As amostras de CNA apresentaram um predomínio de SAP2 (42,1%), seguido por SAP1 (10,5%), SAP3 não foi identificado. As espécies de Candida apresentam diferenças significativas quanto ao perfil de sensibilidade a azólico e em relação à presença dos genes SAP1-3, sugerindo que esses fatores devem refletir em uma terapêutica e patogênese distintas para estas leveduras.