Photo-inactivation ofNeisseria gonorrhoeae: A paradigm changing approach for combating antibiotic-resistant gonococcal infection

ABSTRACTNeisseria gonorrhoeaeis the causative pathogen of the sexually transmitted disease gonorrhea, a disease at risk of becoming untreatable due to increasing antibiotic resistance. There is a critical need for the development of new anti-gonococcal therapies. In this study, we investigated the effectiveness of antimicrobial blue light (aBL), an innovative non-antibiotic approach, for the inactivation of antibiotic-resistantN.gonorrhoeae. Our findings indicated that aBL at 405 nm preferentially inactivated antibiotic-resistantN. gonorrhoeaeover the vaginal epithelial cells. Furthermore, no genotoxicity of aBL to the vaginal epithelial cells was observed at the exposure for inactivatingN. gonorrhoeae. aBL also effectively inactivatedN. gonorrhoeaethat had invaded into the vaginal epithelial cells. No gonococcal resistance to aBL developed after 15 successive cycles of sub-therapeutic inactivation. Endogenous aBL-active photosensitizing chromophores (porphyrins and flavins) inN. gonorrhoeaewere identified and quantified using ultra performance liquid chromatography, with coproporphyrin being the most abundant endogenous porphyrin species. Taken together, aBL at 405 nm represents a potent potential treatment for gonococcal infections.One Sentence SummaryaBL selectively inactivated antibiotic-resistantNeisseria gonorrhoeaenover normal vaginal epithelial cells.