Antagonism between Resveratrol and antimicrobial agents

GASPAR TOSATO, MAIRA; SCHILARDI, PATRICIA; FERNANDEZ LORENZO DE MELE, M; THOMAS, ANDRÉS H.; MIÑAN, A; LORENTE, CAROLINA

Carlos Paz

Encuentro; XIII Encuentro Latinoamericano de Fotoquímica y Fotobiología; 2017

Several antimicrobial agents, such as antibiotics and sensitizers used in photodynamic therapy, are efficient to generate reactive oxygen species (ROS) in order to eliminate undesired pathogenic microorganisms that are harmful to health.Among natural antioxidants reverastrol (RSV) is efficient to prevent damage from ROS. However, the consequences of the administration of RSV during an antimicrobial treatment are unknown. To investigate possible antagonistic or synergistic effects of RSV during antibiotic therapy (levofloxacin, LVX) or a photodynamic inactivation (PDI) therapy (visible radiation and methylene blue, MB), the elimination of Staphyloccocus aureus of a planktonic culture was evaluated in the presence of RSV. Results shows that the antimicrobial capacity of these therapies is significantly diminished when LVX or MB are co-administered with RSV. In the case of LVX, the presence of RSV increases 20-fold the bacterial survival compared with LVX (0.125 g/ml) alone. Moreover coadministration of both MB and RSV decrease MB efficacy, which improve bacteria survival from 10 to 1000-fold in the whole range of MB concentration tested (6.25 to 50 g/ml). The results presented in this work indicate that the consumption of RSV during an antimicrobial treatment is strongly discouraged. Finally, considering that the microbiocidal activity of host defenses (neutrophils, macrophages) is also mediated by ROS, the topical addition of RSV, may also affect the normal control of pathogens of the human body. Therefore this work highlight the importance of the evaluation of possible antagonistic effect when an antimicrobial agent with ROS-mediated action is co-administrated with RSV.