biostudies-literatureUnknown12Loutet SACanadian Institutes of Health Research<h4>Background</h4>Burkholderia cenocepacia is a Gram-negative opportunistic pathogen displaying high resistance to antimicrobial peptides and polymyxins. We identified mechanisms of resistance by analyzing transcriptional changes to polymyxin B treatment in three isogenic B. cenocepacia strains with diverse polymyxin B resistance phenotypes: the polymyxin B-resistant parental strain K56-2, a polymyxin B-sensitive K56-2 mutant strain with heptoseless lipopolysaccharide (LPS) (RSF34), and a derivative of RSF34 (RSF34 4000B) isolated through multiple rounds of selection in polymyxin B that despite having a heptoseless LPS is highly polymyxin B-resistant.<h4>Results</h4>A heptoseless LPS mutant of B. cenocepacia was passaged through multiple rounds of selection to regain high levels of polymyBMC genomics472https://www.ebi.ac.uk/biostudies/studies/S-EPMC3190405biostudies-literatureTranscriptional responses of Burkholderia cenocepacia to polymyxin B in isogenic strains with diverse polymyxin B resistance phenotypes.PMC3190405Molinaro AValvano MAClarke CDi Lorenzo FLoutet SAfalseTranscriptional responses of Burkholderia cenocepacia to polymyxin B in isogenic strains with diverse polymyxin B resistance phenotypes.<h4>Background</h4>Burkholderia cenocepacia is a Gram-negative opportunistic pathogen displaying high resistance to antimicrobial peptides and polymyxins. We identified mechanisms of resistance by analyzing transcriptional changes to polymyxin B treatment in three isogenic B. cenocepacia strains with diverse polymyxin B resistance phenotypes: the polymyxin B-resistant parental strain K56-2, a polymyxin B-sensitive K56-2 mutant strain with heptoseless lipopolysaccharide (LPS) (RSF34), and a derivative of RSF34 (RSF34 4000B) isolated through multiple rounds of selection in polymyxin B that despite having a heptoseless LPS is highly polymyxin B-resistant.<h4>Results</h4>A heptoseless LPS mutant of B. cenocepacia was passaged through multiple rounds of selection to regain high levels of polymy2011-01-01T00:00:00Z2011 Sep2026-04-07T17:30:21.973Z2019-03-27T00:44:48ZS-EPMC31904052195532610.1186/1471-2164-12-472