Attaching the NorA Efflux Pump Inhibitor INF55 to Methylene Blue Enhances Antimicrobial Photodynamic Inactivation of Methicillin-Resistant Staphylococcus aureus in Vitro and in Vivo

作者：Rineh Ardeshir; Dolla Naveen K; Ball Anthony R; Magana Maria; Bremner John B; Hamblin Michael R; Tegos George P^*; Kelso Michael J^*

来源：ACS Infectious Diseases, 2017, 3(10): 756-766.

DOI：10.1021/acsinfecdis.7b00095

• antimicrobial photodynamic inactivation
• photosensitizer-efflux pump inhibitor hybrid
• methicilllin resistant Staphylococcus aureus
• reactive oxygen species
• bioluminescence wound infection model

Antimicrobial photodynamic inactivation (aPDI) uses photosensitizers (PSs) and harmless visible light to generate reactive oxygen species (ROS) and kill microbes. Multidrug efflux systems can moderate the phototoxic effects of PSs by expelling the compounds from cells. We hypothesized that increasing intracellular concentrations of PSs by inhibiting efflux with a covalently attached efflux pump inhibitor (EPI) would enhance bacterial cell phototoxicity and reduce exposure of neighboring host cells to damaging ROS. In this study, we tested the hypothesis by linking NorA EPIs to methylene blue (MB) and examining the photoantimicrobial activity of the EPI MB hybrids against the human pathogen methicillin-resistant Staphylococcus aureus (MRSA). Photochemical/photophysical and in vitro microbiological evaluation of 16 hybrids carrying four different NorA EPIs attached to MB via four linker types identified INF55-(Ac)en MB 12 as a lead. Compound 12 showed increased uptake into S. aureus cells and enhanced aPDI activity and wound healing effects (relative to MB) in a murine model of an abrasion wound infected by MRSA. The study supports a new approach for treating localized multidrug-resistant MRSA infections and paves the way for wider exploration of the EPI PS hybrid strategy in aPDI.

• 出版日期2017-10