Navegando por Assunto "Galleria mellonella"

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    Antimicrobial Photodynamic Therapy Mediated by Fotenticine and Methylene Blue on Planktonic Growth, Biofilms, and Burn Infections of Acinetobacter baumannii
    (MDPI) Figueiredo-Godoi, Lívia Mara Alves; Garcia, Maíra Terra; Pinto, Juliana Guerra; Ferreira-Strixino, Juliana; Faustino, Eliseu Gabriel; Pedroso, Lara Luise Castro; Junqueira, Juliana Campos
    Antimicrobial photodynamic therapy (aPDT) is considered a promising alternative strategy to control Acinetobacter baumannii infections. In this study, we evaluated the action of aPDT mediated by a new photosensitizer derivative from chlorin e-6 (Fotoenticine—FTC) on A. baumannii, comparing its effects with methylene blue (MB). For this, aPDT was applied on A. baumannii in planktonic growth, biofilms, and burn infections in Galleria mellonella. The absorption of FTC and MB by bacterial cells was also evaluated using microscopic and spectrophotometric analysis. The results of planktonic cultures showed that aPDT reduced the number of viable cells compared to the non-treated group for the reference and multidrug-resistant A. baumannii strains. These reductions varied from 1.4 to 2 log10 CFU for FTC and from 2 log10 CFU to total inhibition for MB. In biofilms, aPDT with MB reduced 3.9 log10 CFU of A. baumannii, whereas FTC had no effect on the cell counts. In G. mellonella, only MB-mediated aPDT had antimicrobial activity on burn injuries, increasing the larvae survival by 35%. Both photosensitizers were internalized by bacterial cells, but MB showed a higher absorption compared to FTC. In conclusion, MB had greater efficacy than FTC as a photosensitizer in aPDT against A. baumannii.
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    Effects of antimicrobial photodynamic therapy with photodithazine® on methicillin-resistant Staphylococcus aureus (MRSA): Studies in biofilms and experimental model with Galleria mellonella
    (Elsevier) Souza, Beatriz Müller Nunes; Miñán, Alejandro Guillermo; Brambilla, Isabelle Ribeiro; Pinto, Juliana Guerra; Garcia, Maíra Terra; Junqueira, Juliana Campos; Ferreira-Strixino, Juliana
    Staphylococcus aureus infections are a severe health problem due to the high mortality rate. Conventional treatment of these infections is via the administration of antibiotics. However, its indiscriminate use can select resistant microorganisms. Thus, it is necessary to develop alternatives for antibiotic therapy. Antimicrobial Photodynamic Therapy (aPDT), a therapeutic method that associates a photosensitizer (PS), a light source with adequate wavelength to the PS, interacts with molecular oxygen generating reactive oxygen species responsible for cell inactivation, is a viable alternative. This work aimed to analyze, in vitro and in vivo, the action of aPDT with PS Photodithazine® (PDZ) on the methicillin-resistant S. aureus (MRSA) strain. In the in vitro method, the S. aureus biofilm was incubated with PDZ at 50 and 75 μg.mL−1 for 15 min, adopting the light dose of 25, 50, and 100 J/cm2. In addition, PS interaction, formation of reactive oxygen species (ROS), bacterial metabolism, adhesion, bacterial viability, and biofilm structure were evaluated by scanning electron microscopy. Subsequently, the strain was inoculated into models of Galleria mellonella, and the survival curve, health scale, blood cell analysis, and CFU/mL of S. aureus in the hemolymph were analyzed after aPDT. In the in vitro results, bacterial reduction was observed in the different PDZ concentrations, highlighting the parameters of 75 μg.mL−1 of PDZ and 100 J/cm2. As for in vivo results, aPDT increased survival and stimulated the immune system of G. mellonella infected by S. aureus. aPDT proved effective in both models, demonstrating its potential as an alternative therapy in treating MRSA bacterial infections.