Inosine reverses multidrug resistance in Gram-negative bacteria carrying mobilized RND-type efflux pump gene cluster tmexCD-toprJ

To explore the impact of tmexCD1-toprJ1 expression on bacterial metabolomic state, tmexCD1-toprJ1 gene was cloned into a high-copy plasmid, pUC19, to generate pUC19-tmexCD1-toprJ1. An empty vector without tmexCD1-toprJ1 (pUC19) was included as the control. Subsequently, pUC19-tmexCD1-toprJ1 and pUC19 plasmid was transformed into reference strains K. pneumoniae K6. Then, we performed metabolomic profiling of tmexCD1-toprJ1-negative and -positive bacteria using liquid chromatography-mass spectrometry (LC-MS).