Supplementary Material for: Relationship between Adaptive Changing of Lysophosphatidylethanolamine Content in the Bacterial Envelope and Ampicillin Sensitivity of Yersinia pseudotuberculosis

The low permeability of porin channels is the possible reason for Gram-negative bacterial resistance to antibiotics. The adaptive accumulation of lysophosphatidylethanolamine (LPE) in Yersinia pseudotuberculosis induces conformational changes of OmpF porin that may hinder the transport of antibiotics through this channel. The present study was aimed to test whether the changes in LPE content affect the resistance of bacteria to ampicillin. The addition of glucose to the culture medium was shown to simultaneously increase the level of LPE and minimum inhibitory concentration (MIC) for ampicillin of Y. pseudotuberculosis cells 6- and 2-fold, respectively. However, the coadministration of glucose and polyphenol extract from buckwheat husks reduced the content of LPE 2-fold and restored MIC to the control value. Thus, PBEH can be used as antibiotic adjuvant to improve an antibiotic’s ability to cross the outer membrane. The present work demonstrated: (i) the role of adaptive changes in the lipid composition of Y. pseudotuberculosis in the development of antibiotic resistance, and (ii) the promising use of PBEH in combination therapy to increase the susceptibility of Gram-negative bacteria to the conventional β-lactam antibiotics, probably attenuating in vivo a previously demonstrated effect of LPE on the conformation and function of the OmpF channel.