A new acridine-based photosensitizer with ultra-low light requirement efficiently inactivates carbapenem-resistant Acinetobacter baumannii and methicillin-resistant Staphylococcus aureus and degrades their antibiotic resistance genes

The spread of antibiotic resistant pathogens and antibiotic resistance genes (ARGs) in the environment poses a serious threat to public health. However, existing methods are difficult to effectively remove antibiotic resistant pathogens and ARGs from the environment. In this study, we synthesized a new acridine-based photosensitizer, 2,7-dibromo-9-mesityl-10-methylacridinium perchlorate (YM-3), by the heavy atom effect, which could photo -dynamically inactivate antibiotic resistant pathogens and reduce ARGs by generating singlet oxygen (1O2) in an aqueous environment. The 1O2 yield of YM-3 was 4.9 times that of its modified precursor. YM-3 could reduce the culturable number and even the viable counts of methicillin-resistant Staphylococcus aureus and carbapenem-resistant Acinetobacter baumannii to 0 (inactivation rate > 99.99999%) after 2 and 8 h of low-intensity blue light (15 W/m2) irradiation, respectively. After 20 h of light exposure, the copy numbers of ARGs in both bacteria were reduced by 5.80 and 4.48 log, respectively, which might indicate that ARGs had been degraded. In addition, YM-3 still had an efficient bactericidal effect after five inactivation cycle. These characteristics of ultra-low light intensity requirement and efficient bactericidal ability make YM-3 have good application prospects for disin-fection in indoor and sunlight environment.

Automated summary

The spread of antibiotic resistant pathogens and antibiotic resistance genes in the environment is a serious threat to public health. Existing methods are ineffective in removing them, but a new acridine-based photosensitizer called YM-3 has been developed in this study, which can effectively inactivate antibiotic resistant pathogens and reduce antibiotic resistance genes by generating singlet oxygen. YM-3 has shown a high inactivation rate for methicillin-resistant Staphylococcus aureus and carbapenem-resistant Acinetobacter baumannii, and it can effectively reduce the copy numbers of antibiotic resistance genes in these bacteria. It also has a long-lasting bactericidal effect, making it suitable for disinfection in various environments.