New insights in novel Escherichia coli colistin resistant strains isolated from Argentina

MATURANA, PATRICIA; SEMORILE, LILIANA; MARTINEZ, MELINA; MAFFIA, P; FACCONE, DIEGO ; HOLLMANN, AXEL

EUROPEAN BIOPHYSICS JOURNAL WITH BIOPHYSICS LETTERS

SPRINGER

Lugar: Berlin; Año: 2020 vol. 49 p. 307 - 313

0175-7571

Colistin is a polymyxin antibiotic (polymyxin E), that in the last years has re-emerged as an option treatment for multidrug-resistant (MDR) bacteria. Recently, the re-introduction of colistin resulted in the appearance of colistin-resistant bacteria, which is usually caused by LPS modifications. The fact that this modification is mediated by a plasmid carrying mcr-1 gen, imply a horizontal transfer of colistin resistance. In Argentina, the National Reference Laboratory in Antimicrobial Resistance (NRLAR), has recently screened several bacteria for mcr-1 plasmid, detecting nine Escherichia coli isolates carrying the plasmid with the mcr-1gen, among others. In this context, we proposed to assess the effect of surface charges modifications induced by the plasmid MCR-1 and its impact on the resulting colistin resistance in two clinical isolates of colistin resistant E.coli. Using zeta potential assays, we confirmed the reduction of negative exposure charges on clinical isolates compared to the reference strain of E. coli. In addition, through permeabilization assays we were able to correlate this exposure charges reduction with the extent of damage in the bacterial membrane. Furthermore, the fact that this surface charge modification through substitution of Lipid A is plasmid encoded, represents an important concern in the future of antimicrobial peptide drug development.