scholarly journals Human Bile Reduces Antimicrobial Activity of Selected Antibiotics against Enterococcus faecalis and Escherichia coliIn Vitro

2017 ◽  
Vol 61 (8) ◽  
Author(s):  
Beatrix Wulkersdorfer ◽  
David Jaros ◽  
Sabine Eberl ◽  
Stefan Poschner ◽  
Walter Jäger ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Enterococcus Faecalis ◽  
Bacterial Infections ◽  
Lung Surfactant ◽  
Strong Impact ◽  
Bacterial Killing ◽  
Human Bile ◽  
Content Type ◽  
E Coli ◽  
Growth Controls

ABSTRACT It has been known from previous studies that body fluids, such as cerebrospinal fluid, lung surfactant, and urine, have a strong impact on the bacterial killing of many anti-infective agents. However, the influence of human bile on the antimicrobial activity of antibiotics is widely unknown. Human bile was obtained and pooled from 11 patients undergoing cholecystectomy. After sterilization of the bile fluid by gamma irradiation, its effect on bacterial killing was investigated for linezolid (LZD) and tigecycline (TGC) against Enterococcus faecalis ATCC 29212. Further, ciprofloxacin (CIP), meropenem (MEM), and TGC were tested against Escherichia coli ATCC 25922. Time-kill curves were performed in pooled human bile and Mueller-Hinton broth (MHB) over 24 h. Bacterial counts (in CFU per milliliter after 24 h) of bile growth controls were approximately equal to MHB growth controls for E. coli and approximately 2-fold greater for E. faecalis, indicating a promotion of bacterial growth by bile for the latter strain. Bile reduced the antimicrobial activity of CIP, MEM, and TGC against E. coli as well as the activity of LZD and TGC against E. faecalis. This effect was strongest for TGC against the two strains. Degradation of TGC in bile was identified as the most likely explanation. These findings may have important implications for the treatment of bacterial infections of the gallbladder and biliary tract and should be explored in more detail.

Phytochemical Extracts of Leucas Aspera and Dahlia Pinnata Exhibit Antimicrobial Properties on Escherichia Coli and Enterococcus Faecalis.

2020 ◽  
Vol 09 ◽  
Author(s):  
Yamuna Saravanan ◽  
Bala Subramaniam Devaraj ◽  
Nithesh Kumar Velusamy ◽  
Pooja Shree Soundirarajan ◽  
Kumaravel Kandaswamy
Keyword(s):  
Escherichia Coli ◽  
Antimicrobial Activity ◽  
Enterococcus Faecalis ◽  
Bacterial Infections ◽  
Aqueous Extracts ◽  
Bacterial Strains ◽  
Efficacy Evaluation ◽  
E Coli ◽  
Methanol Extracts ◽  
Leucas Aspera

Background:: Phytochemicals such as tannins, alkaloids, flavonoids, and peptides been found to have antimicrobial activity against a variety of bacterial strains. Objective:: However, optimal extraction procedures for these phytochemicals and their efficacy evaluation against certain pathogenic bacterial strains remain unclear. Method:: Therefore, in this study phytochemicals from Leucas aspera (L. aspera) and Dahlia pinnata (D. pinnata) were extracted by hot and cold extraction methods using water and methanol as solvents. In addition, antimicrobial activity of L. aspera and D. pinnata extracts against bacterial strains such as the gram-negative Escherichia coli (E. coli) and the gram-positive Enterococcus faecalis (E. faecalis) were performed by Minimal Inhibitory Concentration (MIC) and CFU quantification assays. Results:: The majority of the phytochemicals such as protein, carbohydrate, tannins, flavonoids, phenols, and saponins were present in our extracts but steroids were absent in the extract. Protein, tannins, flavonoids, phenols, and saponins were present in both L. aspera and D. pinnata. The yield of proteins was high (1.990 ± 0.091 mg/ml) in methanol extracts of L. aspera and low (0.199 mg/ml) in aqueous extracts. However, the yield of tannins was high (1.713 ± 0.079 mg/ml) in methanol extracts of D. pinnata and low (0.528 ± 0.136 mg/ml) aqueous extracts. The MIC of D. pinnata extracts were found to be 200 mg/ml for both E. coli and E. faecalis. However the L. aspera extracts had a MIC of 100 mg/ml and 200 mg/ml on E. coli and E. faecalis, respectively. Conclusion:: This article demonstrated the potential use of phytochemicals as novel antimicrobial compounds against bacterial infections.

scholarly journals Antimicrobial Activity of Cationic Poly(3-hexylthiophene) Nanoparticles Coupled with Dual Fluorescent and Electrochemical Sensing: Theragnostic Prospect

Sensors ◽  
2021 ◽  
Vol 21 (5) ◽  
pp. 1715
Author(s):  
Nada Elgiddawy ◽  
Shiwei Ren ◽  
Wadih Ghattas ◽  
Waleed M. A. El Rouby ◽  
Ahmed O. El-Gendy ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Fluorescence Spectroscopy ◽  
Bacterial Infections ◽  
Electrochemical Impedance ◽  
Spectroscopic Properties ◽  
Electrochemical Sensing ◽  
E Coli ◽  
Normal Human ◽  
Dual Detection ◽  
Bacteria And Fungi

Designing therapeutic and sensor materials to diagnose and eliminate bacterial infections remains a significant challenge for active theragnostic nanoprobes. In the present work, fluorescent/electroactive poly(3-hexylthiophene) P3HT nanoparticles (NPs) stabilized with quaternary ammonium salts using cetyltrimethylammonium bromide (CTAB), (CTAB-P3HT NPs) were prepared using a simple mini-emulsion method. The morphology, spectroscopic properties and electronic properties of CTAB-P3HT NPs were characterized by DLS, zeta potential, SEM, TEM, UV-vis spectrophotometry, fluorescence spectroscopy and electrochemical impedance spectroscopy (EIS). In an aqueous solution, CTAB-P3HT NPs were revealed to be uniformly sized, highly fluorescent and present a highly positively charged NP surface with good electroactivity. Dual detection was demonstrated as the binding of the bacteria to NPs could be observed by fluorescence quenching as well as by the changes in EIS. Binding of E. coli to CTAB-P3HT NPs was demonstrated and LODs of 5 CFU/mL and 250 CFU/mL were obtained by relying on the fluorescence spectroscopy and EIS, respectively. The antimicrobial activity of CTAB-P3HT NPs on bacteria and fungi was also studied under dark and nutritive conditions. An MIC and an MBC of 2.5 µg/mL were obtained with E. coli and with S. aureus, and of 0.312 µg/mL with C. albicans. Additionally a good biocompatibility toward normal human cells (WI38) was observed, which opens the way to their possible use as a therapeutic agent.

scholarly journals Therapeutic effects of human mesenchymal stem cell microvesicles in an ex vivo perfused human lung injured with severe E. coli pneumonia

Thorax ◽  
2018 ◽  
Vol 74 (1) ◽  
pp. 43-50 ◽  
Author(s):  
Jeonghyun Park ◽  
Seonguk Kim ◽  
Hyungsun Lim ◽  
Airan Liu ◽  
Shuling Hu ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Human Lung ◽  
Ex Vivo ◽  
Poly I:C ◽  
Human Model ◽  
Therapeutic Effects ◽  
Alveolar Fluid Clearance ◽  
Bacterial Killing ◽  
E Coli ◽  
Protein Permeability

BackgroundWe previously reported that microvesicles (MVs) released by human mesenchymal stem cells (MSC) were as effective as the cells themselves in both Escherichia coli lipopolysaccharide and live bacteria-induced acute lung injury (ALI) mice models. However, it remained unclear whether the biological effect of MSC MV can be applied to human ALI.MethodsIn the current study, we tested the therapeutic effects of MSC MVs in a well-established ex vivo perfused human model of bacterial pneumonia. Using human donor lungs not used for transplantation, we instilled E. coli bacteria intrabronchially and, 1 hour later, administered MSC MVs into the perfusate as therapy.ResultsAfter 6 hours, instillation of E. coli bacteria caused influx of inflammatory cells, which resulted in significant inflammation, lung protein permeability and pulmonary oedema formation. Administration of MSC MV significantly increased alveolar fluid clearance and reduced protein permeability and numerically lowered the bacterial load in the injured alveolus. The beneficial effect on bacterial killing was more pronounced with pretreatment of MSCs with a Toll-like receptor 3 agonist, polyinosinic:polycytidylic acid (Poly (I:C)), prior to the isolation of MVs. Isolated human alveolar macrophages had increased antimicrobial activity with MSC MV treatment in vitro as well. Although oxygenation and lung compliance levels were similar between injury and treatment groups, administration of MSC MVs numerically decreased median pulmonary artery pressure at 6 hours.ConclusionsIn summary, MSC MVs increased alveolar fluid clearance and reduced lung protein permeability, and pretreatment with Poly (I:C) enhanced the antimicrobial activity of MVs in an ex vivo perfused human lung with severe bacteria pneumonia.

scholarly journals Increased Survival of Antibiotic-Resistant Escherichia coli inside Macrophages

2012 ◽  
Vol 57 (1) ◽  
pp. 189-195 ◽  
Author(s):  
Migla Miskinyte ◽  
Isabel Gordo
Keyword(s):  
Escherichia Coli ◽  
Antibiotic Resistance ◽  
Bacterial Infections ◽  
Resistance Mutation ◽  
Fitness Cost ◽  
Resistance Mutations ◽  
Content Type ◽  
E Coli ◽  
Fitness Effects ◽  
K 12

ABSTRACTMutations causing antibiotic resistance usually incur a fitness cost in the absence of antibiotics. The magnitude of such costs is known to vary with the environment. Little is known about the fitness effects of antibiotic resistance mutations when bacteria confront the host's immune system. Here, we study the fitness effects of mutations in therpoB,rpsL, andgyrAgenes, which confer resistance to rifampin, streptomycin, and nalidixic acid, respectively. These antibiotics are frequently used in the treatment of bacterial infections. We measured two important fitness traits—growth rate and survival ability—of 12Escherichia coliK-12 strains, each carrying a single resistance mutation, in the presence of macrophages. Strikingly, we found that 67% of the mutants survived better than the susceptible bacteria in the intracellular niche of the phagocytic cells. In particular, allE. colistreptomycin-resistant mutants exhibited an intracellular advantage. On the other hand, 42% of the mutants incurred a high fitness cost when the bacteria were allowed to divide outside of macrophages. This study shows that single nonsynonymous changes affecting fundamental processes in the cell can contribute to prolonged survival ofE. coliin the context of an infection.

Antimicrobial activity of raw soybean, soybean flour and roasted soybean extracted by ethanol-hexane method

2017 ◽  
Vol 119 (10) ◽  
pp. 2277-2286 ◽  
Author(s):  
Sireerat Laodheerasiri ◽  
Nirasha Horana Pathirage
Keyword(s):  
Antimicrobial Activity ◽  
Antimicrobial Activities ◽  
Diffusion Method ◽  
Antimicrobial Compounds ◽  
Soybean Flour ◽  
Hexane Extraction ◽  
Disk Diffusion Method ◽  
Content Type ◽  
E Coli ◽  
Inhibitory Compounds

Purpose The purpose of this paper is to determine the antimicrobial compounds extracted from various types of soybean materials; raw soybean, soybean flour and roasted soybean. Bacteria growth inhibition was tested in E.coli and S. aureus by disk diffusion method. Efficiency of antimicrobial activities were compared among the extracted solution. Design/methodology/approach Soybean (Glycine max) isoflavones contain the ability to inhibit the growth of many strains of microorganisms. The solid-liquid extraction, ethanol-hexane extraction, was modified to isolate the inhibitory compounds from the three different types of soybean materials. All crude extracts at various concentrations performed under different extracted solutions (75, 50, 25, 12.5, 6.25 and 3.125 percent) were tested with E. coli. and S. aureus to determine the antimicrobial activities and the minimum inhibition concentration (MIC). Disk diffusion method was chosen to study the antimicrobial activity of isoflavones. Findings Soybean flour extract inhibited the growth of E. coli and S. aureus more effective than roasted soybean and raw soybean, respectively. The MIC of inhibitory compounds extracted from soybean flour was 6.25 percent (0.031 mg/ml), roasted soybean was 25 percent (0.125 mg/ml) and raw soybean was 50 percent (0.250 mg/ml). Crude extracts of soybean flour and roasted soybean showed better results than raw soybean. All the three of extracted soybeans inhibited the growth of E. coli better than S. aureus. Originality/value Ethanol-hexane extraction was successfully used to isolate the antimicrobial compounds from raw soybean, soybean flour and roasted soybean. Comparison of antimicrobial activity showed that soybean flour contained the highest inhibition activity.

scholarly journals ANTIMICROBIAL ACTIVITY OF METHANOLIC EXTRACT OF LUDWIGIA PARVIFLORA L. AGAINST STANDARD BACTERIAL STRAINS AND COMPARISON OF ITS ACTIVITY WITH THAT OF STANDARD ANTIBIOTICS

2019 ◽  
pp. 430-432
Author(s):  
SHIBU GEORGE ◽  
MEVLIN JOY
Keyword(s):  
Antimicrobial Activity ◽  
Bacterial Infections ◽  
Methanolic Extract ◽  
Diffusion Method ◽  
Bacterial Strains ◽  
Disk Diffusion Method ◽  
E Coli ◽  
Whole Plant ◽  
The Common ◽  
Susceptibility Tests

Objective: The objective of this study was to evaluate the antimicrobial activity of methanolic extract of Ludwigia parviflora L. using standard bacterial strains and compare its activity with that of standard antibiotics. Methods: The antibacterial activity and antibiotic susceptibility tests were done by disk diffusion method using MTCC bacterial strains. Results: The study revealed that the methanolic extract of the whole plant of L. parviflora L. was effective to inhibit the growth of Staphylococcus aureus, Pseudomonas aeruginosa, Klebsiella pneumoniae, and Escherichia coli. Among the tested strains, S. aureus, P. aeruginosa, K. pneumoniae, and E. coli were more susceptible to the methanolic extract of L. parviflora than the commonly using antibiotic tetracycline 30 mcg. The activity of methanolic extract was also higher than the activity of gentamicin 10 mcg against the P. aeruginosa. Conclusion: The study concluded that the crude methanolic extract of the whole plant of L. parviflora L. is a good source for antibacterial agent against S. aureus, P. aeruginosa, K. pneumoniae, and E. coli. Hence, this plant can be used as a natural alternative to the common antibiotics such as gentamicin and tetracycline against common bacterial infections after validating its pharmacological and toxicological activities.

scholarly journals Metformin strengthens uroepithelial immunity against E. coli infection

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Rakesh Kumar Majhi ◽  
Soumitra Mohanty ◽  
Witchuda Kamolvit ◽  
John Kerr White ◽  
Andrea Scheffschick ◽  
...  
Keyword(s):  
Bacterial Infections ◽  
Treatment Strategies ◽  
First Line ◽  
Antidiabetic Drug ◽  
Oral Antidiabetic Drug ◽  
Bacterial Killing ◽  
E Coli ◽  
Oral Antidiabetic ◽  
Uroepithelial Cells

AbstractUrinary tract infection frequently caused by E. coli is one of the most common bacterial infections. Increasing antibiotic resistance jeopardizes successful treatment and alternative treatment strategies are therefore mandatory. Metformin, an oral antidiabetic drug, has been shown to activate macrophages in the protection against certain infecting microorganisms. Since epithelial cells often form the first line of defense, we here investigated the effect on uroepithelial cells during E. coli infection. Metformin upregulated the human antimicrobial peptides cathelicidin LL-37 and RNase7 via modulation of the TRPA1 channel and AMPK pathway. Interestingly, metformin stimulation enriched both LL-37 and TRPA1 in lysosomes. In addition, metformin specifically increased nitric oxide and mitochondrial, but not cytosolic ROS. Moreover, metformin also triggered mRNA expression of the proinflammatory cytokines IL1B, CXCL8 and growth factor GDF15 in human uroepithelial cells. The GDF15 peptide stimulated macrophages increased LL-37 expression, with increased bacterial killing. In conclusion, metformin stimulation strengthened the innate immunity of uroepithelial cells inducing enhanced extracellular and intracellular bacterial killing suggesting a favorable role of metformin in the host defense.

scholarly journals AsnB is responsible for peptidoglycan precursor amidation in Clostridium difficile in the presence of vancomycin

Microbiology ◽  
2020 ◽  
Vol 166 (6) ◽  
pp. 567-578 ◽  
Author(s):  
Fariza Ammam ◽  
Delphine Patin ◽  
Héloise Coullon ◽  
Didier Blanot ◽  
Thierry Lambert ◽  
...  
Keyword(s):  
Clostridium Difficile ◽  
Gene Cluster ◽  
Enterococcus Faecalis ◽  
Type Species ◽  
Asparagine Synthetase ◽  
Structure Modification ◽  
Content Type ◽  
E Coli ◽  
Link Type ◽  
Peptidoglycan Structure

Clostridium difficile 630 possesses a cryptic but functional gene cluster vanG Cd homologous to the vanG operon of Enterococcus faecalis . Expression of vanG Cd in the presence of subinhibitory concentrations of vancomycin is accompanied by peptidoglycan amidation on the meso-DAP residue. In this paper, we report the presence of two potential asparagine synthetase genes named asnB and asnB2 in the C. difficile genome whose products were potentially involved in this peptidoglycan structure modification. We found that asnB expression was only induced when C. difficile was grown in the presence of vancomycin, yet independently from the vanG Cd resistance and regulation operons. In addition, peptidoglycan precursors were not amidated when asnB was inactivated. No change in vancomycin MIC was observed in the asnB mutant strain. In contrast, overexpression of asnB resulted in the amidation of most of the C. difficile peptidoglycan precursors and in a weak increase of vancomycin susceptibility. AsnB activity was confirmed in E. coli . In contrast, the expression of the second asparagine synthetase, AsnB2, was not induced in the presence of vancomycin. In summary, our results demonstrate that AsnB is responsible for peptidoglycan amidation of C. difficile in the presence of vancomycin.

scholarly journals Enterococcus faecalis Enhances Expression and Activity of the Enterohemorrhagic Escherichia coli Type III Secretion System

mBio ◽  
2019 ◽  
Vol 10 (6) ◽  
Author(s):  
Elizabeth A. Cameron ◽  
Vanessa Sperandio ◽  
Gary M. Dunny
Keyword(s):  
Enterococcus Faecalis ◽  
Type Iii Secretion ◽  
Type Iii Secretion System ◽  
Secretion System ◽  
Host Cells ◽  
Cell Contact ◽  
Content Type ◽  
E Coli ◽  
Type Iii ◽  
Expression And Activity

ABSTRACT The gut microbiota can significantly impact invading pathogens and the disease they cause; however, many of the mechanisms that dictate commensal-pathogen interactions remain unclear. Enterohemorrhagic Escherichia coli (EHEC) is a potentially lethal human intestinal pathogen that uses microbiota-derived molecules as cues to efficiently regulate virulence factor expression. Here, we investigate the interaction between EHEC and Enterococcus faecalis, a common human gut commensal, and show that E. faecalis affects both expression and activity of the EHEC type III secretion system (T3SS) via two distinct mechanisms. First, in the presence of E. faecalis there is increased transcription of genes encoding the EHEC T3SS. This leads to increased effector translocation and ultimately greater numbers of pedestals formed on host cells. The same effect was observed with several strains of enterococci, suggesting that it is a general characteristic of this group. In a mechanism separate from E. faecalis-induced transcription of the T3SS, we report that an E. faecalis-secreted protease, GelE, cleaves a critical structural component of the EHEC T3SS, EspB. Our data suggest that this cleavage actually increases effector translocation by the T3SS, supporting a model where EspB proteolysis promotes maximum T3SS activity. Finally, we report that treatment of EHEC with E. faecalis-conditioned cell-free medium is insufficient to induce increased T3SS expression, suggesting that this effect relies on cell contact between E. faecalis and EHEC. This work demonstrates a complex interaction between a human commensal and pathogen that impacts both expression and function of a critical virulence factor. IMPORTANCE This work reveals a complex and multifaceted interaction between a human gut commensal, Enterococcus faecalis, and a pathogen, enterohemorrhagic E. coli. We demonstrate that E. faecalis enhances expression of the enterohemorrhagic E. coli type III secretion system and that this effect likely depends on cell contact between the commensal and the pathogen. Additionally, the GelE protease secreted by E. faecalis cleaves a critical structural component of the EHEC type III secretion system. In agreement with previous studies, we find that this cleavage actually increases effector protein delivery into host cells by the secretion system. This work demonstrates that commensal bacteria can significantly shape expression and activity of pathogen virulence factors, which may ultimately shape the progression of disease.

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