The in vivo effect of mutations at the aperture tip region of MdsC in the absence of functional MdsA, MdsB, and TolCa.

aThe in vivo effect of mutations in the aperture tip region of MdsC when wild-type MdsA and MdsB were disrupted was determined by measuring the resistance of the ATCC14028SΔacrABΔmdsABC::Cm5ΔtolC::Tn10 strain to several substrates. MdsC and its variants were expressed from pMdsC2, pMdsC2-G220A, pMdsC2-G433A, and pMdsC2-L441R.bAll MIC measurements were done in triplicate. The concentrations of crystal violet and acriflavine used to determine the MICs were 0, 1, 2, 4, 8, 16, and 32 µg/mL. The concentrations of rhodamine 6G and methylene blue used to determine the MICs were 0, 4, 8, 16, 32, 64, 128, and 256 µg/mL. The vancomycin concentrations used to determine the MICs were 0, 300, 400, 500, 600, 700, and 800 µg/mL.