Candidiasis is a common infection primarily caused by the opportunistic fungus Candida albicans. Conventional antifungals have been associated with several limitations, and today, antimicrobial photodynamic therapy (aPDT) is raised as an adjuvant treatment. This study aimed to develop a carrier system for the photosensitizer methylene blue (MB) based on a gellan gum (GG) hydrogel, a nontoxic exopolysaccharide. Two formulations consisting of 0.6% and 1.0% (w/v) GG containing MB were prepared and characterized in relation to release kinetics, absorption spectroscopy, and optical shield formation. Then, the effects of MB GG formulations in aPDT using LED irradiation were evaluated against C. albicans. For this, aPDT was applied toC. albicans in planktonic and biofilm stages and also tested in a Galleria mellonella burn infection model. The successful incorporation of MB into the GG hydrogel was confirmed by absorption spectroscopy, with a characteristic peak at 660 nm for intact MB and both GG formulations. The GG0.6% hydrogel released 100% of MB in 12 min, whereas the GG1.0% hydrogel released only 75% of MB after 25 min. Furthermore, no optical shield formation was noticed with the MB gellan formulations in comparison to the aqueous form. In relation to antifungal activity on C. albicans, aPDT with GG0.6% and GG1.0% containing MB led to an eradication of planktonic cells and a partial reduction of biofilms, as observed in aPDT with MB aqueous. When aPDT was applied in G. mellonella larvae, an increase of 50% and 30% in survival rate was found, respectively, for the groups treated with MB gellan formulation and MB aqueous. In conclusion, the gellan gum formulations designed here were able to release MB and maintain its optical and photodynamic properties against C. albicans. In addition, aPDT with MB gellan formulations had higher in vivo efficacy than MB aqueous.
2 December 2023 in Brazilian Journal of Microbiology
The aim of this work is to evaluate the epidemiological profile of the cases of hepatitis B in the Metropolitan Region of Vale do Paraíba and the Northern Coast (RMVPLN), reported in the period from 2008 to 2018. The data of the 39 municipalities in the region were obtained using the Information System for Notificable Diseases of the Ministry of Health (SINAN) and analyzed using the programs Microsoft Office Excel 365 and Tabwin version 4.1.5. The variables employed were gender, age group, area of residence, schooling, skin color and mechanism of infection. In total, 1533 cases were reported, with a prevalence of cases in the male gender (58.51%; n=897), age group from 20 to 39 years old (44.03%; n=675), of self-declared white color (58.64%; n=899) and residing in the urban area (94.07%; n=1442), with the coastal municipalities corresponding to 43.24% (n=663) of the total of cases. The evaluation of schooling and mechanism of infection were impaired as a result of filling out the forms incompletely or with the field registration in the category 'ignored', reflecting a situation present in the notifications which can affect the quality of the data collected. This study is expected to assist in the visualization of the epidemiological characteristics of hepatitis B prevalent in RMVPLN, as well as help future works directed to this topic.