Antimicrobial Blue Light: An Alternative Therapeutic for Multidrug-Resistant Gonococcal Infections?

Gonorrhea is the second most prevalent sexually transmitted infection globally [1]. Despite the public health efforts to control gonorrhea for 70 years, these infections remain a significant public health concern. In 2015, a total of 395, 216 cases of gonorrhea were reported in the United States [2]. World widely, 106.1 million people are affected by gonococcal infections annually [3]. If gonococcal infections are not appropriately treated, they can result in severe complications and sequelae such as salpingitis and pelvic inflammatory disease, which may lead to sterility and/or ectopic pregnancy. In addition, epidemiologic and biologic studies have provided evidence that the failure to curb the transmission of gonorrhea facilitates the transmission of HIV infection [4]. Repeated infections are common and no state of protective immunity appears to develop as consequence of infection. Since there is no gonococcal vaccine, treatment of gonorrhea relies especially on antibiotics. However, Neisseria gonorrhoeae, the etiological agent of gonorrhea, is evolving into a superbug and may become untreatable due to its resistance to almost all the antibiotics previously and currently widely used (e.g., sulfonamides, penicillins, earlier cephalosporins, tetracyclines, macrolides, and fluoroquinolones) [5]. As such, the Centers for Disease Control and Prevention (CDC) has declared multidrug-resistant N. gonorrhoeae as an urgent threat [6,7]. There is consequently a critical need for the development of alternative therapeutics to combat gonococcal infections in high risk communities [8]. As the extensive use of antibiotics is the crucial factor leading to multidrug-resistance, non-antibiotic strategy is compelling [9].