Enhancement of the antibacterial activity of an E. faecalis strain by the heterologous expression of enterocin A

Publication date: Available online 10 July 2018Source: Journal of BiotechnologyAuthor(s): Carlos Eduardo Serrano-Maldonado, Maricarmen QuirascoAbstractThe genus Enterococcus occurs as native microbiota of fermented products due to its broad environmental distribution and its resistance to salt concentrations. Enterococcus faecalis F, a non-pathogenic strain isolated from a ripened cheese, has demonstrated useful enzymatic capabilities, a probiotic behavior and antibacterial activity against some food-borne pathogens, mainly due to peptidoglycan hydrolase activity. Its use as a natural pathogen-control agent could be further enhanced through the production of a bacteriocin, e.g. Enterocin A, because of its remarkable antilisterial activity. In this work, a markerless allelic insertion method was used to obtain an enterococcal strain capable of producing a functional enterocin. Agar diffusion tests showed that the recombinant strain was active against Staphylococcus aureus, Listeria monocytogenes and the pathogenic strain E. faecalis V583. When grown in liquid culture together with L. monocytogenes, it attained a two-log reduction of the pathogen counts in lesser time relative to the native strain. Because the DNA construction is integrated into the chromosome, the improved strain avoids the use of antibiotics as selective pressure; besides, it does not require an inductor because of the inclusion of a constitutive promoter in the construction. Its technological and antibacteri...
Source: Journal of Biotechnology - Category: Biotechnology Source Type: research

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Publication date: August 2018Source: Journal of Environmental Chemical Engineering, Volume 6, Issue 4Author(s): Mohamed Azab El-Liethy, Khalid Z. Elwakeel, Mohammed S. AhmedAbstractMagnetic disinfectants were achieved through the polymerization of thiourea and formaldahyde in the presence of magnetite nano particles (MTUF), the as-prepared MTUF was loaded with Ag(I) or Au(III). The obtained disinfectants (MTUF-Ag and MTUF-Au) were test for some selected pathogenic strains deactivation. The toxicity of MTUF before and after Ag(I) or Au(II) loading was estimated. The antimicrobial activity tests of MTUF-Ag and MTUF-Au were c...
Source: Journal of Environmental Chemical Engineering - Category: Chemistry Source Type: research
Abstract One-pot synthesis of a new magnetic disinfectant was achieved through the polymerization of thiourea and formaldehyde in the presence of magnetite nanoparticles (MTUF). The obtained magnetic chelating resin was loaded with Ag(I) ions. This material was tested as a disinfectant for water pathogenic microorganism's deactivation. The toxicity of MTUF before and after Ag(I) loading was estimated. The antimicrobial activity tests of MTUF-Ag were carried out against Escherichia coli, Salmonella Typhimurium, and Pseudomonas aeruginosa as examples of Gram-negative bacteria; Listeria monocytogenes, Staphylococcus ...
Source: Environmental Science and Pollution Research International - Category: Environmental Health Authors: Tags: Environ Sci Pollut Res Int Source Type: research
Abstract The bacteriocin enterocin-B contains broad anti-microbial spectrum against several gram positive, negative pathogenic bacteria was cloned, overexpressed and purified from Enterococcus faecium por1. The molecular weight of the bacteriocin enterocin-B was observed around 7.2 kDa and interacting, formation of heterodimer with another bacteriocin enterocin-A from the same organism by protein-protein docking and molecular dynamics simulation studies. The heterodimer of bacteriocin enterocin-A + B exhibited potential anti-bacterial, anti-biofilm activity against Staphylococcus aureus, Listeria monocytogen...
Source: International Journal of Biological Macromolecules - Category: Biochemistry Authors: Tags: Int J Biol Macromol Source Type: research
This study evaluated the effect of a novel formulation for starter culture associated with specific ripening conditions (NoNit™ technology) vs. a commercial» starter on the fate of selected pathogens and hygiene indicators during the fermentation and ripening of experimentally spiked salame nostrano (Italian dry sausage). Selected strains of Staphylococcus aureus 27R, Escherichia coli CSH26 K 12, Listeria innocua ATCC 33090 and Salmonella Derby 27 were inoculated into salami batter and challenged with two formulations of starter cultures (a commercial formulation and the NoNit™ formulation, consisting of ...
Source: Meat Science - Category: Food Science Source Type: research
Publication date: Available online 3 January 2018 Source:Microbial Pathogenesis Author(s): Shuai Wei, Ramachandran Chelliah, Byung-Jae Park, Joong-Hyun Park, Fereidoun Forghani, Youn-Seo Park, Min-Seok Cho, Dong-Suk Park, Deog-Hwan Oh The aim of the study was to identify and evaluate specific biomarkers to differentiate within Bacillus cereus group species from contaminated food samples with the use of real-time PCR. A total of 120 strains, comprising of 28 reference, 2 type, 78 wild strains of B. cereus and B. thuringiensis along with 12 strains representing 2 bacterial groups – B. mycoides, B. pseudomycoides, B. w...
Source: Microbial Pathogenesis - Category: Infectious Diseases Source Type: research
Conclusion: The presence of virulence genes in E. faecalis TA102 calls for careful monitoring of Enterococcus isolates for their safety parameters. PMID: 29238458 [PubMed]
Source: Iranian Journal of Microbiology - Category: Microbiology Tags: Iran J Microbiol Source Type: research
Abstract Host cell adhesion assays that provide quantitative insight on the potential of lactic acid bacteria (LAB) to inhibit adhesion of intestinal pathogens can be leveraged for the development of niche-specific anti-adhesion therapy. Herein, we report a dual-colour flow cytometry (FCM) analysis to assess the ability of probiotic Lactobacillus plantarum strains to impede adhesion of Enterococcus faecalis, Listeria monocytogenes and Staphylococcus aureus onto HT-29 cells. FCM in conjunction with a hierarchical cluster analysis could discern the anti-adhesion potential of L. plantarum strains, wherein the efficac...
Source: Microbiology - Category: Microbiology Authors: Tags: Microbiology Source Type: research
Publication date: February 2018 Source:LWT - Food Science and Technology, Volume 88 Author(s): Ahram Oh, Eric Banan-Mwine Daliri, Deog H. Oh In the present study, we screened for potential probiotics from 34 lactic acid bacteria (LAB) isolated from the Korean fermented soybean paste. The LAB were tested for their survival abilities in the simulated gastrointestinal conditions. Seven lactic acid bacteria namely Pediococcus acidilactici SDL 1402, Pediococcus acidilactici SDL 1405, Pediococcus acidilactici SDL 1406, Weissella cibaria SCCB 2306, Streptococcus thermophilus SCML 337, Streptococcus thermophilus SCML 300 and Ente...
Source: LWT Food Science and Technology - Category: Food Science Source Type: research
Abstract A range of amphiphilic sorbitan ethers has been synthesized in two steps from sorbitan following an acetalization/hydrogenolysis sequence. These sorbitan ethers and the acetal intermediates have been evaluated as antimicrobials against Gram-negative and Gram-positive bacteria. No antimicrobial activity was observed for Gram-negative bacteria. However, the compounds bearing a linear dodecyl chain exhibit antimicrobial activity (MIC as low as 8μg/mL) against Gram-positive bacteria such as Listeria monocytogenes, Enterococcus faecalis and Staphylococcus aureus. Encouraged by these preliminary results, dod...
Source: Bioorganic and Medicinal Chemistry Letters - Category: Chemistry Authors: Tags: Bioorg Med Chem Lett Source Type: research
Abstract There has been major interest by the scientific community in anti-virulence approaches against bacterial infections. However, partly due to a lack of viable lead compounds, anti-virulence therapeutics have yet to reach the clinic. Here we investigate the development of an anti-virulence lead targeting quorum sensing signal-biosynthesis, a process that is conserved in Gram positive bacterial pathogens. Some preliminary studies suggest that the small molecule ambuic acid is a signal biosynthesis inhibitor. To confirm this, we construct a methicillin-resistant Staphylococcus aureus (MRSA) strain that decoupl...
Source: Antimicrobial Agents and Chemotherapy - Category: Microbiology Authors: Tags: Antimicrob Agents Chemother Source Type: research
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