scholarly journals The polyaminoisoprenyl potentiator NV716 revives old disused antibiotics against intracellular forms of infection by Pseudomonas aeruginosa

2020 ◽  
pp. AAC.02028-20
Author(s):  
Gang W. Wang ◽  
Jean-Michel Brunel ◽  
Jean-Michel Bolla ◽  
Françoise Van Bambeke
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Efflux Pump ◽  
Hill Equation ◽  
Intrinsic Resistance ◽  
Bacterial Persistence ◽  
Response Curves ◽  
Active Efflux ◽  
Efflux Pump Inhibitors ◽  
The Hill ◽  
Multiple Antibiotics

Active efflux confers intrinsic resistance to multiple antibiotics in Pseudomonas aeruginosa, including old disused molecules. Beside resistance, intracellular survival is another reason for failure to eradicate bacteria with antibiotics. We evaluated the capacity of polyaminoisoprenyl potentiators (designed as efflux pump inhibitors [EPIs]) NV716 and NV731 compared to PAβN to restore the activity of disused antibiotics (doxycycline, chloramphenicol [substrates for efflux], rifampin [not substrate]) in comparison with ciprofloxacin against intracellular P. aeruginosa (strains with variable efflux levels) in THP-1 monocytes exposed during 24h to antibiotics alone (0.003-100x MIC) or combined with EPIs. Pharmacodynamic parameters (apparent static concentrations [Cs]; maximal relative efficacy [Emax]) were calculated using the Hill equation of concentration-response curves. PAβN and NV731 moderately reduced (0-4 doubling dilutions) antibiotic MICs but did not affect their intracellular activity. NV716 markedly reduced (1-16 doubling dilutions) the MIC of all antibiotics (substrates or not for efflux; strains expressing efflux or not); it improved their relative potency and maximal efficacy (lower Cs; more negative Emax) intracellularly. In parallel, NV716 reduced the persister fraction in stationary cultures when combined with ciprofloxacin. In contrast to PAβN and NV731 that act as EPIs against extracellular bacteria only, NV716 can resensitize P. aeruginosa to antibiotics whether substrates or not for efflux, both extracellularly and intracellularly. This suggests a complex mode of action that goes beyond a simple inhibition of efflux and reduces bacterial persistence. NV716 may appear as a useful adjuvant, including to disused antibiotics with low antipseudomonal activity, to improve their activity, including against intracellular P. aeruginosa.

scholarly journals MexAB-OprM Efflux Pump Interaction with the Peptidoglycan of Escherichia coli and Pseudomonas aeruginosa

2021 ◽  
Vol 22 (10) ◽  
pp. 5328
Author(s):  
Miao Ma ◽  
Margaux Lustig ◽  
Michèle Salem ◽  
Dominique Mengin-Lecreulx ◽  
Gilles Phan ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Pseudomonas Aeruginosa ◽  
Cell Division ◽  
Membrane Proteins ◽  
Outer Membrane ◽  
Efflux Pump ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
Active Efflux

One of the major families of membrane proteins found in prokaryote genome corresponds to the transporters. Among them, the resistance-nodulation-cell division (RND) transporters are highly studied, as being responsible for one of the most problematic mechanisms used by bacteria to resist to antibiotics, i.e., the active efflux of drugs. In Gram-negative bacteria, these proteins are inserted in the inner membrane and form a tripartite assembly with an outer membrane factor and a periplasmic linker in order to cross the two membranes to expulse molecules outside of the cell. A lot of information has been collected to understand the functional mechanism of these pumps, especially with AcrAB-TolC from Escherichia coli, but one missing piece from all the suggested models is the role of peptidoglycan in the assembly. Here, by pull-down experiments with purified peptidoglycans, we precise the MexAB-OprM interaction with the peptidoglycan from Escherichia coli and Pseudomonas aeruginosa, highlighting a role of the peptidoglycan in stabilizing the MexA-OprM complex and also differences between the two Gram-negative bacteria peptidoglycans.

Ultraviolet irradiation sensitizes Pseudomonas aeruginosa PAO1 to multiple antibiotics

2018 ◽  
Vol 4 (12) ◽  
pp. 2051-2057 ◽  
Author(s):  
Fuzheng Zhao ◽  
Qing Hu ◽  
Hongqiang Ren ◽  
Xu-Xiang Zhang
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Antibiotic Resistance ◽  
Uv Irradiation ◽  
Resistance Genes ◽  
Ultraviolet Irradiation ◽  
Efflux Pump ◽  
Antibiotic Resistance Genes ◽  
Regulatory System ◽  
Pseudomonas Aeruginosa Pao1 ◽  
Multiple Antibiotics

UV irradiation disturbs the regulatory system of efflux pump proteins to sensitize P. aeruginosa to multiple antibiotics. The increasing susceptibility to rifampicin and vancomycin might be caused by UV-mediated mutations in antibiotic resistance genes.

scholarly journals Involvement of an Active Efflux System in the Natural Resistance of Pseudomonas aeruginosa to Aminoglycosides

1999 ◽  
Vol 43 (11) ◽  
pp. 2624-2628 ◽  
Author(s):  
Julio Ramos Aires ◽  
Thilo Köhler ◽  
Hiroshi Nikaido ◽  
Patrick Plésiat
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Regulatory Gene ◽  
Natural Resistance ◽  
Insertion Mutagenesis ◽  
Detectable Effect ◽  
Efflux System ◽  
Intrinsic Resistance ◽  
Cloning And Sequencing ◽  
Active Efflux ◽  
Energy Dependent

ABSTRACT A mutant, named 11B, hypersusceptible to aminoglycosides, tetracycline, and erythromycin was isolated after Tn501insertion mutagenesis of Pseudomonas aeruginosa PAO1. Cloning and sequencing experiments showed that 11B was deficient in an, at that time, unknown active efflux system that contains homologs of MexAB. This locus also contained a putative regulatory gene,mexZ, transcribed divergently from the efflux operon. Introduction of a recombinant plasmid that carries the genes of the efflux system restored the resistance of 11B to parental levels, whereas overexpression of these genes strongly increased the MICs of substrate antibiotics for the PAO1 host. Antibiotic accumulation studies confirmed that this new system is an energy-dependent active efflux system that pumps out aminoglycosides. Furthermore, this system appeared to function with an outer membrane protein, OprM. While the present paper was being written and reviewed, genes with a sequence identical to our pump genes, mexXY of P. aeruginosa, have been reported to increase resistance to erythromycin, fluoroquinolones, and organic cations inEscherichia coli hosts, although efflux of aminoglycosides was not examined (Mine et al., Antimicrob. Agents Chemother. 43:415–417, 1999). Our study thus shows that the MexXY system plays an important role in the intrinsic resistance of P. aeruginosato aminoglycosides. Although overexpression of MexXY increased the level of resistance to fluoroquinolones, disruption of themexXY operon in P. aeruginosa had no detectable effect on susceptibility to these agents.

MexAB-OprM-Specific efflux pump inhibitors in Pseudomonas aeruginosa. Part 1: Discovery and early strategies for lead optimization

2003 ◽  
Vol 13 (23) ◽  
pp. 4201-4204 ◽  
Author(s):  
Kiyoshi Nakayama ◽  
Yohei Ishida ◽  
Masami Ohtsuka ◽  
Haruko Kawato ◽  
Ken-ichi Yoshida ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Efflux Pump ◽  
Lead Optimization ◽  
Efflux Pump Inhibitors

scholarly journals Pseudomonas aeruginosa Polynucleotide Phosphorylase Controls Tolerance to Aminoglycoside Antibiotics by Regulating the MexXY Multidrug Efflux Pump

2020 ◽  
Author(s):  
Zheng Fan ◽  
Xiaolei Pan ◽  
Dan Wang ◽  
Ronghao Chen ◽  
Tongtong Fu ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Bacterial Resistance ◽  
Efflux Pump ◽  
Opportunistic Pathogen ◽  
Aminoglycoside Antibiotics ◽  
Polynucleotide Phosphorylase ◽  
Multidrug Efflux ◽  
Intrinsic Resistance ◽  
Multidrug Efflux Pump ◽  
Fluoroquinolone Antibiotics

Pseudomonas aeruginosa is an opportunistic pathogen that shows high intrinsic resistance to a variety of antibiotics. The MexX-MexY-OprM efflux pump plays an important role in the bacterial resistance to aminoglycoside antibiotics. Polynucleotide phosphorylase (PNPase) is a highly conserved exonuclease that plays important roles in RNA processing and bacterial response to environmental stresses. Previously, we demonstrated that PNPase controls the tolerance to fluoroquinolone antibiotics by influencing the production of pyocin in P. aeruginosa. In this study, we found that mutation of the PNPase coding gene (pnp) in P. aeruginosa increases the bacterial tolerance to aminoglycoside antibiotics. We further demonstrate that upregulation of the mexXY genes is responsible for the increased tolerance in the pnp mutant. Furthermore, our experimental results revealed that PNPase controls translation of the armZ mRNA through its 5′ untranslated region (5′-UTR). ArmZ had previously been shown to positively regulate the expression of mexXY. Therefore, our results revealed a novel role of PNPase in the regulation of armZ and subsequently the MexXY efflux pump.

Peptidomimetics of Efflux Pump Inhibitors Potentiate the Activity of Levofloxacin in Pseudomonas aeruginosa

2002 ◽  
Vol 12 (5) ◽  
pp. 763-766 ◽  
Author(s):  
Thomas E. Renau ◽  
Roger Léger ◽  
Rose Yen ◽  
Miles W. She ◽  
Eric M. Flamme ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Efflux Pump ◽  
Efflux Pump Inhibitors

scholarly journals Pharmacodynamics of TRPV1 Agonists in a Bioassay Using Human PC-3 Cells

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Daniel Alvarez-Berdugo ◽  
Marcel Jiménez ◽  
Pere Clavé ◽  
Laia Rofes
Keyword(s):  
Sensory Neurons ◽  
Fluorescence Emission ◽  
Hill Equation ◽  
Hill Coefficient ◽  
Response Curves ◽  
Trpv1 Receptor ◽  
Specific Antagonist ◽  
Emission Changes ◽  
The Hill

Purpose. TRPV1 is a multimodal channel mainly expressed in sensory neurons. We aimed to explore the pharmacodynamics of the TRPV1 agonists, capsaicin, natural capsaicinoids, and piperine in anin vitrobioassay using human PC-3 cells and to examine desensitization and the effect of the specific antagonist SB366791.Methods. PC-3 cells expressing TRPV1 were incubated with Fluo-4. Fluorescence emission changes following exposition to agonists with and without preincubation with antagonists were assessed and referred to maximal fluorescence following the addition of ionomycin. Concentration-response curves were fitted to the Hill equation.Results. Capsaicin and piperine had similar pharmacodynamics (Emax204.8 ± 184.3% piperine versus 176.6 ± 35.83% capsaicin,P=0.8814, Hill coefficient 0.70 ± 0.50 piperine versus 1.59 ± 0.86 capsaicin,P=0.3752). In contrast, capsaicinoids had lowerEmax(40.99 ± 6.14% capsaicinoids versus 176.6 ± 35.83% capsaicin,P<0.001). All the TRPV1 agonists showed significant desensitization after the second exposition and their effects were strongly inhibited by SB366791.Conclusion. TRPV1 receptor is successfully stimulated by capsaicin, piperine, and natural capsaicinoids. These agonists present desensitization and their effect is significantly reduced by a TRPV1-specific antagonist. In addition, PC-3 cell bioassays proved useful in the study of TRPV1 pharmacodynamics.

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