The rise of antibiotic-resistant infectious diseases is becoming an alarming problem for public health to the difficulty of treatment, resulting in a high number of deaths annually. Photodynamic inactivation (PDI) has shown promise as an effective method, which is based on the use of a photosensitize, when activated by light, generates reactive oxygen species (ROS), causing damage to the metabolic and structures of target cells, resulting in their death. This study aims to analyze the action of curcumin acting as a photosensitizer and the effect on the susceptibility of different antibiotics to Staphylococcus aureus resistant to methicillin (MRSA). The experimental groups and the analyzes were established from the central composite planning (10 µM, 10 J/cm²). The results demonstrated that PDI reduces the concentration of antibiotics needed to act against MRSA compared to the results of the control group. Combining both treatments enhances the action against target cells, enabling successful results.
The objective of this study was to prepare mixed cultures of both sensitive and resistant bacteria of the same species in varying proportions (20% and 80%, 50% and 50% and 80% and 20%) We aimed to analyze the minimum inhibitory concentration (MIC) both before and after photoinactivation treatment. This treatment involved the use of the synthetic photosensitizer curcumin 5 mM (PDTPharma®) and irradiation with an LED lighting device (Biotable® - produced by MM Optics-Brasil) emitting a wavelength of 450 nm, at 40 mW/cm², and a light dose of 10 J/cm². The purpose was to examine the impact of photodynamic action on the spread of bacterial resistance. Combating the proliferation of antimicrobial resistance is a critical global health issue, necessitating treatment methods that adequately address this challenge.
The rise of antimicrobial-resistant microorganisms prompts the exploration of strategies to rejuvenate traditional antibiotics. Photodynamic Inactivation (PDI) offers an alternative by combining a photosensitizer (PS) with light, generating reactive oxygen species that efficiently eliminate undesirable cells. In this study, curcumin and 450nm light are applied, resulting in reduced minimum inhibitory concentrations (MIC) for antibiotics. The application of PDI proves effective in diminishing the necessary antibiotic dosage for bacterial cell elimination, especially against resistant strains. Additionally, the interaction between the photosensitizer and antibiotics induces notable alterations in bacterial metabolism and biomolecules. These findings are crucial for advancing from in vitro studies to the clinical implementation of PDI as a promising adjunct to antibiotic therapy, offering potential solutions in the battle against antimicrobial resistance.
Antibiotic is one of the most important medical inventions in the 20th century 1. However, bacterial resistance to antibiotics is becoming a global health-care problem 2. One of the important measures to tackle this problem is fast detection bacterial antibiotic susceptibility 1. In this research topic and inspired by the work report of Soares et. al. 3,4 we were motivated to developed this study to identification of resistance to antibiotic in Staphylococcus aureus. By mean of machine learning implementation in data analyses of Fourier-Transform Infrared Spectroscopy (FTIR) spectra, we found promisor results in samples with and without antibiotic resistance develop.
Antimicrobial photodynamic therapy (aPDT) in combination with antibiotics leads to a notable reduction in antibiotic minimum inhibitory concentration (MIC). Four antibiotic resistant bacterial strains (E. faecalis OG1RF(+), P. aeruginosa PA01, K. pneumoniae, E. coli ETEC) were evaluated with four antibiotics (ampicillin, kanamycin, tetracycline, chloramphenicol) in a combination treatment with methylene blue aPDT. Treatment involved co-culture of antibiotics with 1.0 μ𝑀 MB followed by exposure to 0 to 14.4 𝐽𝑐𝑚2 of light over 0 to 10 minutes at a rate of 30 𝑚𝑊𝑐𝑚2. MIC of test groups was compared to controls to evaluate direct effects on resistance, and further aPDT controls were used to evaluate measures of synergistic effect based on fractional inhibitory concentration index (FICI). It was found that 12 of 16 strain-antibiotic combinations have a reduction in antibiotic resistance during treatment, two of which are statistically significant. The calculated FICI values for these combinations contain 6 indifferent values between 1.0 and 1.5 and 10 additive values at or below 1.0, one of which was 0.43, qualifying as synergistic treatment. Overall, this survey provides a brief exploration of aPDT as an adjunct therapy for combatting antibiotic resistant bacteria. Further targeted research on strain-antibiotic combinations of interest may reveal valuable synergistic effects.
Antimicrobial Photodynamic Therapy (APDT) is being increasingly used for treatment of acute infections. The cause of upper respiratory tract infections represent a large part of the diseases caused by drug-resistant microorganisms. Acute pharyngotonsillitis caused by bacteria represent many cases that are admitted to hospital emergency dialy. Antibiotics are the first line treatment for bacterial pharyngotonsillitis. However, drug failure may occur by antibiotic therapy, which can cause recurrent pharyngonsilitis. Pharyngotonsillitis treatment has been studied by CEPOF for the last five years. The studies were focused on the following tests: determination of a formulation used in tonsils; development of lighting device for tonsils; incorporation of the photosensitizer by the main pathogenic microorganisms, microbial behavior in successive PDT sessions; study of microbial virulence of surviving bacteria after PDT sessions; development of clinical study phase I and II. The results have shown that under specified the PDT can be used for the treatment of pharyngotonsillitis. It was possible to observe the increase of incorporation of photosensitizer depending of formulation composition; the microbial resistance behavior in relation to successive PDT sessions; the safety of the technique in clinical phase I study, and clinical results, not yet completed, in phase II showed the PDT efficient against different types of pathogenic microorganisms in adults.
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