scholarly journals Antistaphylococcal Activity of Extracts, Fractions, and Compounds of Acacia polyacantha Wild (Fabaceae)

2020 ◽  
Vol 2020 ◽  
pp. 1-10 ◽  
Author(s):  
Fred A. Ashu ◽  
Jean Na-Iya ◽  
Brice E. N. Wamba ◽  
Justin Kamga ◽  
Paul Nayim ◽  
...  
Keyword(s):  
Oleanolic Acid ◽  
Active Compound ◽  
Efflux Pump ◽  
Dependent Manner ◽  
Efflux Pump Inhibitor ◽  
Proton Atpase ◽  
Antistaphylococcal Activity ◽  
Broth Microdilution Method ◽  
Efflux Pump Inhibitors ◽  
Acacia Polyacantha

Acacia polyacantha is a medicinal plant traditionally used to treat livestock diseases and gastrointestinal infections; our study was undertaken to evaluate the antistaphylococcal activities of the methanolic leaf, bark, and root extracts, fractions, and compounds from Acacia polyacantha against a panel of 14 multidrug-resistant Staphylococcus bacterial strains overexpressing efflux pumps. The study was also extended to investigate two possible modes of action, that is, influence on bacterial growth kinetics and influence on proton-ATPase pumps, of the most active compound against a reference strain. Materials and Methods. The crude extracts after extraction were subjected to column chromatography. Antibacterial assays of extracts, fractions, and compounds alone and in the presence of efflux pump inhibitors were carried out using the broth microdilution method and the study of two mechanisms of action achieved by standard methods with the most active compound. Results. The phytochemical study of Acacia polyacantha leaves leads to the isolation of stigmasterol (1), β-amyrin (2), 3-O-methyl-D-chiro-inositol (3), epicatechin (4), quercetin-3-O-galactoside (5), 3-O-[β-D-xylopyranosyl-(1 ⟶ 4)-β-D-galactopyranosyl]-oleanolic acid (6), 3-O-[β-galactopyranosyl-(1⟶ 4)-β-D-galactopyranosyl]-oleanolic acid (7) and that of leaves lead to the isolation of lupeol (8) 2,3-dihydroxypropyltetracosanoate (9), and methyl-gallate (10). Leaf, root, and bark extracts inhibited 92.85% (13/14), 92.85% (13/14), and 71.43 % (10/14) of the tested bacteria strains, respectively, with minimum inhibitory concentration (MIC) varying between 16 and 1024 μg/mL. Fractions exhibited better activities compared to those of their extracts of origin, as their MICs ranged from 16 to 512 μg/mL, with fractions from leaves being more active than those obtained from barks. Compounds had varying activities; MICs varied from 16 to 512 μg/mL with compound 4 presenting the best activity as MICs ≤100 μg/mL were obtained against 11 of the tested bacteria. The activities of extracts, fractions, and compounds were improved in the presence of carbonyl cyanide m-chlorophenylhydrazone (CCCP) as an efflux pump inhibitor to as much as >128 folds. Meanwhile, in the presence of chlorpromazine as an efflux pump inhibitor, only the activity of compound 10 was improved on 10 of the tested bacteria strains. Compound 4 prolonged the lag phase of the growth kinetic in a concentration-dependent manner and equally inhibited the proton-ATPase pumps of the tested bacteria strains. Conclusion. The present study demonstrates the antistaphylococcal potential of Acacia polyacantha and its constituents to combat bacterial infections alone or in combination with efflux pump inhibitors.

scholarly journals Antibacterial and Antibiotic Modifying Potential of Crude Extracts, Fractions, and Compounds from Acacia polyacantha Willd. against MDR Gram-Negative Bacteria

2019 ◽  
Vol 2019 ◽  
pp. 1-13 ◽  
Author(s):  
Flora T. Mambe ◽  
Jean Na-Iya ◽  
Ghislain W. Fotso ◽  
Fred Ashu ◽  
Bathélémy Ngameni ◽  
...  
Keyword(s):  
Oleanolic Acid ◽  
Bacterial Infections ◽  
Efflux Pump ◽  
Synergistic Effects ◽  
Bacterial Species ◽  
Gram Negative Bacteria ◽  
Efflux Pump Inhibitor ◽  
Gram Negative ◽  
Acacia Polyacantha

The present study aimed to assess the in vitro antibacterial and antibiotic modifying activities of methanol extracts prepared from the leaf (APL) and bark (APB) of Acacia polyacantha, fractions (APLa-d) and compounds isolated from APL against a panel of multidrug resistant (MDR) Gram-negative bacteria. Leaf extract was subjected to column chromatography for compounds isolation; antibacterial assays were performed on samples alone and with an efflux pump inhibitor (EPI), respectively, and several antibiotics on the tested bacteria. The phytochemical investigation of APL led to the isolation of stigmasterol (1), β-amyrin (2), 3-O-β-D-glucopyranosylstigmasterol (3), 3-O-methyl-D-chiro-inositol (4), epicatechin (5), quercetin-3-O-glucoside (6), 3-O-[β-D-xylopyranosyl-(1→4)-β-D-galactopyranosyl]-oleanolic acid (7), and 3-O-[β-galactopyranosyl-(1→4)-β-D-galactopyranosyl]-oleanolic acid (8). APL and APB had minimal inhibitory concentration (MIC) values ≤ 1024 μg/mL on 73.3% and 46.7% of the tested bacteria, respectively. APLb and APLd were effective against 88.9% of tested bacterial species with compound 8 showing the highest activity inhibiting 88.9% of tested bacteria. The EPI, phenylalanine-arginine-β-naphthylamide (PAßN), strongly improved the activity of APL, APLb, APLd, and compound 8 on all tested bacteria. Synergistic effects were obtained when APL and compounds 7 and 8 were combined with erythromycin (ERY), gentamycin (GEN), ciprofloxacin (CIP), and norfloxacin (NOR). The present study demonstrates the antibacterial potential of Acacia polyacantha and its constituents to combat bacterial infections alone or in combination with EPI.

scholarly journals Role of efflux pump inhibitor in decreasing antibiotic cross-resistance of Pseudomonas aeruginosa in a burn hospital in Iran

2016 ◽  
Vol 10 (06) ◽  
pp. 600-604 ◽  
Author(s):  
Mahshid Talebi-Taher ◽  
َAli Majidpour ◽  
Abbas Gholami ◽  
Samira Rasouli-Kouhi ◽  
Maryam Adabi
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Efflux Pump ◽  
Efflux Pumps ◽  
Disk Diffusion ◽  
Diffusion Method ◽  
Cross Resistance ◽  
Beta Lactams ◽  
Efflux Pump Inhibitor ◽  
Efflux Pump Inhibitors

Introduction: Multidrug resistance in Pseudomonas aeruginosa may be due to efflux pump overexpression. This study phenotypically examined the role of efflux pump inhibitors in decreasing antibiotic cross-resistance between beta-lactams, fluoroquinolones, and aminoglycosides in P. aeruginosa isolates from burn patients in Iran. Methodology: A total of 91 phenotypically and genotypically confirmed P. aeruginosa samples were studied. Multidrug cross-resistance was determined using the disk diffusion method and minimum inhibitory concentration (MIC) test. The contribution of efflux pumps was determined by investigating MIC reduction assay to markers of beta-lactams, fluoroquinolones, and aminoglycosides in the absence and presence of an efflux pump inhibitor. All the isolates were also tested by polymerase chain reaction for the presence of mexA, mexC, and mexE efflux genes. Results: Of the isolates, 81 (89%) and 83 (91.2%) were multidrug resistant according to the disk diffusion and MIC method, respectively. Cross-resistance was observed in 67 (73.6%) and 68 (74.7%) of isolates according to the disk diffusion and MIC method, respectively. In the presence of the efflux pump inhibitor, twofold or higher MIC reduction to imipenem, cefepime, ciprofloxacin, and gentamicin was observed in 59, 65, 55, and 60 isolates, respectively. Except for two isolates that were negative for mexC, all isolates were positive for mexA, mexC, and mexE genes simultaneously. Conclusion: Efflux pumps could cause different levels of resistance based on their expression in clinical isolates. Early detection of different efflux pumps in P. aeruginosa could allow the use of other antibiotics and efflux pump inhibitors in combination with antibiotic therapy.

scholarly journals Mode of action of the 2-phenylquinoline efflux inhibitor PQQ4R againstEscherichia coli

PeerJ ◽  
2017 ◽  
Vol 5 ◽  
pp. e3168 ◽  
Author(s):  
Diana Machado ◽  
Laura Fernandes ◽  
Sofia S. Costa ◽  
Rolando Cannalire ◽  
Giuseppe Manfroni ◽  
...  
Keyword(s):  
Mode Of Action ◽  
Bacterial Infections ◽  
Efflux Pump ◽  
Resistant Bacteria ◽  
Gram Negative Bacteria ◽  
Synergistic Activity ◽  
Dependent Manner ◽  
Gram Negative ◽  
E Coli ◽  
Efflux Pump Inhibitors

Efflux pump inhibitors are of great interest since their use as adjuvants of bacterial chemotherapy can increase the intracellular concentrations of the antibiotics and assist in the battle against the rising of antibiotic-resistant bacteria. In this work, we have described the mode of action of the 2-phenylquinoline efflux inhibitor (4-(2-(piperazin-1-yl)ethoxy)-2-(4-propoxyphenyl) quinolone – PQQ4R), againstEscherichia coli,by studding its efflux inhibitory ability, its synergistic activity in combination with antibiotics, and compared its effects with the inhibitors phenyl-arginine-β-naphthylamide (PAβN) and chlorpromazine (CPZ). The results showed that PQQ4R acts synergistically, in a concentration dependent manner, with antibiotics known to be subject to efflux inE. colireducing their MIC in correlation with the inhibition of their efflux. Real-time fluorometry assays demonstrated that PQQ4R at sub-inhibitory concentrations promote the intracellular accumulation of ethidium bromide inhibiting its efflux similarly to PAβN or CPZ, well-known and described efflux pump inhibitors for Gram-negative bacteria and whose clinical usage is limited by their levels of toxicity at clinical and bacteriological effective concentrations. The time-kill studies showed that PQQ4R, at bactericidal concentrations, has a rapid antimicrobial activity associated with a fast decrease of the intracellular ATP levels. The results also indicated that the mode of action of PQQ4R involves the destabilization of theE. coliinner membrane potential and ATP production impairment, ultimately leading to efflux pump inhibition by interference with the energy required by the efflux systems. At bactericidal concentrations, membrane permeabilization increases and finally ATP is totally depleted leading to cell death. Since drug resistance mediated by the activity of efflux pumps depends largely on the proton motive force (PMF), dissipaters of PMF such as PQQ4R, can be regarded as future adjuvants of conventional therapy againstE. coliand other Gram-negative bacteria, especially their multidrug resistant forms. Their major limitation is the high toxicity for human cells at the concentrations needed to be effective against bacteria. Their future molecular optimization to improve the efflux inhibitory properties and reduce relative toxicity will optimize their potential for clinical usage against multi-drug resistant bacterial infections due to efflux.

scholarly journals Combination of Antibiotic, Efflux Pump Inhibitor and Autolysis Inhibitor Protects Mice from S. aureus Peritonitis by Inhibiting α-hemolysin-induced MAPKs/NF-κB/NLRP3 Activation

2019 ◽  
Author(s):  
Wenjing Luan ◽  
Xiaolei Liu ◽  
Xuefei Wang ◽  
Yanan An ◽  
Yang Wang ◽  
...  
Keyword(s):  
Drug Combination ◽  
Efflux Pump ◽  
Three Dimensional ◽  
Efflux Pump Inhibitor ◽  
Bacterial Colony ◽  
Antistaphylococcal Activity ◽  
Antibiotic Efflux ◽  
Anti Inflammation

Abstract Background: The infection of staphylococcus aureus (S. aureus) is difficult to treat, our aim was to investigate the antibacterial abilities of a combination of antibiotic cloxacillin, efflux pump inhibitor thioridazine and autolysis inhibitor tetracycline and its anti-inflammation properties through inhibiting α-hemolysin induced MAPKs/NF-κB/NLRP3 activation in vitro and in vivo. Methods: The antibacterial susceptibility test and three-dimensional checkerboard method were utilized to investigate the synergistic antibacterial activity of the three-drug combination cloxacillin/thioridazine/tetracycline, α-hemolysin test and scanning electron microscope were used to assay the inhibition effects of the combination on the secretion of α-hemolysin and membrane-derived vesicles production from S. aureus, Western blot and pharmacological inhibition assays were performed to test α-hemolysin -induced MAPKs/NF-κB/NLRP3 activation in macrophage in vitro. Results: In vitro, the three-drug combination showed synergistic antistaphylococcal activity; the subinhibitory concentration of the combination significantly inhibited the secretion of α-hemolysin related to the number of vesicles produced by S. aureus and significantly inhibited the expression of MAPKs/NF-κB/NLRP3 proteins in the macrophages induced by S. aureus α-hemolysin. In vivo, the drug combination significantly reduced bacterial colony-forming unit counts of the viscera in mouse peritonitis model of S. aureus infection, the combination therapy reduced the primary inflammatory pathology and the release of bacterial-stimulated cytokines such as IL-1β and TNF-α, and inhibited the expression of MAPKs/NF-κB/NLRP3 proteins in peritoneal macrophage. Conclusions: Combination of antibiotic, efflux pump inhibitor and autolysis inhibitor owns good antistaphylococcal activity and significantly inhibit staphylococcal α-hemolysin and its inflammation, thus, the combination is a novel strategy of antibacterial and anti-inflammation.

scholarly journals Pseudomonas Aeruginosa Antibiotic Efflux Pump Variants Exhibit Increased Virulence

2021 ◽  
Author(s):  
Mylene Vaillancourt ◽  
Sam P. Limsuwannarot ◽  
Catherine Bresee ◽  
Rahgavi Poopalarajah ◽  
Peter Jorth
Keyword(s):  
Gene Expression ◽  
Pseudomonas Aeruginosa ◽  
Efflux Pump ◽  
Infection Model ◽  
Dependent Manner ◽  
Resistance Mutations ◽  
Efflux Pump Inhibitor ◽  
Pump System ◽  
Mouse Infection Model ◽  
Epithelial Barriers

Antibiotic resistant Pseudomonas aeruginosa infections are the primary cause of mortality in people with cystic fibrosis (CF). Yet it has only recently become appreciated that resistance mutations can also increase P. aeruginosa virulence, even in the absence of antibiotics. Moreover, the mechanisms by which resistance mutations increase virulence are poorly understood. In this study we tested the hypothesis that mutations affecting efflux pumps can directly increase P. aeruginosa virulence. Using genetics, physiological assays, and model infections, we show that efflux pump mutations can increase virulence. Mutations of the mexEF efflux pump system increased swarming, rhamnolipid production, and lethality in a mouse infection model, while mutations in mexR that increased expression of the mexAB-oprM efflux system increased virulence during an acute murine lung infection without affecting swarming or rhamnolipid gene expression. Finally, we show that an efflux pump inhibitor, which represents a proposed novel treatment approach for P. aeruginosa, increased rhamnolipid gene expression in a dose-dependent manner. This finding is important because rhamnolipids are key virulence factors involved in dissemination through epithelial barriers and cause neutrophil necrosis. Together, these data show how current and proposed future anti-Pseudomonal treatments may unintentionally make infections worse by increasing virulence. Therefore, treatments that target efflux should be pursued with caution.

scholarly journals ANTICANCER DRUGS AS PROSPECTIVE EFFLUX PUMP INHIBITORS FOR SALMONELLA TYPHI PRODUCE CONFLICTING RESULTS IN IN SILICO AND IN VITRO STUDIES

2016 ◽  
Vol 8 (12) ◽  
pp. 244 ◽  
Author(s):  
Pranjali Gupta ◽  
Pankaj Gautam ◽  
Nishant Rai
Keyword(s):  
Anticancer Drugs ◽  
In Silico ◽  
Efflux Pump ◽  
Three Dimensional ◽  
Antimicrobial Effect ◽  
Fixed Time ◽  
Efflux Pump Inhibitor ◽  
Conflicting Result ◽  
Efflux Pump Inhibitors

<p><strong>Objective: </strong>Anticancer drugs paclitaxel and vinblastine were tested for their potential as efflux pump inhibitors for <em>Salmonella</em> Typhi-based on <em>in silico</em> and <em>in vitro</em> studies.</p><p><strong>Methods: </strong>Three-dimensional protein models of AcrAB-TolC of <em>Salmonella</em> Typhi were generated by online server PHYRE-2. The quality of 3D structures was assessed by PROCHECK, SWISS MODEL. Docking analysis of anticancer drugs with AcrA, AcrB and TolC subunits were performed after refining the homology models with Modrefiner. <em>Salmonella</em> Typhi (<em>S</em>. Typhi) efflux pump activity was measured by ethidium bromide (EtBr) cartwheel and semi-automated fluorometry methods respectively. Fluorescence intensity in bacterial colonies was measured under different treatment conditions (with or without drugs) on Muller Hinton agar (MHA) plates containing EtBr in cartwheel assay. EtBr efflux assay was determined following the loading of bacteria with EtBr and fluorescence was recorded over fixed time period with the help of fluorescent spectrophotometer. The results obtained were compared with the control.</p><p><strong>Results: </strong>Efflux pump inhibitor (EPIs) activity of paclitaxel and vinblastine determined by EtBr cartwheel assay registered no activity whereas semi-automated fluorescent assay revealed marginal activity when compared to control.</p><p><strong>Conclusion: </strong>We report the conflicting result of <em>in silico</em> and <em>in vitro</em> studies in predicting the antimicrobial effect of mainstream anticancer drugs as efflux pump inhibitors for <em>Salmonella</em> Typhi.</p>

scholarly journals Effect of α-Bisabolol and Its β-Cyclodextrin Complex as TetK and NorA Efflux Pump Inhibitors in Staphylococcus aureus Strains

Antibiotics ◽  
2020 ◽  
Vol 9 (1) ◽  
pp. 28 ◽  
Author(s):  
Rafael Pereira da Cruz ◽  
Thiago Sampaio de Freitas ◽  
Maria do Socorro Costa ◽  
Antonia Thassya Lucas dos Santos ◽  
Fábia Ferreira Campina ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Inhibitory Concentration ◽  
Efflux Pump ◽  
Physicochemical Characteristics ◽  
Host Molecule ◽  
Cyclodextrin Complex ◽  
Efflux Pump Inhibitor ◽  
Extracellular Medium ◽  
Promising Alternative ◽  
Efflux Pump Inhibitors

Efflux pumps are proteins present in the plasma membrane of bacteria, which transport antibiotics and other compounds into the extracellular medium, conferring resistance. The discovery of natural efflux pump inhibitors is a promising alternative. α-Bisabolol is a sesquiterpene isolated from several plants such as Matricaria chamomilla L. and has important properties such as antibacterial and anti-inflammatory activity. Currently, the formation of inclusion complexes with β-Cyclodextrin has been used for improving the physicochemical characteristics of the host molecule. This study evaluated the effect of α-Bisabolol, in isolation and in complexation with β-Cyclodextrin, as TetK and NorA efflux pump inhibitors in Staphylococcus aureus strains. The minimum inhibitory concentration (MIC) was determined. Subsequently, inhibitory activity over the pumps was observed by an MIC reduction for the antibiotics, by using subinhibitory concentrations (MIC/8) in combination with tetracycline and norfloxacin. The MIC of the compounds was ≥1024 μg/mL. α-Bisabolol potentiated the action of tetracycline and reduced the MIC of norfloxacin to a clinically relevant concentration. The complexed substance showed synergism however, the effect of the isolated α-Bisabolol was superior to the complex. These results indicate α-Bisabolol is a potential substance to be used as an efflux pump inhibitor.

scholarly journals Pseudomonas aeruginosa mexR and mexEF Antibiotic Efflux Pump Variants Exhibit Increased Virulence

Antibiotics ◽  
2021 ◽  
Vol 10 (10) ◽  
pp. 1164
Author(s):  
Mylene Vaillancourt ◽  
Sam P. Limsuwannarot ◽  
Catherine Bresee ◽  
Rahgavi Poopalarajah ◽  
Peter Jorth
Keyword(s):  
Gene Expression ◽  
Pseudomonas Aeruginosa ◽  
Efflux Pump ◽  
Infection Model ◽  
Dependent Manner ◽  
Resistance Mutations ◽  
Efflux Pump Inhibitor ◽  
Pump System ◽  
Mouse Infection Model ◽  
Epithelial Barriers

Antibiotic-resistant Pseudomonas aeruginosa infections are the primary cause of mortality in people with cystic fibrosis (CF). Yet, it has only recently become appreciated that resistance mutations can also increase P. aeruginosa virulence, even in the absence of antibiotics. Moreover, the mechanisms by which resistance mutations increase virulence are poorly understood. In this study we tested the hypothesis that mutations affecting efflux pumps can directly increase P. aeruginosa virulence. Using genetics, physiological assays, and model infections, we show that efflux pump mutations can increase virulence. Mutations of the mexEF efflux pump system increased swarming, rhamnolipid production, and lethality in a mouse infection model, while mutations in mexR that increased expression of the mexAB-oprM efflux system increased virulence during an acute murine lung infection without affecting swarming or rhamnolipid gene expression. Finally, we show that an efflux pump inhibitor, which represents a proposed novel treatment approach for P. aeruginosa, increased rhamnolipid gene expression in a dose-dependent manner. This finding is important because rhamnolipids are key virulence factors involved in dissemination through epithelial barriers and cause neutrophil necrosis. Together, these data show how current and proposed future anti-Pseudomonal treatments may unintentionally make infections worse by increasing virulence. Therefore, treatments that target efflux should be pursued with caution.

scholarly journals An Efflux Pumps Inhibitor Significantly Improved the Antibacterial Activity of Botanicals from Plectranthus glandulosus towards MDR Phenotypes

2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Gravalain Nanmeni ◽  
Alex T. Tedonkeu ◽  
Aimé G. Fankam ◽  
Armelle T. Mbaveng ◽  
Brice E. N. Wamba ◽  
...  
Keyword(s):  
Antibacterial Activity ◽  
Efflux Pump ◽  
Ethanol Extract ◽  
Efflux Pumps ◽  
Multidrug Resistant ◽  
Spectroscopic Techniques ◽  
Efflux Pump Inhibitor ◽  
Phytochemical Study ◽  
Microdilution Method ◽  
Broth Microdilution Method

Bacterial multidrug resistance causes many therapeutic failures, making it more difficult to fight against bacterial diseases. This study aimed to investigate the antibacterial activity of extract, fractions, and phytochemicals from Plectranthus glandulosus (Lamiaceae) against multidrug-resistant (MDR) Gram-negative phenotypes expressing efflux pumps. The crude extract after extraction was subjected to column chromatography, and the structures of the isolated compounds were determined using spectrometric and spectroscopic techniques. Antibacterial assays of samples alone and in the presence of an efflux pump inhibitor (phenylalanine-arginine β-naphthylamide, PAβN) were carried out using the broth microdilution method. The phytochemical study of P. glandulosus plant extract afforded seven major fractions (A–G) which lead to the isolation of seventeen known compounds. The ethanol extract of P. glandulosus was not active at up to 1024 μg/mL, whereas its fractions showed MICs varying from 32 to 512 μg/mL on the studied bacteria. Fraction C of P. glandulosus showed the lowest MIC (32 μg/mL) on E. coli ATCC8739 strain. Fraction D presented the highest activity spectrum by inhibiting the growth of 90% (9/10) of the studied bacteria. The presence of PAβN has improved the activity of extract and all fractions. Overall, the tested phytochemicals showed low activity against the studied bacteria. The overall results obtained in this study show that some fractions from P. glandulosus, mainly fractions C and D, should be investigated more for their possible use to fight against MDR bacteria.

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