Polymyxin B and polymyxin B nonapeptide alter cytoplasmic membrane permeability in Escherichia coli

1986 ◽  
Vol 18 (5) ◽  
pp. 557-563 ◽  
Author(s):  
Ronald A. Dixon ◽  
Ian Chopra
Keyword(s):  
Escherichia Coli ◽  
Membrane Permeability ◽  
Cytoplasmic Membrane ◽  
Polymyxin B

scholarly journals Stages of Polymyxin B Interaction with theEscherichia coli Cell Envelope

2000 ◽  
Vol 44 (11) ◽  
pp. 2969-2978 ◽  
Author(s):  
Rimantas Daugelavičius ◽  
Elena Bakiene˙ ◽  
Dennis H. Bamford
Keyword(s):  
Escherichia Coli ◽  
Pore Formation ◽  
Cytoplasmic Membrane ◽  
Cell Envelope ◽  
Polymyxin B ◽  
Bactericidal Effect ◽  
Bactericidal Action ◽  
Lipophilic Compounds ◽  
Permeability Characteristics ◽  
New Findings

ABSTRACT The effects of polymyxin B (PMB) on the Escherichia coli outer (OM) and cytoplasmic membrane (CM) permeabilities were studied by monitoring the fluxes of tetraphenylphosphonium, phenyldicarbaundecaborane, and K+ and H+ions. At concentrations between 2 and 20 μg/ml, PMB increased the OM permeability to lipophilic compounds and induced a leakage of K+ from the cytosol and an accumulation of lipophilic anions in the cellular membranes but did not cause the depolarization of the CM. At higher concentrations, PMB depolarized the CM, forming ion-permeable pores in the cell envelope. The permeability characteristics of PMB-induced pores mimic those of bacteriophage- and/or bacteriocin-induced channels. However, the bactericidal effect of PMB took place at concentrations below 20 μg/ml, indicating that this effect is not caused by pore formation. Under conditions of increased ionic strength, PMB made the OM permeable to lipophilic compounds and decreased the K+gradient but was not able to depolarize the cells. The OM-permeabilizing effect of PMB can be diminished by increasing the concentration of Mg2+. The major new findings of this work are as follows: (i) the OM-permeabilizing action of PMB was dissected from its depolarizing effect on the CM, (ii) the PMB-induced ion-permeable pores in bacterial envelope were registered, and (iii) the pore formation and depolarization of the CM are not obligatory for the bactericidal action of PMB and dissipation of the K+gradient on the CM.

scholarly journals Sensitization of Staphylococcus aureus and Escherichia coli to Antibiotics by the Sesquiterpenoids Nerolidol, Farnesol, Bisabolol, and Apritone

2003 ◽  
Vol 47 (10) ◽  
pp. 3357-3360 ◽  
Author(s):  
Byron F. Brehm-Stecher ◽  
Eric A. Johnson
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Flow Cytometry ◽  
Cytoplasmic Membrane ◽  
Polymyxin B ◽  
Live Cells ◽  
Antimicrobial Compounds ◽  
Intracellular Accumulation ◽  
Low Concentrations ◽  
Nucleic Acid Stain

ABSTRACT The sesquiterpenoids nerolidol, farnesol, bisabolol, and apritone were investigated for their abilities to enhance bacterial permeability and susceptibility to exogenous antimicrobial compounds. Initially, it was observed by flow cytometry that these sesquiterpenoids promoted the intracellular accumulation of the membrane-impermeant nucleic acid stain ethidium bromide by live cells of Lactobacillus fermentum, suggesting that enhanced permeability resulted from disruption of the cytoplasmic membrane. The ability of these sesquiterpenoids to increase bacterial susceptibility to a number of clinically important antibiotics was then investigated. In disk diffusion assays, treatment with low concentrations (0.5 to 2 mM) of nerolidol, bisabolol, or apritone enhanced the susceptibility of Staphylococcus aureus to ciprofloxacin, clindamycin, erythromycin, gentamicin, tetracycline, and vancomycin. Nerolidol and farnesol also sensitized Escherichia coli to polymyxin B. Our results indicate the practical utility of sensitizing bacteria to antimicrobials with sesquiterpenoids that have traditionally been used as flavorants and aroma compounds in the food and perfume industries.

scholarly journals The dynamics of assembly of a cytoplasmic membrane protein in Escherichia coli.

1992 ◽  
Vol 267 (8) ◽  
pp. 5339-5345
Author(s):  
B Traxler ◽  
C Lee ◽  
D Boyd ◽  
J Beckwith
Keyword(s):  
Escherichia Coli ◽  
Membrane Protein ◽  
Cytoplasmic Membrane

Interaction of Gram-Negative Bacteria with the Lysosomal Fraction of Polymorphonuclear Leukocytes II. Changes in the Cell Envelope of Escherichia coli

1970 ◽  
Vol 1 (3) ◽  
pp. 311-318
Author(s):  
D. Friedberg ◽  
I. Friedberg ◽  
M. Shilo
Keyword(s):  
Escherichia Coli ◽  
Polymorphonuclear Leukocytes ◽  
Cytoplasmic Membrane ◽  
Morphological Changes ◽  
Cell Envelope ◽  
Gram Negative Bacteria ◽  
Intact Cells ◽  
Lysosomal Fraction ◽  
E Coli ◽  
Absorbing Material

Interaction of lysosomal fraction with Escherichia coli caused damage to the cell envelope of these intact cells and to the cytoplasmic membrane of E. coli spheroplasts. The damage to the cytoplasmic membrane was manifested in the release of 260-nm absorbing material and β-galactosidase from the spheroplasts, and by increased permeability of cryptic cells to O -nitrophenyl-β- d -galactopyranoside; damage to the cell wall was measured by release of alkaline phosphatase. Microscope observation showed morphological changes in the cell envelope.

Two Novel Mutations Associated with Polymyxin-B Resistance in a Pandemic Lineage of Uropathogenic Escherichia coli of the Sequence Type 69

Chemotherapy ◽  
2021 ◽  
pp. 1-7
Author(s):  
Carla Adriana dos Santos ◽  
Rodrigo Tavanelli Hernandes ◽  
Marcos Paulo Vieira Cunha ◽  
Filipe Onishi Nagamori ◽  
Claudia Regina Gonçalves ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Susceptibility Testing ◽  
Polymyxin B ◽  
Antimicrobial Treatment ◽  
Sequence Type ◽  
Broth Microdilution ◽  
Economic Costs ◽  
Novel Mutations ◽  
E Coli ◽  
Total Inhibition

<b><i>Background:</i></b> Uropathogenic <i>Escherichia coli</i> (UPEC) are frequent pathogens worldwide, impacting on the morbidity and economic costs associated with antimicrobial treatment. <b><i>Objectives:</i></b> We report two novel mutations associated with polymyxin-B resistance in an UPEC isolate collected in 2019. <b><i>Methods:</i></b> Isolate was submitted to antimicrobial susceptibility testing including broth microdilution for polymyxin B. Whole genome was sequenced and analyzed. <b><i>Results:</i></b> Polymyxin-B total inhibition occurred at 16 mg/L (resistant). UPEC isolate was assigned to the phylogroup D, serotype O117:H4, and Sequence Type 69. <i>mcr</i> genes were not detected, but two novel mutations in the <i>pmrA/basS</i> (A80S) and <i>pmrB/</i>basR (D149N) genes were identified. <b><i>Conclusions:</i></b> The occurrence of non-<i>mcr</i> polymyxin resistance in <i>E. coli</i> from extraintestinal infections underscores the need of a continuous surveillance of this evolving pathogen.

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