DANIELA DE FATIMA TEIXEIRA DA SILVA
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Resumo IPEN-doc 30132 Photodynamic inactivation against the critical priority pathogen Candida auris2023 - SILVA, ABDENEGO R.; CABRAL, FERNANDA V.; SILVA, CAMILA R.; SILVA, DANIELA F.T.; FREITAS, ANDERSON Z.; FONTES, ADRIANA; RIBEIRO, MARTHA S.Fungal pathogens and their associated infections present a growing challenge to global public health. Among these pathogens, Candida auris has emerged as a highly hazardous hospital-acquired microorganism, included in the critical priority group by the World Health Organization. Methylene Blue (MB) is a widely acknowledged photosensitizer utilized in antifungal photodynamic inactivation (PDI) and holds significant clinical applications. The MB methylation results in the formation of a more lipophilic compound, the 1,9-dimethyl MB (DMMB), which can have an enhanced interaction with cell membranes. Nevertheless, PDI mediated by DMMB to combat fungi remains little explored. In this study, we assessed the impact and underlying mechanisms of PDI using MB (MB-PDI) or DMMB (DMMB-PDI) combined with a red LED against C. auris. PDI was conducted on the CBS 10913 strain of C. auris, utilizing different concentrations of MB (0 – 100 μM) or DMMB (0 – 3 μM) at light doses of 10 or 30 J/cm². To evaluate the PDI efficacy, we measured colony-forming units and monitored reactive oxygen species (ROS) production. Additionally, we assessed lipid peroxidation (LPO) and mitochondrial membrane potential (ΔΨm) to gain insights into the differences between MB and DMMB. Our findings revealed that DMMB-PDI successfully eradicated C. auris yeasts at 3 μM concentration, irrespective of the light dose, whereas MB (100 μM) only exhibited cell eradication at the highest light dose. ROS formation was more pronounced for DMMB than MB at 10 J/cm2. At 30 J/cm2, MB and DMMB produced similar ROS levels. In sublethal conditions, DMMB-PDI induced significantly higher LPO, and ΔΨm levels compared to MB-PDI. Furthermore, DMMB-PDI effectively inhibited biofilm formation and disrupted mature biofilms, with no observed toxicity in fibroblast cells. In conclusion, our study demonstrates the potential of DMMB-PDI as a promising weapon to combat the global priority pathogen C. auris. The enhanced PDI efficacy and biofilm eradication capacity of DMMB make it a valuable candidate for further exploration in the fight against this hazardous pathogen. As the incidence of drug-resistant fungal infections continues to rise, the development of innovative and effective therapeutic strategies like DMMB-PDI is crucial in safeguarding public health worldwide.Artigo IPEN-doc 29884 New insights in phenothiazinium-mediated photodynamic inactivation of candida auris2023 - SILVA, ABDENEGO R.; CABRAL, FERNANDA V.; SILVA, CAMILA R.; SILVA, DANIELA F.T.; FREITAS, ANDERSON Z.; FONTES, ADRIANA; RIBEIRO, MARTHA S.n recent years, Candida auris has emerged as a hazardous hospital-acquired pathogen. Its resistance to antifungal treatments makes it challenging, requiring new approaches to manage it effectively. Herein, we aimed to assess the impact of photodynamic inactivation mediated by methylene blue (MB-PDI) or 1,9-dimethyl MB (DMMB-PDI) combined with a red LED against C. auris. To evaluate the photoinactivation of yeasts, we quantified colony-forming units and monitored ROS production. To gain some insights into the differences between MB and DMMB, we assessed lipid peroxidation (LPO) and mitochondrial membrane potential (ΔΨm). After, we verified the effectiveness of DMMB against biofilms by measuring metabolic activity and biomass, and the structures were analyzed through scanning electron microscopy and optical coherence tomography. We also evaluated the cytotoxicity in mammalian cells. DMMB-PDI successfully eradicated C. auris yeasts at 3 μM regardless of the light dose. In contrast, MB (100 μM) killed cells only when exposed to the highest dose of light. DMMB-PDI promoted higher ROS, LPO and ΔΨm levels than those of MB. Furthermore, DMMB-PDI was able to inhibit biofilm formation and destroy mature biofilms, with no observed toxicity in fibroblasts. We conclude that DMMB-PDI holds great potential to combat the global threat posed by C. auris. © 2023 by the authors.Artigo IPEN-doc 29710 Photodynamic therapy mediated by a red LED and methylene blue inactivates resistant leishmania amazonensis2023 - CABRAL, FERNANDA V.; YOSHIMURA, TANIA M.; SILVA, DANIELA de F.T. da; CORTEZ, MAURO; RIBEIRO, MARTHA S.Cutaneous leishmaniasis is a neglected parasitic disease that leads to destructive lesions. The emergence of drug resistance has been a global concern over the past years. Photodynamic therapy (PDT) mediated by a red LED and methylene blue (MB) involves the overproduction of oxidative stress, which oxidizes several cellular biomolecules and prevents the selection of resistant strains. Herein, we investigated the potential of PDT mediated by MB against wild-type and miltefosine-resistant strains of Leishmania amazonensis. As a result, both strains were susceptible to PDT, thus encouraging us to seek the best conditions to overcome the drug resistance problem in cutaneous leishmaniasis.