Journal article
Molecular basis for the increased polymyxin susceptibility of Klebsiella pneumoniae strains with under-acylated lipid A
Tony Velkov, Rachel L Soon, Pei L Chong, Johnny X Huang, Matthew A Cooper, Mohammad AK Azad, Mark A Baker, Philip E Thompson, Kade Roberts, Roger L Nation, Abigail Clements, Richard A Strugnell, Jian Li
Innate Immunity | SAGE Publications | Published : 2013
Abstract
The impact of under-acylation of lipid A on the interaction between Klebsiella pneumoniae LPS and polymyxins B and E was examined with fluorometric and calorimetric methods, and by 1 H NMR, using a paired wild type (WT) and the Δ lpxM mutant strains B5055 and B5055Δ lpxM, which predominantly express LPS with hexa- and penta-acylated lipid A structures respectively. LPS from B5055Δ lpxM displayed a fourfold increased binding affinity for polymyxins B and E compared with the B5055 WT LPS. EC 50 values were consistent with polymyxin minimum inhibitory concentration (MIC) values for each strain. Accordingly, polymyxi..
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