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Multidrug-resistant microorganisms have become a significant public health threat, and traditional antibiotics are becoming ineffective. Photodynamic therapy (PDT) is a promising alternative that utilizes photosensitizers and light to produce Reactive Oxygen Species (ROS) that can kill microorganisms. Zinc phthalocyanine (ZnPc) is a promising photosensitizer due to its strong affinity for encapsulation in nanoemulsions and its antimicrobial properties. In this study, nanoemulsion was prepared using Miglyol 812N, a surfactant, and distilled water to dissolve hydrophobic drugs such as ZnPc. The nanoemulsion was characterized by its particle size, polydispersity index, Transmission Electron Microscope and Zeta potential, and the results showed that it was an efficient nanocarrier system that facilitated the solubilization of hydrophobic drugs in water. The use of ZnPc encapsulated in the nanoemulsion produced through the spontaneous emulsification method resulted in a significant reduction in cell survival percentages of gram-positive Staphylococcus aureus and gram-negative Escherichia coli by 85% and 75%, respectively. This may be attributed to the more complex cell membrane structure of E. coli compared to S. aureus. This demonstrates the potential of nanoemulsion-based PDT as an effective alternative to traditional antibiotics for treating multidrug-resistant microorganisms. [ABSTRACT FROM AUTHOR]

Background: Biofilms affect >80% bacterial infections in human and are usually difficult to eradicate because of their inherent drug resistance.Methods: We investigated the effectiveness of antimicrobial blue light (aBL) (wavelength, 415 nm) for inactivating Acinetobacter baumannii or Pseudomonas aeruginosa biofilms in 96-well microplates or infected mouse burn wounds.Results: In vitro, in 96-well microplates, exposure of 24-hour-old and 72-hour-old A. baumannii biofilms to 432 J/cm(2) aBL resulted in inactivation of 3.59 log10 and 3.18 log10 colony-forming units (CFU), respectively. For P. aeruginosa biofilms, similar levels of inactivation-3.02 log10 and 3.12 log10 CFU, respectively-were achieved. In mouse burn wounds infected with 5 × 10(6) CFU ofA. baumannii, approximately 360 J/cm(2) and 540 J/cm(2) aBL was required to inactivate 3 log10 CFU in biofilms when delivered 24 and 48 hours, respectively, after bacterial inoculation. High-performance liquid chromatography analysis revealed the presence of endogenous porphyrins in both A. baumannii and P. aeruginosa TUNEL assay detected no apoptotic cells in aBL-irradiated mouse skin at up to 24 hours after aBL exposure (540 J/cm(2)).Conclusions: aBL has antimicrobial activity in biofilms ofA. baumannii and P. aeruginosa and is a potential therapeutic approach for biofilm-related infections. [ABSTRACT FROM AUTHOR]

The conventional methods for microbial viability quantification require cultivation and are laborious. There is consequently a widespread need for cultivation-free methods. The adenosine triphosphate (ATP) bioluminescence-sensing assay is considered an extremely effective biosensor; hence ATP is the energy currency of all living microbes and can be used as a rapid indicator of microbial viability. We developed an ATP bioluminescence-sensing assay to detect microbial viability. A bioluminescent recombinant E. coli strain was used with luciferase extracted from transformed bacteria. Results showed that there is a direct correlation between the bioluminescence intensity of the ATP bioluminescence-sensing assay and the microbial viability. Bacterial counts from food samples were detected using the developed sensing assay and validated by the traditional plate-counting method. Compared with the plate-counting method, ATP bioluminescence-sensing assay is a more rapid and efficient approach for detecting microbial viability. [ABSTRACT FROM AUTHOR]