scholarly journals A Study the Effect of TiO2 Nanoparticles Combination with Antibiotics and Plant extracts Against Some Gram Negative Bacteria

2016 ◽  
Vol 13 (3) ◽  
pp. 425-434
Author(s):  
Baghdad Science Journal
Keyword(s):  
Titanium Dioxide ◽  
Acinetobacter Baumannii ◽  
Tio2 Nanoparticles ◽  
Plant Extracts ◽  
Salvia Officinalis ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
E Coli ◽  
Origanum Majorana ◽  
Arctium Minus

Titanium dioxide TiO2 has been widely utilized in cleaning and sterilizing material for many clinical tools sanitary ware, food tableware and cooking and items for use in hospitals. Titanium dioxide TiO2 non toxicity and long term physical and chemical stability. It has been widely used decomposition of organic compounds and microbial organisms such as cancer cell, viruses and bacteria as well as its potential application in sterilization of medical devices. The aim of the study the effect of titanium dioxide TiO2 on some Gram negative bacteria and study their effects on some virulence factors and chromosomal DNA.In this study, we obtained (E. coli ? Proteus mirabilis, Proteus vulgaris ? Pseudomonas aeruginosa ? Klebsiella pneumonia and Acinetobacter baumannii) from Al-Emamain Al-Kadhemain Medical City Hospital in Baghdad. Samples collection were carried out from 1 April to 30 June 2014. Study the effect of (plant extraction and Antibiotic) alone and combination with Titanium dioxide TiO2 on bacteria growth. And study the effect of Titanium dioxide TiO2 on biofilm layer and chromosomal DNA.Combinations of TiO2 nanoparticle with water and alcohol extracts of plant (Salvia officinalis ?Arctium minus, Origanum majorana and Anabasis syriaca) gave synergistic results against the gram negative bacterial isolates.A Synergism effect was observed in combination of Ciprofloxacin with Titanium TiO2 nanoparticles toward all Gram negative bacteria. Also a high efficiency was observed when TiO2 nanoparticles mixed with Amikacin toward all isolates except Acinetobacter baumannii and E. coli3. While the results of mixing TiO2 nanoparticles with Cephalothin indicate highly efficiency toward all isolates except Pseudomonas aeruginosa.The combination of plant extracts (Salvia officinalis ? Arctium minus ? Origanum majorana and Anabasis syriaca) with TiO2 nanoparticles was appear to be damaged to E. coli chromosomal DNA.The study showed the ability of nanoparticles TiO2 to inhibition of the layer Biofilm to all isolates of bacteria at concentrations (1, 1.5) µg/ ml.Conclude from this study we can be used TiO2 nanoparticles to kill some types of bacteria

scholarly journals Fluorescence High-Throughput Screening for Inhibitors of TonB Action

2017 ◽  
Vol 199 (10) ◽  
Author(s):  
Brittany L. Nairn ◽  
Olivia S. Eliasson ◽  
Dallas R. Hyder ◽  
Noah J. Long ◽  
Aritri Majumdar ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Acinetobacter Baumannii ◽  
High Throughput ◽  
High Throughput Screening ◽  
Resistant Bacteria ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
Content Type ◽  
E Coli ◽  
Compound Libraries

ABSTRACT Gram-negative bacteria acquire ferric siderophores through TonB-dependent outer membrane transporters (TBDT). By fluorescence spectroscopic hgh-throughput screening (FLHTS), we identified inhibitors of TonB-dependent ferric enterobactin (FeEnt) uptake through Escherichia coli FepA (EcoFepA). Among 165 inhibitors found in a primary screen of 17,441 compounds, we evaluated 20 in secondary tests: TonB-dependent ferric siderophore uptake and colicin killing and proton motive force-dependent lactose transport. Six of 20 primary hits inhibited TonB-dependent activity in all tests. Comparison of their effects on [59Fe]Ent and [14C]lactose accumulation suggested several as proton ionophores, but two chemicals, ebselen and ST0082990, are likely not proton ionophores and may inhibit TonB-ExbBD. The facility of FLHTS against E. coli led us to adapt it to Acinetobacter baumannii. We identified its FepA ortholog (AbaFepA), deleted and cloned its structural gene, genetically engineered 8 Cys substitutions in its surface loops, labeled them with fluorescein, and made fluorescence spectroscopic observations of FeEnt uptake in A. baumannii. Several Cys substitutions in AbaFepA (S279C, T562C, and S665C) were readily fluoresceinated and then suitable as sensors of FeEnt transport. As in E. coli, the test monitored TonB-dependent FeEnt uptake by AbaFepA. In microtiter format with A. baumannii, FLHTS produced Z′ factors 0.6 to 0.8. These data validated the FLHTS strategy against even distantly related Gram-negative bacterial pathogens. Overall, it discovered agents that block TonB-dependent transport and showed the potential to find compounds that act against Gram-negative CRE (carbapenem-resistant Enterobacteriaceae)/ESKAPE (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter species) pathogens. Our results suggest that hundreds of such chemicals may exist in larger compound libraries. IMPORTANCE Antibiotic resistance in Gram-negative bacteria has spurred efforts to find novel compounds against new targets. The CRE/ESKAPE pathogens are resistant bacteria that include Acinetobacter baumannii, a common cause of ventilator-associated pneumonia and sepsis. We performed fluorescence high-throughput screening (FLHTS) against Escherichia coli to find inhibitors of TonB-dependent iron transport, tested them against A. baumannii, and then adapted the FLHTS technology to allow direct screening against A. baumannii. This methodology is expandable to other drug-resistant Gram-negative pathogens. Compounds that block TonB action may interfere with iron acquisition from eukaryotic hosts and thereby constitute bacteriostatic antibiotics that prevent microbial colonization of human and animals. The FLHTS method may identify both species-specific and broad-spectrum agents against Gram-negative bacteria.

scholarly journals Comparison of clinical characteristics and outcomes of bloodstream infections due to multidrug-resistant Acinetobacter baumannii and other Gram-negative bacteria in ICU patients

2020 ◽  
Author(s):  
Ying Qian ◽  
Yongpeng Xie ◽  
Haifeng Mao ◽  
Jiguang Li ◽  
Caihong Gu ◽  
...  
Keyword(s):  
Septic Shock ◽  
Drug Resistance ◽  
Acinetobacter Baumannii ◽  
Clinical Characteristics ◽  
Multidrug Resistant ◽  
Resistance Rate ◽  
Apache Ii Score ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
E Coli

Abstract Background: Multidrug-resistant (MDR) bloodstream infection (BSI) by Gram-negative bacteria (GNB) is an important cause of mortality in the intensive care unit (ICU). The purpose of this study was to compare the clinical characteristics of some GNB BSIs and to analyze their drug resistance, with an emphasis on the analysis of prognostic risk factors related to MDR-Acinetobacter baumannii (A. baumannii) BSI.Methods: A retrospective study was conducted in the ICU of lianyungang hospital in China. Patients with BSIs due to MDR-A. baumannii, MDR-Klebsiella pneumoniae (K. pneumoniae), MDR-Pseudomonas aeruginosa (P. aeruginosa) and MDR-Escherichia coli (E. coli) were included.Results: The overall drug resistance rate to imipenem of A. baumannii and K. pneumoniae was significantly higher than that of P. aeruginosa and E. coli (95.8% and 75.5% vs 44.6% and 9.2% respectively). The mortality rates were 71.9%, 63.3%, 41.5% and 38.1%, respectively. The multivariate analysis of MDR-A. baumannii BSI, APACHE II score, hormone use, development of septic shock were associated with the 30-day mortality, while high albumin level with survival.Conclusion: The treatment of MDR-A. baumannii and MDR-K. pneumoniae infection resulted difficult due to their high drug resistance rate. However, the understanding of the clinical characteristics of different BSIs might be helpful to predict, to some extent, the pathogenic bacteria involved so as to proceed with an early sensitive antibiotic treatment. The high mortality rate due to BSI MDR-A. baumannii might be correlated with APACHE II score, nutritional status, and hormone therapy, while septic shock was a warning sign of poor prognosis.

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.

In vitro antibacterial and antibiotic-potentiation activities of five edible plant extracts and mode of action against several MDR Gram-negative phenotypes

2020 ◽  
Vol 4 (1) ◽  
pp. 1-14
Author(s):  
Carine M.N. Ngaffo ◽  
Simplice B. Tankeo ◽  
Michel-Gael F. Guefack ◽  
Brice E. N. Wamba ◽  
Paul Nayim ◽  
...  
Keyword(s):  
Secondary Metabolites ◽  
Bioactive Compounds ◽  
Plant Extracts ◽  
Theobroma Cacao ◽  
Efflux Pumps ◽  
Phoenix Dactylifera ◽  
Food Plants ◽  
Proton Pumps ◽  
Gram Negative ◽  
E Coli

Abstract Background: Bacterial infections involving the multidrug resistant (MDR) strains are among the top leading causes of death throughout the world. Healthcare system across the globe has been suffering from an extra-ordinary burden in terms of looking for the new and more potent antimicrobial compounds. The aim of the present study was to determine the antibacterial activity of some Cameroonian edible plants (Garcinia lucida bark, Phoenix dactylifera pericarps, Theobroma cacao pod, Solanum macrocarpon leaves and Termitomyces titanicus whole plant) and their antibiotics-potentiation effects against some MDR Gram-negative bacteria phenotypes expressing efflux pumps (Escherichia coli, Enterobacter aerogenes, Klebsiella pneumoniae, Pseudomonas aeruginosa and Providencia stuartii strains). Methods: The antibacterial activities of plant extract alone and in combination with usual antibiotics were carried out using the micro-dilution method. The effects of the most active plant extract (Garcinia lucida bark) on H+-ATPase-mediated proton pumps and on bacterial growth kinetic were performed using experimental protocols, while qualitative reference methods were used to highligh the major groups of secondary metabolites present in the extracts. Results: Qualitative phytochemical screening of plant extracts indicated that all analysed secondary metabolites were present in Theobroma cacao and Termitomyces titanicus while one (saponins) of them was absent in Garcinia lucida and Solanum macrocarpon. Only three of them (polyphenols, flavonoids and saponins) were detected in Phoenix dactylifera. Antibacterial essays showed that G. lucida was the most active plant as it inhibited the growth of all studied bacteria with strong activity (MIC<100 µg/mL) against E. coli ATCC8739, significant activity (100≤MIC≤512 µg/mL) against 80% of bacteria and moderate activity (512<MIC≤2048 µg/mL) against E. coli AG100A and E. aerogenes (EA289 and CM64). It was followed by T. cacao and S. macrocarpon extracts which exhibited an antibacterial potential against 95% and 80% of bacterial strains, respectively. These three extracts exhibited a bactericidal effect on a few bacteria. Extracts from T. titanicus and P. dactylifera were less active as they moderately (512<MIC≤2048 µg/mL) inhibited the growth of 35% and 10% of bacteria. All extracts selectively potentiated the activities of all antibiotics with improvement activity factors (IAF) ranging from 2 to 256. G. lucida, T. cacao and S. macrocarpon potentiated the activities of 100%, 89% and 67% of antibiotics respectively against more than 70%, suggesting that they contain bioactive compounds which could be considered as efflux pumps inhibitors. Whereas T. titanicus and P. dactylifera improved the activities of almost 40% and 20% of antibiotics, respectively. This increase of activities also characterizes synergistic effects between antibiotics and these bioactive compounds. G. lucida extract at all tested concentrations, strongly inhibited the growth of bacterial strain E. coli ATCC8739 and exhibited an inhibitory effect on this bacterial H+-ATPase-mediated proton pumps increasing the pH of the medium. Conclusion: The overall results indicated that food plants among which G. lucida, T. cacao and S. macrocarpon could have a benefit interest in combatting resistant types of bacteria. Keywords: Food plants; infectious diseases; MDR bacteria; efflux pumps; antibiotics; secondary metabolites.

Structure-Activity Relationship and Antimicrobial Evaluation of N-Phenylpyrazole Curcumin Derivatives

2020 ◽  
Vol 16 (4) ◽  
pp. 481-488
Author(s):  
Heli Sanghvi ◽  
Satyendra Mishra
Keyword(s):  
Antibacterial Activity ◽  
Gram Negative Bacteria ◽  
Pyrazole Derivatives ◽  
Gram Positive ◽  
Gram Negative ◽  
E Coli ◽  
Curcumin Derivatives ◽  
Structure Activity ◽  
Electron Donating Groups ◽  
Derivatives Of

Background: Curcumin, one of the most important pharmacologically significant natural products, has gained significant consideration among scientists for decades since its multipharmacological activities. 1, 3-Dicarbonyl moiety of curcumin was found to be accountable for the rapid degradation of curcumin molecule. The aim of present work is to replace 1, 3-dicarbonyl moiety of curcumin by pyrazole and phenylpyrazole derivatives with a view to improving its stability and to investigate the role of substitution in N-phenylpyrazole curcumin on its antibacterial activity against both Gram-positive as well as Gram-negative bacteria. Methods: Pyrazole derivatives of curcumin were prepared by heating curcumin with phenyhydrazine/ substituted phenyhydrazine derivatives in AcOH. The residue was purified by silica gel column chromatography. Structures of purified compounds were confirmed by 1H NMR and Mass spectroscopy. The synthesized compounds were evaluated for their antibacterial activity by the microdilution broth susceptibility test method against gram positive (S. aureus) and gram negative (E. coli). Results: Effects of substitution in N-phenylpyrazole curcumin derivatives against S. aureus and E. coli were studied. The most active N-(3-Nitrophenylpyrazole) curcumin (12) exhibits twenty-fold more potency against S. aureus (MIC: 10μg/mL)) and N-(2-Fluoroophenylpyrazole) curcumin (5) fivefold more potency against E. coli (MIC; 50 μg/mL) than N-phenylpyrazole curcumin (4). Whereas, a remarkable decline in anti-bacterial activity against S. aureus and E. coli was observed when electron donating groups were incorporated in N-phenylpyrazole curcumin (4). Comparative studies of synthesized compounds suggest the effects of electron withdrawing and electron donating groups on unsubstituted phenylpyrazole curcumin (4). Conclusion: The structure-activity relationship (SAR) results indicated that the electron withdrawing and electron donating at N-phenylpyrazole curcumin played key roles for their bacterial inhibitory effects. The results of the antibacterial evaluation showed that the synthesized pyrazole derivatives of curcumin displayed moderate to very high activity in S. aureus. In conclusion, the series of novel curcumin derivatives were designed, synthesized and tested for their antibacterial activities against S. aureus and E. coli. Among them, N-(3-Nitrophenylpyrazole curcumin; 12) was most active against S. aureus (Gram-positive) and N-(2-Fluoroophenylpyrazole) curcumin (5) against E. coli (Gram-negative) bacteria.

Quality Improvement of the DNA extracted by boiling method in Gram negative bacteria

2017 ◽  
Vol 6 (04) ◽  
pp. 5347 ◽  
Author(s):  
Omar B. Ahmed* ◽  
Anas S. Dablool
Keyword(s):  
Dna Extraction ◽  
Control Method ◽  
Extraction Procedure ◽  
Cost Effective ◽  
High Yield ◽  
Gram Negative Bacteria ◽  
Bacterial Dna ◽  
Gram Negative ◽  
E Coli

Several methods of Deoxyribonucleic acid (DNA) extraction have been applied to extract bacterial DNA. The amount and the quality of the DNA obtained for each one of those methods are variable. The study aimed to evaluate bacterial DNA extraction using conventional boiling method followed by alcohol precipitation. DNA extraction from Gram negative bacilli was extracted and precipitated using boiling method with further precipitation by ethanol. The extraction procedure performed using the boiling method resulted in high DNA yields for both E. coli and K. pneumoniae bacteria in (199.7 and 285.7μg/ml, respectively) which was close to control method (229.3 and 440.3μg/ml). It was concluded that after alcohol precipitation boiling procedure was easy, cost-effective, and applicable for high-yield quality of DNA in Gram-negative bacteria.

scholarly journals Clonal Clusters, Molecular Resistance Mechanisms and Virulence Factors of Gram-Negative Bacteria Isolated from Chronic Wounds in Ghana

Antibiotics ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 339
Author(s):  
Denise Dekker ◽  
Frederik Pankok ◽  
Thorsten Thye ◽  
Stefan Taudien ◽  
Kwabena Oppong ◽  
...  
Keyword(s):  
Molecular Epidemiology ◽  
Virulence Factors ◽  
Iron Uptake ◽  
Chronic Wounds ◽  
Sub Saharan Africa ◽  
Gram Negative Bacteria ◽  
Beta Lactamase ◽  
Secretion Systems ◽  
Gram Negative ◽  
E Coli

Wound infections are common medical problems in sub-Saharan Africa but data on the molecular epidemiology are rare. Within this study we assessed the clonal lineages, resistance genes and virulence factors of Gram-negative bacteria isolated from Ghanaian patients with chronic wounds. From a previous study, 49 Pseudomonas aeruginosa, 21 Klebsiellapneumoniae complex members and 12 Escherichia coli were subjected to whole genome sequencing. Sequence analysis indicated high clonal diversity with only nine P. aeruginosa clusters comprising two strains each and one E. coli cluster comprising three strains with high phylogenetic relationship suggesting nosocomial transmission. Acquired beta-lactamase genes were observed in some isolates next to a broad spectrum of additional genetic resistance determinants. Phenotypical expression of extended-spectrum beta-lactamase activity in the Enterobacterales was associated with blaCTX-M-15 genes, which are frequent in Ghana. Frequently recorded virulence genes comprised genes related to invasion and iron-uptake in E. coli, genes related to adherence, iron-uptake, secretion systems and antiphagocytosis in P. aeruginosa and genes related to adherence, biofilm formation, immune evasion, iron-uptake and secretion systems in K. pneumonia complex. In summary, the study provides a piece in the puzzle of the molecular epidemiology of Gram-negative bacteria in chronic wounds in rural Ghana.

scholarly journals Apomorphine Targets the Pleiotropic Bacterial Regulator Hfq

Antibiotics ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 257
Author(s):  
Florian Turbant ◽  
David Partouche ◽  
Omar El Hamoui ◽  
Sylvain Trépout ◽  
Théa Legoubey ◽  
...  
Keyword(s):  
Small Rnas ◽  
Antibacterial Agents ◽  
Amyloid Fibrils ◽  
Noncoding Rnas ◽  
Amyloid Formation ◽  
Gram Negative Bacteria ◽  
Translation Efficiency ◽  
Gram Negative ◽  
Bacterial Adaptation ◽  
E Coli

Hfq is a bacterial regulator with key roles in gene expression. The protein notably regulates translation efficiency and RNA decay in Gram-negative bacteria, thanks to its binding to small regulatory noncoding RNAs. This property is of primary importance for bacterial adaptation and survival in hosts. Small RNAs and Hfq are, for instance, involved in the response to antibiotics. Previous work has shown that the E. coli Hfq C-terminal region (Hfq-CTR) self-assembles into an amyloid structure. It was also demonstrated that the green tea compound EpiGallo Catechin Gallate (EGCG) binds to Hfq-CTR amyloid fibrils and remodels them into nonamyloid structures. Thus, compounds that target the amyloid region of Hfq may be used as antibacterial agents. Here, we show that another compound that inhibits amyloid formation, apomorphine, may also serve as a new antibacterial. Our results provide an alternative in order to repurpose apomorphine, commonly used in the treatment of Parkinson’s disease, as an antibiotic to block bacterial adaptation to treat infections.

scholarly journals Proteomic response of Escherichia coli to a membrane lytic and iron chelating truncated Amaranthus tricolor defensin

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Tessa B. Moyer ◽  
Ashleigh L. Purvis ◽  
Andrew J. Wommack ◽  
Leslie M. Hicks
Keyword(s):  
Escherichia Coli ◽  
Antibacterial Activity ◽  
Antimicrobial Peptides ◽  
Mechanism Of Action ◽  
Gram Negative Bacteria ◽  
Amaranthus Tricolor ◽  
Core Motif ◽  
Gram Negative ◽  
E Coli ◽  
Membrane Lysis

Abstract Background Plant defensins are a broadly distributed family of antimicrobial peptides which have been primarily studied for agriculturally relevant antifungal activity. Recent studies have probed defensins against Gram-negative bacteria revealing evidence for multiple mechanisms of action including membrane lysis and ribosomal inhibition. Herein, a truncated synthetic analog containing the γ-core motif of Amaranthus tricolor DEF2 (Atr-DEF2) reveals Gram-negative antibacterial activity and its mechanism of action is probed via proteomics, outer membrane permeability studies, and iron reduction/chelation assays. Results Atr-DEF2(G39-C54) demonstrated activity against two Gram-negative human bacterial pathogens, Escherichia coli and Klebsiella pneumoniae. Quantitative proteomics revealed changes in the E. coli proteome in response to treatment of sub-lethal concentrations of the truncated defensin, including bacterial outer membrane (OM) and iron acquisition/processing related proteins. Modification of OM charge is a common response of Gram-negative bacteria to membrane lytic antimicrobial peptides (AMPs) to reduce electrostatic interactions, and this mechanism of action was confirmed for Atr-DEF2(G39-C54) via an N-phenylnaphthalen-1-amine uptake assay. Additionally, in vitro assays confirmed the capacity of Atr-DEF2(G39-C54) to reduce Fe3+ and chelate Fe2+ at cell culture relevant concentrations, thus limiting the availability of essential enzymatic cofactors. Conclusions This study highlights the utility of plant defensin γ-core motif synthetic analogs for characterization of novel defensin activity. Proteomic changes in E. coli after treatment with Atr-DEF2(G39-C54) supported the hypothesis that membrane lysis is an important component of γ-core motif mediated antibacterial activity but also emphasized that other properties, such as metal sequestration, may contribute to a multifaceted mechanism of action.

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