scholarly journals Thymol tolerance in Escherichia coli induces morphological, metabolic and genetic changes

2019 ◽  
Vol 19 (1) ◽  
Author(s):  
Fatemah Al-Kandari ◽  
Rabeah Al-Temaimi ◽  
Arnoud H. M. van Vliet ◽  
Martin J. Woodward
Keyword(s):  
Antimicrobial Activity ◽  
Efflux Pump ◽  
Wide Spectrum ◽  
Genetic Changes ◽  
E Coli ◽  
Nmr Data ◽  
Stop Mutation ◽  
In The Wild ◽  
Cellular Integrity ◽  
Acrab Efflux Pump

Abstract Background Thymol is a phenolic compound used for its wide spectrum antimicrobial activity. There is a limited understanding of the antimicrobial mechanisms underlying thymol activity. To investigate this, E. coli strain JM109 was exposed to thymol at sub-lethal concentrations and after 16 rounds of exposure, isolates with a 2-fold increased minimal inhibitory concentration (MIC) were recovered (JM109-Thyr). The phenotype was stable after multiple sub-cultures without thymol. Results Cell morphology studies by scanning electron microscopy (SEM) suggest that thymol renders bacterial cell membranes permeable and disrupts cellular integrity. 1H Nuclear magnetic resonance (NMR) data showed an increase in lactate and the lactic acid family amino acids in the wild type and JM109-Thyr in the presence of thymol, indicating a shift from aerobic respiration to fermentation. Sequencing of JM109-Thyr defined multiple mutations including a stop mutation in the acrR gene resulting in a truncation of the repressor of the AcrAB efflux pump. AcrAB is a multiprotein complex traversing the cytoplasmic and outer membrane, and is involved in antibiotic clearance. Conclusions Our data suggests that thymol tolerance in E. coli induces morphological, metabolic and genetic changes to adapt to thymol antimicrobial activity.

scholarly journals Characterization of a Novel Pyranopyridine Inhibitor of the AcrAB Efflux Pump of Escherichia coli

2013 ◽  
Vol 58 (2) ◽  
pp. 722-733 ◽  
Author(s):  
Timothy J. Opperman ◽  
Steven M. Kwasny ◽  
Hong-Suk Kim ◽  
Son T. Nguyen ◽  
Chad Houseweart ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Efflux Pump ◽  
Efflux Pumps ◽  
Gram Negative ◽  
Content Type ◽  
E Coli ◽  
Resistance Nodulation Division ◽  
Rnd Efflux Pumps ◽  
Acrab Efflux Pump

ABSTRACTMembers of the resistance-nodulation-division (RND) family of efflux pumps, such as AcrAB-TolC ofEscherichia coli, play major roles in multidrug resistance (MDR) in Gram-negative bacteria. A strategy for combating MDR is to develop efflux pump inhibitors (EPIs) for use in combination with an antibacterial agent. Here, we describe MBX2319, a novel pyranopyridine EPI with potent activity against RND efflux pumps of theEnterobacteriaceae. MBX2319 decreased the MICs of ciprofloxacin (CIP), levofloxacin, and piperacillin versusE. coliAB1157 by 2-, 4-, and 8-fold, respectively, but did not exhibit antibacterial activity alone and was not active against AcrAB-TolC-deficient strains. MBX2319 (3.13 μM) in combination with 0.016 μg/ml CIP (minimally bactericidal) decreased the viability (CFU/ml) ofE. coliAB1157 by 10,000-fold after 4 h of exposure, in comparison with 0.016 μg/ml CIP alone. In contrast, phenyl-arginine-β-naphthylamide (PAβN), a known EPI, did not increase the bactericidal activity of 0.016 μg/ml CIP at concentrations as high as 100 μM. MBX2319 increased intracellular accumulation of the fluorescent dye Hoechst 33342 in wild-type but not AcrAB-TolC-deficient strains and did not perturb the transmembrane proton gradient. MBX2319 was broadly active againstEnterobacteriaceaespecies andPseudomonas aeruginosa. MBX2319 is a potent EPI with possible utility as an adjunctive therapeutic agent for the treatment of infections caused by Gram-negative pathogens.

scholarly journals Isolation and Antimicrobial Activity of β-Sitosterol-3-O-Glucoside from Lannea Kerstingii Engl. & K. Krause (Anacardiacea)

2016 ◽  
Vol 06 (01) ◽  
pp. 004-008
Author(s):  
Njinga N. S. ◽  
Sule M. I. ◽  
Pateh U. U. ◽  
Hassan H. S. ◽  
Abdullahi S. T. ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Wide Spectrum ◽  
Diffusion Method ◽  
Dilution Method ◽  
Minimum Fungicidal Concentration ◽  
E Coli ◽  
H Nmr ◽  
Vacuum Liquid Chromatography ◽  
Broth Dilution ◽  
C Nmr

AbstractThe emergence of more and more drug resistance bacteria has led to the study of the antimicrobial activity of the compound isolated from Lannea kerstingii Engl. & K. Krause (Anacardiacea) since the active principles of many drugs found in plants are secondary metabolites. A compound was isolated using dry vacuum liquid chromatography and eluting with CHCl3 -EtOAc and monitored using TLC. 3 1 13 The glycoside was characterized using 1 H NMR and 13 C NMR spectra recorded in DMSO-d6 at 400 MHz and 125 MHz, respectively. The antimicrobial activity of the compound was determined using agar diffusion method. The minimum inhibitory concentration (MIC) and minimum bactericidal/minimum fungicidal concentration (MBC/MFC) was determined using broth dilution method. The compound isolated was found to be β-sitosterol-3-O-glucoside. The β-sitosterol-3-O-glucoside (200μg/ml) was active against S. aureus, Methicillin Resistant Staphylococcus aureus, P. mirabilis, S. typhi, K. pneumoniae, E. coli, B. subtilis with zone of inhibition ranging from 24mm to 34mm and inactive against P. aeroginosa and Proteus vulgaris. It was also active against the fungi C. albicans and C. tropicalis but inactive against C. krusei. The MIC ranged from 25 to 50 μg/ml while the MBC/MFC ranged from 50 to 200 μg/ml. These results show the wide spectrum antimicrobial activity of β-sitosterol-3-O-glucoside.

scholarly journals Involvement of Antibiotic Efflux Machinery in Glutathione-Mediated Decreased Ciprofloxacin Activity in Escherichia coli

2016 ◽  
Vol 60 (7) ◽  
pp. 4369-4374 ◽  
Author(s):  
Manish Goswami ◽  
Mahesh Subramanian ◽  
Ranjeet Kumar ◽  
Jana Jass ◽  
Narendra Jawali
Keyword(s):  
Escherichia Coli ◽  
Efflux Pump ◽  
Antibacterial Action ◽  
Potential Mechanism ◽  
Content Type ◽  
Active Efflux ◽  
E Coli ◽  
Acrab Efflux Pump ◽  
Antibiotic Efflux

ABSTRACTWe have analyzed the contribution of different efflux components to glutathione-mediated abrogation of ciprofloxacin's activity inEscherichia coliand the underlying potential mechanism(s) behind this phenomenon. The results indicated that glutathione increased the total active efflux, thereby partially contributing to glutathione-mediated neutralization of ciprofloxacin's antibacterial action inE. coli. However, the role of glutathione-mediated increased efflux becomes evident in the absence of a functional TolC-AcrAB efflux pump.

Molecular mechanisms of antimicrobial resistance in fecal Escherichia coli of healthy dogs after enrofloxacin or amoxicillin administration

2012 ◽  
Vol 58 (11) ◽  
pp. 1288-1294 ◽  
Author(s):  
Sherine A. Aly ◽  
Nipattra Debavalya ◽  
Sang-Jin Suh ◽  
Omar A. Oryazabal ◽  
Dawn M. Boothe
Keyword(s):  
Escherichia Coli ◽  
Antimicrobial Resistance ◽  
Molecular Mechanisms ◽  
Efflux Pump ◽  
Single Mutation ◽  
Topoisomerase Iv ◽  
E Coli ◽  
Genetic Mechanisms ◽  
Healthy Dogs ◽  
Acrab Efflux Pump

Escherichia coli respond to selective pressure of antimicrobial therapy by developing resistance through a variety of mechanisms. The purpose of this study was to characterize the genetic mechanisms of antimicrobial resistance in fecal E. coli after the routine use of 2 popular antimicrobials. Fourteen resistant E. coli isolates, representing predominant clones that emerged in healthy dogs’ feces after treatment with either amoxicillin (11 E. coli isolates) or enrofloxacin (3 E. coli isolates), were tested for mutations in DNA gyrase (gyrA and gyrB) and in topoisomerase IV (parC) and for the presence of β-lactamases (blaTEM, blaSHV, blaPSE-1 and blaCTX-M) and plasmid-mediated quinolone resistance (qnrA, qnrB, qnrS, aac(6′)-Ib, and qepA), by polymerase chain reaction. Escherichia coli isolates cultured following amoxicillin therapy only expressed single-drug resistance to β-lactams, while the isolates cultured from dogs receiving enrofloxacin therapy expressed multidrug resistance (MDR). The use of RND efflux pump inhibitors increased the susceptibility of the 3 MDR E. coli isolates to doxycycline, chloramphenicol, enrofloxacin, and ciprofloxacin, which indicates a role of the efflux pump in the acquisition of the MDR phenotype. Amplification and sequencing of AcrAB efflux pump regulators (soxR, soxS, marR, and acrR) revealed only the presence of a single mutation in soxS in the 3 MDR isolates.

scholarly journals UDP-N-Acetylmuramic Acid l-Alanine Ligase (MurC) Inhibition in atolCMutant Escherichia coli Strain Leads to Cell Death

2014 ◽  
Vol 58 (10) ◽  
pp. 6165-6171 ◽  
Author(s):  
Vaishali Humnabadkar ◽  
K. R. Prabhakar ◽  
Ashwini Narayan ◽  
Sreevalli Sharma ◽  
Supreeth Guptha ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Efflux Pump ◽  
Coli Strain ◽  
Cellular Activity ◽  
Wild Type ◽  
Compound A ◽  
Content Type ◽  
E Coli ◽  
In The Wild ◽  
High Concentrations

ABSTRACTThe Mur ligases play an essential role in the biosynthesis of bacterial peptidoglycan and hence are attractive antibacterial targets. A screen of the AstraZeneca compound library led to the identification of compound A, a pyrazolopyrimidine, as a potent inhibitor ofEscherichia coliandPseudomonas aeruginosaMurC. However, cellular activity againstE. coliorP. aeruginosawas not observed. Compound A was active against efflux pump mutants of both strains. Experiments using anE. colitolCmutant revealed accumulation of the MurC substrate and a decrease in the level of product upon treatment with compound A,indicating inhibition of MurC enzyme in these cells. Such a modulation was not observed in theE. coliwild-type cells. Further, overexpression of MurC in theE. colitolCmutant led to an increase in the compound A MIC by ≥16-fold, establishing a correlation between MurC inhibition and cellular activity. In addition, estimation of the intracellular compound A level showed an accumulation of the compound over time in thetolCmutant strain. A significant compound A level was not detected in the wild-typeE. colistrain even upon treatment with high concentrations of the compound. Therefore, the lack of MIC and absence of MurC inhibition in wild-typeE. coliwere possibly due to suboptimal compound concentration as a consequence of a high efflux level and/or poor permeativity of compound A.

Antimicrobial activity of Romanian propolis ethanolic extracts against E. coli isolated from bovine mastitis

Planta Medica ◽  
2013 ◽  
Vol 79 (13) ◽  
Author(s):  
M Niculae ◽  
CD Sandru ◽  
E Pall ◽  
S Popescu ◽  
L Stan ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Bovine Mastitis ◽  
E Coli ◽  
Ethanolic Extracts

SYNTHESIS, CHARACTERIZATION AND BIOLOGICAL EVALUATION OF 3-FORMYL INDOLE BASED SCHIFF BASES

2018 ◽  
Vol 7 (6) ◽  
Author(s):  
Singh Gurvinder ◽  
Singh Prabhsimran ◽  
Dhawan R. K.
Keyword(s):  
Antimicrobial Activity ◽  
Spectral Analysis ◽  
Schiff Bases ◽  
Antimicrobial Agents ◽  
Biological Evaluation ◽  
Fungal Strain ◽  
Bacterial Strains ◽  
Standard Drug ◽  
Gram Negative ◽  
E Coli

In order to develop new antimicrobial agents, a series of 3-formyl indole based Schiff bases were synthesized by reacting 3-formyl indole(indole-3-carboxaldehyde) with substituted aniline taking ethanol as solvent. The reaction was carried in the presence of small amount of p-toluene sulphonic acid as catalyst.All the synthesized compounds were characterized by IR, 1H-NMR spectral analysis. All the synthesized compounds were evaluated for antimicrobial activity against two gram positive bacterial strains (B. subtilisand S. aureus) and two gram negative bacterial strains (P. aeruginosaand E. coli) and one fungal strain (C. albicans). All the synthesized compounds were found to have moderate to good antimicrobial activity. The  standard drug amoxicillin, fluconazole were used for antimicrobial activity. Among the synthesized compounds, the maximum antimicrobial activity was shown by compounds GS04, GS07, GS08 and GS10.

Disinfection of Fruits with Activated Water

2019 ◽  
Vol 10 ◽  
pp. 1864-1872
Author(s):  
Prof. Teodora P. Popova
Keyword(s):  
Antimicrobial Activity ◽  
Aqueous Solutions ◽  
Antimicrobial Properties ◽  
The Other ◽  
Gram Negative Bacteria ◽  
High Antimicrobial Activity ◽  
Gram Negative ◽  
E Coli ◽  
Number Of Microorganisms ◽  
Lower Effect

The effect of ionized aqueous solutions (anolytes and catholyte) in the processing of fruits (cherries, morellos, and strawberries) for decontamination has been tested. Freshly prepared analytes and catholyte without the addition of salts were used, as well as stored for 7 months anolytes, prepared with 0.5% NaCl and a combination of 0.5% NaCl and 0.5% Na2CO3. The anolyte prepared with a combination of 0.5% NaCl and 0.5% Na2CO3, as well as the anolyte obtained with 0.5% NaCl, exhibit high antimicrobial activity against the surface microflora of strawberries, cherries, and sour cherries. They inactivate E. coli for 15 minutes. The other species of the fam. Enterobacteriaceae were also affected to the maximum extent, as is the total number of microorganisms, especially in cherries and sour cherries. Even stored for 7 months, they largely retain their antimicrobial properties. Anolyte and catholyte, obtained without the addition of salts, showed a lower effect on the total number of microorganisms, but had a significant effect on Gram-negative bacteria, and especially with regard to the sanitary indicative E. coli.

Antimicrobial Activity of Silver Nanoparticles Prepared Under an Ultrasonic Field

2011 ◽  
Vol 4 (3) ◽  
pp. 1491-1496
Author(s):  
Umadevi M ◽  
Rani T ◽  
Balakrishnan T ◽  
Ramanibai R
Keyword(s):  
Escherichia Coli ◽  
Antimicrobial Activity ◽  
Silver Nanoparticles ◽  
Reduction Method ◽  
Therapeutic Potential ◽  
Chemical Reduction ◽  
Ultrasonic Field ◽  
Great Promise ◽  
Chemical Reduction Method ◽  
E Coli

Nanotechnology has great promise for improving the therapeutic potential of medicinal molecules and related agents. In this study, silver nanoparticles of different sizes were synthesized in an ultrasonic field using the chemical reduction method with sodium borohydride as a reducing agent. The size effect of silver nanoparticles on antimicrobial activity were tested against the microorganisms Staphylococcus aureus (MTCC No. 96), Bacillus subtilis (MTCC No. 441), Streptococcus mutans (MTCC No. 497), Escherichia coli (MTCC No. 739) and Pseudomonas aeruginosa (MTCC No. 1934). The results shows that B. subtilis, and E. coli were more sensitive to silver nanoparticles and its size, indicating the superior antimicrobial efficacy of silver nanoparticles. 

Antimicrobial Activity of Silver Nanoparticles Synthesized by Streptomyces Species JF714876

2012 ◽  
Vol 5 (1) ◽  
pp. 1638-1642 ◽  
Author(s):  
Vidyasagar G M ◽  
Shankaravva B ◽  
R Begum ◽  
Imrose ◽  
Sagar R ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Silver Nanoparticles ◽  
Silver Ions ◽  
Human Beings ◽  
Streptomyces Species ◽  
Force Microscopy ◽  
E Coli ◽  
Extracellular Synthesis ◽  
Atomic Force ◽  
Uv Visible

Microorganisms like fungi, actinomycetes and bacteria are considered nanofactories and are helpful in the production of nanoparticles useful in the welfare of human beings. In the present study, we investigated the production of silver nanoparticles from Streptomyces species JF714876. Extracellular synthesis of silver nanoparticles by Streptomyces species was carried out using two different media. Silver nanoparticles were examined using UV-visible, IR and atomic force microscopy. The size of silver nanoparticles was in the range of 80-100 nm. Antimicrobial activity of silver nanoparticle against bacteria such as E. coli, S. aureus, and dermatophytes like T. rubrum and T. tonsurans was determined. Thus, this study suggests that the Streptomyces sp. JF741876 can produce silver ions that can be used as an antimicrobial substance.

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