Understanding the mechanism of action of peptide (p-BthTX-I) derived from C-terminal region of phospholipase A2 (PLA)-like bothropstoxin-I on Gram-positive and Gram-negative bacteria.

Based on the antimicrobial activity of bothropstoxin-I (BthTX-I) and on the premise that a C-terminal peptide of Lys49 myotoxin can reproduce the antimicrobial activity of the parent protein, we aimed to study the mechanism of action of a peptide derived from the C-terminal region of the myotoxin BthTX-I [(p-BthTX-I), sequence: KKYRYHLKPFCKK, disulfide-linked dimer] against Gram-positive and Gram-negative bacteria. Fluorescence quenching technique showed that the carboxyfluorescein labeled-peptide [CF-(p-BthTX-I)] when incubated with E. coli displayed a superior penetration activity than when incubated with S.

Influence of light intensity and irradiation mode on methylene blue, chlorin-e6 and curcumin-mediated photodynamic therapy against Enterococcus faecalis.

This study aimed to evaluate the effect of the continuous irradiation with low intensity (continuous mode) and fractioned irradiation with high intensity (fractionated mode), keeping the same dose of light by using Light Emitting Diode (LEDs) with wavelength emission centered at 450 and at 660 nm, using methylene blue (MB), chlorin-e6 (Ce) and curcumin (CUR) as photosensitizers (PSs) against planktonic phase of E. faecalis. Cell viability was assessed by counting colonies forming per mL (CFU/mL), and the quantification of reactive species was performed by fluorescence with the photodegradation rate evaluated by measurements of absorbance of PSs at different times.

Phthalocyanine-loaded nanostructured lipid carriers functionalized with folic acid for photodynamic therapy.

Breast cancer is a serious public health problem that causes thousands of deaths annually. Chemotherapy continues to play a central role in the management of breast cancer but is associated with extreme off-target toxicity. Therefore, treatments that directly target the tumor and display reduced susceptibility to resistance could improve the outcome and quality of life for patients suffering from this disease.

Photodynamic and peptide-based strategy to inhibit Gram-positive bacterial biofilm formation.

The self-produced extracellular polymeric matrix of biofilms renders them difficult to eliminate once they are established. This makes the inhibition of biofilm formation key to successful treatment of biofilm infection. Antimicrobial photodynamic therapy (aPDT) and antimicrobial peptides offer a new approach as antibiofilm strategies.

Effective treatment and decolonization of a dog infected with carbapenemase (VIM-2)-producing Pseudomonas aeruginosa using probiotic and photodynamic therapies.

Background: Carbapenem-resistant bacterial infections are a critical problem in veterinary medicine with limited treatment options.

Objective: To describe effective probiotic and photodynamic therapy of a dog with gut colonization and ear infection caused by a hospital-associated lineage of carbapenemase (VIM-2)-producing Pseudomonas aeruginosa.

Animals: A 5-year-old Lhasa apso dog presented with otitis externa.

Molecular analyses of two bacterial sampling methods in ligature-induced periodontitis in rats.

The prevalence profile of periodontal pathogens in dental plaque can vary as a function of the detection method; however, the sampling technique may also play a role in determining dental plaque microbial profiles. We sought to determine the bacterial composition comparing two sampling methods, one well stablished and a new one proposed here. In this study, a ligature-induced periodontitis model was used in 30 rats.

Antimicrobial Photodynamic therapy enhanced by the peptide aurein 1.2.

In the past few years, the World Health Organization has been warning that the post-antibiotic era is an increasingly real threat. The rising and disseminated resistance to antibiotics made mandatory the search for new drugs and/or alternative therapies that are able to eliminate resistant microorganisms and impair the development of new forms of resistance. In this context, antimicrobial photodynamic therapy (aPDT) and helical cationic antimicrobial peptides (AMP) are highlighted for the treatment of localized infections.

Susceptibility of Enterococcus faecalis and Propionibacterium acnes to antimicrobial photodynamic therapy.

Bacterial resistance to available antibiotics nowadays is a global threat leading researchers around the world to study new treatment modalities for infections. Antimicrobial photodynamic therapy (aPDT) has been considered an effective and promising therapeutic alternative in this scenario. Briefly, this therapy is based on the activation of a non-toxic photosensitizing agent, known as photosensitizer (PS), by light at a specific wavelength generating cytotoxic singlet oxygen and free radicals.

Optimization of Antimicrobial Photodynamic Therapy in Biofilms by Inhibiting Efflux Pump.

Background: One of the main mechanisms of microbial resistance is given by efflux pumps, which reduce the effectiveness of antimicrobials by decreasing their intracellular concentration.

Objective And Methods: Considering that efflux pump inhibitors are promising adjuvant molecules for antibiotics in infections, in this study, using XTT test and colony forming unit (CFU) counting, we evaluated the association between the pump inhibitor verapamil (VP) and the antimicrobial photodynamic therapy (aPDT) mediated by methylene blue (MB) in biofilms of Escherichia coli and Staphylococcus aureus to optimize the bacterial reduction.

Results: By applying 44 J/cm, 215 μg/mL of VP, and 200 μg/mL of MB, we obtained 80% of metabolism reduction and 3.

Photodynamic therapy combined to cisplatin potentiates cell death responses of cervical cancer cells.

Background: Photodynamic therapy (PDT) has proven to be a promising alternative to current cancer treatments, especially if combined with conventional approaches. The technique is based on the administration of a non-toxic photosensitizing agent to the patient with subsequent localized exposure to a light source of a specific wavelength, resulting in a cytotoxic response to oxidative damage. The present study intended to evaluate in vitro the type of induced death and the genotoxic and mutagenic effects of PDT alone and associated with cisplatin.

Polymeric Nanoparticle-Based Photodynamic Therapy for Chronic Periodontitis in Vivo.

Antimicrobial photodynamic therapy (aPDT) is increasingly being explored for treatment of periodontitis. Here, we investigated the effect of aPDT on human dental plaque bacteria in suspensions and biofilms in vitro using methylene blue (MB)-loaded poly(lactic-co-glycolic) (PLGA) nanoparticles (MB-NP) and red light at 660 nm. The effect of MB-NP-based aPDT was also evaluated in a clinical pilot study with 10 adult human subjects with chronic periodontitis.

Nanotechnology-Based Drug Delivery Systems for Photodynamic Therapy of Cancer: A Review.

Photodynamic therapy (PDT) is a promising alternative approach for improved cancer treatment. In PDT, a photosensitizer (PS) is administered that can be activated by light of a specific wavelength, which causes selective damage to the tumor and its surrounding vasculature. The success of PDT is limited by the difficulty in administering photosensitizers (PSs) with low water solubility, which compromises the clinical use of several molecules.

Synergistic antimicrobial effect of photodynamic therapy and ciprofloxacin.

The occurrence of a variety of pathogens resistant to current antibiotics remains the major problem in medical care, especially when bacterial infections are established as biofilms. In this study, we propose the use of photodynamic therapy (PDT) as a monotherapy and associated with antibiotic as an alternative treatment. The aim of this study was to analyze the effects of PDT mediated by methylene blue (MB) on Staphylococcus aureus (ATCC 25923) and Escherichia coli (ATCC 25922) in both biofilm and planktonic phases.

Synergistic effect of photodynamic therapy and cisplatin: a novel approach for cervical cancer.

Cervical cancer is a neoplasia primarily caused by Human papillomavirus (HPV) infection. Current treatment modalities involve cisplatin, a potent chemotherapeutic agent with severe adverse effects. Photodynamic therapy (PDT) is a promising modality for the treatment of cancer and infections, which has been associated with innovative therapeutic approaches, especially for the treatment of neoplasias.