Proteomic profiling of carbapenemase (KPC)-producer after induced polymyxin resistance.

To elucidate the changes in protein expression associated with polymyxin resistance in , we profiled a comparative proteomic analysis of polymyxin B-resistant mutants KPC-2-producing , and of its susceptible counterparts. Two-dimensional reversed phase nano ultra-performance liquid chromatography mass spectrometry was used for proteomic analysis. Our results showed that the proteomic profile involved several biological processes, and we highlight the downregulation of outer membrane protein A (OmpA) and the upregulation of SlyB outer membrane lipoprotein (conserved protein member of the PhoPQ regulon) and AcrA multidrug efflux pump in polymyxin B-resistant strains. Our results highlight the possible participation of the SlyB, AcrA and OmpA proteins in the determination of polymyxin B heteroresistance in KPC-2-producing