The pmrCAB operon mediates polymyxin resistance in Acinetobacter baumannii ATCC 17978 and clinical isolates through phosphoethanolamine modification of lipid A.

ABSTRACT: The emergence of multidrug resistance among Acinetobacter baumannii is leading to an increasing dependence on the use of polymyxins as last-hope antibiotics. Here, we utilized genetic and biochemical methods to define the involvement of the pmrCAB operon in polymyxin resistance in this organism. Sequence analysis of 16 polymyxin B-resistant strains, including 6 spontaneous mutants derived from strain ATCC 17978 and 10 clinical isolates from diverse sources, revealed that they had independent mutations in the pmrB gene, encoding a sensor kinase, or in the response regulator PmrA. Knockout of the pmrB gene in two mutants and two clinical isolates led to a decrease in the polymyxin B susceptibility of these strains, which could be restored with the cloned pmrAB genes from the mutants but not

SUBMITTER: Arroyo LA 

PROVIDER: S-EPMC3147623 | biostudies-literature | 2011 Aug

REPOSITORIES: biostudies-literature