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1.
J Microbiol Biotechnol ; 31(9): 1200-1209, 2021 Sep 28.
Artigo em Inglês | MEDLINE | ID: mdl-34319262

RESUMO

Sepsis is an acute inflammatory response that leads to life-threatening complications if not quickly and adequately treated. Cytolysin, hemolysin, and pneumolysin are toxins produced by gram-positive bacteria and are responsible for resistance to antimicrobial drugs, cause virulence and lead to sepsis. This work assessed the effects of aloe-emodin (AE) and photodynamic therapy (PDT) on sepsis-associated gram-positive bacterial toxins. Standard and antibiotic-resistant Enterococcus faecalis, Staphylococcus aureus, and Streptococcus pneumonia bacterial strains were cultured in the dark with varying AE concentrations and later irradiated with 72 J/cm-2 light. Colony and biofilm formation was determined. CCK-8, Griess reagent reaction, and ELISA assays were done on bacteria-infected RAW264.7 cells to determine the cell viability, NO, and IL-1ß and IL-6 pro-inflammatory cytokines responses, respectively. Hemolysis and western blot assays were done to determine the effect of treatment on hemolysis activity and sepsis-associated toxins expressions. AE-mediated PDT reduced bacterial survival in a dose-dependent manner with 32 µg/ml of AE almost eliminating their survival. Cell proliferation, NO, IL-1ß, and IL-6 cytokines production were also significantly downregulated. Further, the hemolytic activities and expressions of cytolysin, hemolysin, and pneumolysin were significantly reduced following AE-mediated PDT. In conclusion, combined use of AE and light (435 ± 10 nm) inactivates MRSA, S. aureus (ATCC 29213), S. pneumoniae (ATCC 49619), MDR-S. pneumoniae, E. faecalis (ATCC 29212), and VRE (ATCC 51299) in an AE-dose dependent manner. AE and light are also effective in reducing biofilm formations, suppressing pro-inflammatory cytokines, hemolytic activities, and inhibiting the expressions of toxins that cause sepsis.


Assuntos
Antraquinonas/farmacologia , Toxinas Bacterianas/metabolismo , Bactérias Gram-Positivas/efeitos dos fármacos , Fotoquimioterapia , Sepse/microbiologia , Animais , Biofilmes/efeitos dos fármacos , Biofilmes/crescimento & desenvolvimento , Sobrevivência Celular/efeitos dos fármacos , Citocinas/metabolismo , Relação Dose-Resposta a Droga , Farmacorresistência Bacteriana/efeitos dos fármacos , Bactérias Gram-Positivas/metabolismo , Bactérias Gram-Positivas/patogenicidade , Camundongos , Viabilidade Microbiana/efeitos dos fármacos , Células RAW 264.7 , Virulência/efeitos dos fármacos
2.
Photobiomodul Photomed Laser Surg ; 38(1): 36-42, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31634029

RESUMO

Background: The search for alternative therapeutics against antibiotic-resistant bacteria is highly desirable. A promising approach is photodynamic antimicrobial chemotherapy. Objective: This work evaluated the photodynamic inactivation (PDI) efficacy of hypocrellin B (HB) on Gram-positive antibiotic-resistant bacteria. Methods: PDI efficacy of HB on Gram-positive standard and antibiotic-resistant Staphylococcus aureus, Enterococcus faecalis, and Streptococcus pneumonia and Gram-negative Escherichia coli and Klebsiella pneumoniae was assessed. HB photoactivity on biofilms formed by the Gram-positive bacteria and its cytotoxicity on mammalian CT26 cells were also investigated. Results: HB showed no obvious dark toxicity, but provided concentration-dependent inactivation of bacteria and mammalian cells. After irradiation with 72 J/cm2 light, 100 µM of HB achieved about 7 log10 reductions in bacterial survival of Gram-positive strains, but yielded only 2 log10 reductions in bacterial survival of Gram-negative strains. Gram-positive bacteria were as susceptible to PDI in biofilms as in planktonic suspensions, but the efficacy was attenuated. Conclusions: The results suggested that HB could serve as a potential antibacterial photosensitizer against Gram-positive antibiotic-resistant bacteria.


Assuntos
Bactérias Gram-Positivas/efeitos da radiação , Infecções por Bactérias Gram-Positivas/tratamento farmacológico , Perileno/análogos & derivados , Fotoquimioterapia/métodos , Quinonas/farmacologia , Biofilmes/efeitos dos fármacos , Biofilmes/efeitos da radiação , Farmacorresistência Bacteriana , Perileno/química , Perileno/farmacologia , Quinonas/química , Xenônio
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