Controle microbiano por fotoinativação em cepas bacterianas resistentes isoladas em trechos do rio Camarajipe

Abstract

Introduction: Camarajipe River belongs to one of the most polluted watersheds in Salvador, having been degraded due to the lack of sanitation and the illegal discharge of contaminated effluents. These metropolitan rivers are often populated by multidrug-resistant microorganisms. Microbial resistance is a growing concern for public health, especially in densely populated urban areas where antibiotic contamination can promote the emergence of multidrug-resistant strains. This dissertation explores photoinactivation, an alternative technique for microbial control that uses light and a photosensitizing molecule as a possible solution to combat these strains without promoting additional resistance. Objective: The main objective of the study was to investigate the effectiveness of photoinactivation against resistant bacterial strains isolated from the Camarajipe River. Additionally, the study explored the potential synergy between photoinactivation and the use of high-frequency equipment to amplify antimicrobial effects. Methods: This study involved the collection of water samples from different points along the Camarajipe River to isolate multidrug-resistant Pseudomonas spp. strains. After identifying the strains, photoinactivation experiments were conducted using Methylene Blue as a photosensitizer and a red LED light device. High-frequency current experiments were also conducted to evaluate its bactericidal capacity, both in isolation and in combination with photoinactivation. Results: Photoinactivation proved to be effective against multidrug-resistant strains, with significant inhibition observed in bacterial cultures when an appropriate concentration of Methylene Blue was used. The application of high-frequency currents also demonstrated bactericidal efficacy but only when applied before the addition of the photosensitizer, when the therapy was conducted in liquid media, showing significant effect alone when done in solid media. The combination of the two techniques showed promising results, suggesting that the use of high-frequency currents can enhance the effects of photoinactivation. This study highlights the relevance of alternative methods, such as photoinactivation combined with high frequency, in combating infections caused by resistant strains, offering a potential pathway to reduce the dependence on antibiotics in the treatment of bacterial infections.