Background and Aims: Helicobacter pylori (H. pylori) eradication has become increasingly unsuccessful due to the prevalence of antibiotic resistance. To address this global issue, a novel strategy for eradication without antibiotics must be developed. The purpose of this study was to examine the effect of methylene blue (MB) with sodium bicarbonate (NaHCO3) on H. pylori using photodynamic antimicrobial chemotherapy. Materials and Methods: MB was basified using NaHCO3. The basic effect of MB with NaHCO3 was examined using an endoscope equipped with a laser light source. H. pylori was smeared on the culture media with basic MB, followed by illumination at approximately 1,100 lux for 10 and 20 seconds. After 4 days of culture, the basic effects were determined according to the bacterial growth. Results: The basic effects of MB appeared at a pH from 8.6 to 9.0 and at NaHCO3 concentrations between 2% and 6.5%. MB concentrations of > 0.05% exhibited the basic effects. The duration of irradiation had no remarkable effects. Conclusions: Our results showed that the laser endoscope and basic MB were effective for H. pylori eradication.
Background and aims: The prevalence of pathogenic Escherichia coli as well as E. coli O157 and antibiotic-resistant bacteria has increased. This study aimed to examine the effect of methylene blue (MB) with sodium bicarbonate (NaHCO3) against E. coli using photodynamic antimicrobial chemotherapy (PACT). Materials and methods: MB was basified using NaHCO3. E. coli and basic MB were smeared on the culture media followed by irradiation using a red light-emitting diode (LED) at 660 nm. Energy densities of 5, 10, 15, and 20 J/cm 2 were applied to the culture medium. After 24 h, the bactericidal effect of basic MB with LED irradiation was determined based on the bacterial growth.Results: The basic effect was observed with 1%-6% of NaHCO3 at 5 J/cm 2 . This effect increased between 1% and 2% of NaHCO3 at 10 J/cm 2 and 15 J/cm 2 , whereas decreased at the NaHCO3 concentrations of > 2%. Moreover, this effect decreased at an energy density of 20 J/cm 2 . The biphasic basic effect on bactericidal activity was observed between pH 8.6 -9.0. Conclusions: Thus, PACT using basic MB may be an effective method for pathogenic E. coli sterilization.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.