scholarly journals Fis, an accessorial factor for transcriptional activation of the mar (multiple antibiotic resistance) promoter of Escherichia coli in the presence of the activator MarA, SoxS, or Rob.

1997 ◽  
Vol 179 (23) ◽  
pp. 7410-7419 ◽  
Author(s):  
R G Martin ◽  
J L Rosner
Keyword(s):  
Escherichia Coli ◽  
Antibiotic Resistance ◽  
Transcriptional Activation ◽  
Multiple Antibiotic Resistance

scholarly journals Inhibition of the multiple antibiotic resistance (mar) operon in Escherichia coli by antisense DNA analogs.

1997 ◽  
Vol 41 (12) ◽  
pp. 2699-2704 ◽  
Author(s):  
D G White ◽  
K Maneewannakul ◽  
E von Hofe ◽  
M Zillman ◽  
W Eisenberg ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Antibiotic Resistance ◽  
Antisense Oligonucleotides ◽  
Multiple Antibiotic Resistance ◽  
Wild Type ◽  
Lacz Expression ◽  
E Coli ◽  
Plasmid Construct ◽  
Dna Analogs ◽  
Susceptibility And Resistance

The multiple antibiotic resistance operon (marORAB) in Escherichia coli controls intrinsic susceptibility and resistance to multiple, structurally different antibiotics and other noxious agents. A plasmid construct with marA cloned in the antisense direction reduced LacZ expression from a constitutively expressed marA::lacZ translational fusion and inhibited the induced expression of LacZ in cells bearing the wild-type repressed fusion. The marA antisense construction also decreased the multiple antibiotic resistance of a Mar mutant. Two antisense phosphorothioate oligonucleotides, one targeted to marO and the other targeted to marA of the mar operon, introduced by heat shock or electroporation reduced LacZ expression in the strain having the marA::lacZ fusion. One antisense oligonucleotide, tested against a Mar mutant of E. coli ML308-225, increased the bactericidal activity of norfloxacin. These studies demonstrate the efficacy of exogenously delivered antisense oligonucleotides targeted to the marRAB operon in inhibiting expression of this chromosomal regulatory locus.

The association of acetylacetate (Acr AB-Tol C) and QepA genes with multiple antibiotic resistance among Escherichia coli clinical isolates

2019 ◽  
Vol 31 (3) ◽  
pp. 159-164
Author(s):  
Yaqdhan Alnomani ◽  
Abdolmajid Ghasemian ◽  
Mojtaba Memariani ◽  
Majid Eslami ◽  
Abdolreza Sabokrouh ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Antibiotic Resistance ◽  
Clinical Isolates ◽  
Multiple Antibiotic Resistance

scholarly journals Constitutive soxR Mutations Contribute to Multiple-Antibiotic Resistance in Clinical Escherichia coli Isolates

2005 ◽  
Vol 49 (7) ◽  
pp. 2746-2752 ◽  
Author(s):  
Anastasia Koutsolioutsou ◽  
Samuel Peña-Llopis ◽  
Bruce Demple
Keyword(s):  
Nitric Oxide ◽  
Escherichia Coli ◽  
Antibiotic Resistance ◽  
Dna Sequences ◽  
Single Point ◽  
Constitutive Expression ◽  
Clinical Isolates ◽  
Multiple Antibiotic Resistance ◽  
E Coli ◽  
First Time

ABSTRACT The soxRS regulon of Escherichia coli and Salmonella enterica is induced by redox-cycling compounds or nitric oxide and provides resistance to superoxide-generating agents, macrophage-generated nitric oxide, antibiotics, and organic solvents. We have previously shown that constitutive expression of soxRS can contribute to quinolone resistance in clinically relevant S. enterica. In this work, we have carried out an analysis of the mechanism of constitutive soxS expression and its role in antibiotic resistance in E. coli clinical isolates. We show that constitutive soxS expression in three out of six strains was caused by single point mutations in the soxR gene. The mutant SoxR proteins contributed to the multiple-antibiotic resistance phenotypes of the clinical strains and were sufficient to confer multiple-antibiotic resistance in a fresh genetic background. In the other three clinical isolates, we observed, for the first time, that elevated soxS expression was not due to mutations in soxR. The mechanism of such increased soxS expression remains unclear. The same E. coli clinical isolates harbored polymorphic soxR and soxS DNA sequences, also seen for the first time.

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