Carbon Storage Regulator A (CsrA) is an RNA binding protein that acts as a global regulator of diverse genes. Using a combination of genetics and biochemistry we show that CsrA binds directly to the 5' end of the transcript encoding AcrAB. Deletion of csrA or mutagenesis of the CsrA binding sites reduced production of both AcrA and AcrB. Nucleotide substitutions at the 5' UTR of acrA mRNA that ...

A carbapenem resistant but ceftriaxone and cefepime susceptible Klebsiella oxytoca was isolated from the blood of a patient with polymicrobial bacteremia after 2 weeks of ertapenem treatment. Whole-genome sequencing identified no carbapenemase gene nor plasmid, but only blaOXY-2-8 gene with a mutation in the promoter that's been reported to increase its expression. Two other specific carbapenem...

The AcrA/AcrB/TolC complex spans the inner and outer membranes of Escherichia coli and serves as its major drug-resistance pump. Driven by the proton motive force, it mediates the efflux of bile salts, detergents, organic solvents, and many structurally unrelated antibiotics. Here, we report a crystallographic structure of trimeric AcrB determined at 2.9 and 3.0 angstrom resolution in space gro...

In previous work, we discovered that: 1) tolC was absolutely required not only for pathogenicity, but also for survival of Xylella fastidiosa (Xf) strain Temecula in Vitis vinifera grapevines; 2) that the loss of multi-drug resistance (MDR) efflux through the Type I secretion system was the primary reason that tolC Temecula could not survive in grapevines, and 3) that gene knockouts of Type I s...

26 Control of membrane permeability is a key step in regulating the intracellular 27 concentration of antibiotics. Efflux pumps confer innate resistance to a wide 28 range of toxic compounds such as antibiotics, dyes, detergents and 29 disinfectants in members of the Enterobacteriaceae. The AcrAB-TolC efflux 30 pump is involved in multidrug resistance in E. cloacae. However, the underlying 31 m...

Periplasmic adaptor proteins are key components of bacterial tripartite efflux pumps. The 2.85 Å resolution structure of an MFS (major facilitator superfamily) pump adaptor, Aquifex aeolicus EmrA, shows linearly arranged α-helical coiled-coil, lipoyl, and β-barrel domains, but lacks the fourth membrane-proximal domain shown in other pumps to interact with the inner membrane transporter. The ada...