RamA upregulates the ATP-binding cassette transporter <i>mlaFEDCB</i> to mediate resistance to tetracycline-class antibiotics and the stability of membranes in <i>Klebsiella pneumoniae</i>

Multidrug-resistant and extensively drug-resistant <i>Klebsiella pneumoniae</i> have emerged as significant global health concerns resulting in high mortality rates. Although previous research has investigated the maintenance of lipid asymmetry (Mla) pathway, the extent to which it mediates antimicrobial resistance in <i>K. pneumoniae</i> and the underlying upstream regulatory mechanisms remain unclear. In this study, we sought to determine at the molecular level how the AraC-type global regulator RamA directly regulates mlaFEDCB, which mediates resistance to tetracycline-class antibiotics and the stability of bacterial membranes in <i>K. pneumoniae</i>.