Hydrogen Peroxide-Activated Nitric Oxide-Releasing Vancomycin-Loaded Electrostatic Complexation for Efficient Elimination of Methicillin-Resistant Staphylococcus aureus Abscesses.

The treatment of subcutaneous abscesses has been greatly hindered due to the spread of drug-resistant strains such as methicillin-resistant (MRSA). Thus, alternative strategies are highly desired to complement conventional antibiotic therapies and surgical intervention. As one of such strategies, applications of nitric oxide (NO) have shown great potential in the treatment of bacteria-induced subcutaneous abscesses by improving the efficacy of many therapeutic methods. However, it is extremely challenging to achieve precise delivery and controlled release because of its gaseous nature. In the present study, an effective strategy was reported in which on demand hydrogen peroxide (HO)-activated nitric oxide-releasing vancomycin (Van)-loaded electrostatic complexation (Lipo/Van@Arg) was fabricated. In this system, Van was encapsulated into a negative-charged DSPG/Chol liposome (Lipo/Van) and electrostatically bound with the positive-charged l-arginine (l-Arg). As expected, Lipo/Van@Arg exhibited superior bacterial binding and biofilm penetration abilities. After being in the interior of the biofilms, Lipo/Van@Arg could be triggered by the endogenous HO and effectively release NO. The released NO could exhibit combined antibacterial and biofilm eradication effects with Van. Moreover, an in vivo evaluation using a BALB/c mouse model of subcutaneous abscesses indicated that the combination treatment of NO and Van based on Lipo/Van@Arg could effectively eliminate MRSA from the abscesses, thereby preventing abscess recurrence. In summary, the Lipo/Van@Arg system developed in this study realized controlled delivery and precise release of NO, which had significant clinical implications in the efficient treatment of abscesses.