Affiliation:
1. Department of Pharmacology and Toxicology, College of Veterinary Medicine, Henan Agricultural University
Abstract
Discovering new strategies to combat the multi-drug resistance bacteria constitutes a major medical challenge of our time. Previously, artesunate (AS) has been reported to exert antibacterial enhancement activity in combination with β-lactam antibiotics, via inhibition of the efflux pump AcrB. However, combination of AS and colistin (COL) revealed weak synergistic effect against a limited number of strains, and few studies have further explored its possible mechanism of synergistic action. In this paper, we found that AS and EDTA could strikingly enhance the antibacterial effects of COL against
mcr
-
1
−
and
mcr
-
1
+
Salmonella
strains either
in vitro
or
in vivo
, when used in triple combination. The excellent bacteriostatic effect was primarily related to the increased cell membrane damage, accumulation of toxic compounds and inhibition of MCR-1. The potential binding sites of AS to MCR-1 (THR283, SER284, and TYR287) were critical for its inhibition of MCR-1 activity. Additionally, we also demonstrated that the CheA of chemosensory system and virulence-related protein SpvD were critical for the bacteriostatic synergistic effects of the triple combination. Selectively targeting CheA, SpvD or MCR using the natural compound artesunate could be further investigated as an attractive strategy for treatment of
Salmonella
infection. Collectively, our work opens up avenues towards the potentiation of colistin and revealed an alternative drug combination strategy to overcome COL resistant bacterial infections.
Publisher
eLife Sciences Publications, Ltd