Figure 1.

PmrAB-mediated PMB resistance and pmrC expression levels. (a) Genomic organization of the pmrCAB operon. pmrB mutations in the highly PMB-resistant clinical isolates. PmrB domains: TM1, first transmembrane domain (aa 10–29); PD, periplasmic domain (aa 29–142); TM2, second transmembrane domain (aa 142–164); HAMP, histidine kinases, adenylylcyclases, methyl-binding proteins, and phosphatases (aa 145–214); and HATPase_c, histidine kinase-like ATPases (aa 326–437) [10]. The red letters indicate mutation locations in the NCCP 16007 strain. * novel site mutation in the PmrB. (b) Schematic representation of PMB resistance mechanism in Acinetobacter baumannii. (c) High expression of the pmrC gene in highly PMB-resistant clinical isolates (NCCP 15,995, NCCP 15,996, F-1629, and NCCP 16007 strains). The pmrC expression of the strains was normalized to their respective 16S rRNA expression. Data represent the mean (± standard deviation, SD; N = 3 biological replicates). *, P < 0.05; **, P < 0.01 by Student’s t-test against theoretical value