Polydatin prevent lung epithelial cell from Carbapenem-resistant Klebsiella pneumoniae injury by inhibiting biofilm formation and oxidative stress.

Carbapenem-resistant Klebsiella pneumoniae (CRKP) causes severe inflammation in various infectious diseases, such as bloodstream infections, respiratory and urinary tract infections, which leads to high mortality. Polydatin (PD), an active ingredient of Yinhuapinggan granule, has attracted worldwide attention for its powerful antioxidant, anti-inflammatory, antitumor, and antibacterial capacity. However, very little is known about the effect of PD on CRKP. In this research, we evaluated the inhibitory effects of PD on both the bacterial level and the bacterial-cell co-culture level on anti-biofilm and efflux pumps and the other was the inhibitory effect on apoptosis, reactive oxygen species (ROS), mitochondrial membrane potential (MMP) after CRKP induction. Additionally, we validated the mechanism of action by qRT-PCR and western blot in human lung epithelial cells. Firstly, PD was observed to have an inhibitory effect on the biofilm of CRKP and the efflux pump AcrAB-TolC. Mechanically, CRKP not only inhibited the activation of Nuclear Factor erythroid 2-Related Factor 2 (Nrf-2) but also increased the level of ROS in cells. These results showed that PD could inhibit ROS and activate Nrf-2 production. Together, our research demonstrated that PD inhibited bacterial biofilm formation and efflux pump AcrAB-TolC expression and inhibited CRKP-induced cell damage by regulating ROS and Nrf-2-regulated antioxidant pathways.