Restoration of the Antibiotic Susceptibility of Methicillin-Resistant Staphylococcus aureus and Extended-Spectrum ß-Lactamases Escherichia coli Through Combination with Chelerythrine.

ABSTRACT

Multidrug resistance poses a severe threat to public health and urgently requires new solutions. The natural product chelerythrine (CHE) is a benzophenanthridine alkaloid with antimicrobial potential. In this study, CHE was effective against seven gram-positive bacterial strains, and the minimum inhibitory concentrations (MICs) ranged from 2 to 4 µg/mL. By contrast, CHE showed inferior antibacterial activities against 11 gram-negative strains, and the MICs varied from 16 to 256 µg/mL. We also determined the synergistic/additive effects of combining CHE with nine currently used antibiotics. CHE restored the antibacterial efficacy of the antibiotics against methicillin-resistant Staphylococcus aureus and extended-spectrum ß-lactamases producing Escherichia coli. This study suggests that the combination of CHE with conventional antibiotics may be a promising strategy to combat infections caused by multidrug-resistant organisms.