# Components of the LPS modification system (mgrB
, phoP, phoQ, and the pmr operon) are present in the annotated genome of C.
Moreover, insertion of mobile element IS5 in the mgrB gene was detected, which is also associated with colistin resistance (5).
In vivo emergence of colistin resistance in Klebsiella pneumoniae producing KPC-type carbapenemases mediated by insertional inactivation of the PhoQ/PhoP mgrB regulator.
Resistance genes identified by whole-genome sequencing of an ESBL-producing mcr-1-positive Klebsiella pneumoniae strain isolated from a 38-year-old man, France * Resistance gene Target antimicrobial drug mcr-1 and inactivation of Colistin mgrB by IS5 insertion [bla.sub.SHV-106] [beta]-lactams aac(3)-IId and aadA16-like Aminoglycoside aac(6')Ib-cr Quinolone and aminoglycoside fosA5 Fosfomycin sulI and folP Sulfonamide dfrA27 Trimethoprim tetD Tetracycline * ESBL, extended-spectrum [beta]-lactamase.
We sequenced the pmrA, pmrB, phoP, phoQ, and mgrB genes possibly involved in colistin resistance in K.
isolates, resistance to colistin was associated with various chromosomal gene changes responsible for lipopolysaccharide modifications (online Technical Appendix): 10 isolates had mutations in the PmrAB two-component system (n = 3 in pmrA gene, n = 7 in pmrB gene); 2 isolates had structural modifications in the PhoPQ two-component system (n = 1 in phoP gene, n = 1 inphoQ gene); and 75 isolates had various alterations in mgrB gene, the negative regulator of the PhoPQ system (online Technical Appendix).