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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François Chassagne1†, Xinyi Huang1†, James T. Lyles1 and Cassandra L. Quave1,2* 1Center for the Study of Human Health, Emory University, Atlanta, GA, United States 2Department of Dermatology, Emory University, Atlanta, GA, United States In the search for new therapeutic solutions to address an increasing number of multidrug-resistant bacterial pathogens, secondary metabolites from plants have proven to be a rich source of antimicrobial compounds. Ginkgo biloba, a tree native to China, has been spread around the world as an ornamental tree. Its seeds have been used as snacks and medical mater...
Source: Frontiers in Microbiology - Category: Microbiology Source Type: research
Conclusion Genomic analyses herein performed allowed us to confirm the recently (Pérez-Cataluña et al., 2018a,b) suggested amendment of A. butzleri as Al. butzlerii, comb. nov. Antimicrobial susceptibility tests defined Ab 55 and Ab 6V strains as resistant to vancomycin, tetracyclin, nalidixic acid (only Ab 55 whereas Ab 6V is intermediate resistant), erythromycin, and β-lactam antibiotics. Moreover, in our strains isolated from shellfish, we identified numerous virulence, antibiotic, and heavy metal resistance determinants, also additional to those previously found in the genome sequenced A. butzleri ...
Source: Frontiers in Microbiology - Category: Microbiology Source Type: research
Discussion Until now, the main tool used for bacterial identification based on NGS of the 16S–23S rRNA encoding region was de novo assembly followed by BLASTN on NCBI database (Sabat et al., 2017), however, there was no evidence that it would be the most accurate and/or fastest method available. The de novo assembly and BLASTN is the only approach of the three that works at the contig level, and both the OTU clustering and mapping are performed at the read level. Using the NCBI database for these two last approaches would have resulted in odd results, since the NCBI database includes sequences that do not belong to ...
Source: Frontiers in Microbiology - Category: Microbiology Source Type: research
Abstract We used a green sol-gel synthesis method to fabricate a novel nanoporous copper aluminosilicate (CAS) material. Nanoporous CAS was characterized using X-ray powder diffraction (XRD), field emission transmission and scanning electron microscopies (FE-TEM/FE-SEM), Fourier transform infrared (FTIR) spectroscopy, and optical analyses. The CAS was also evaluated for use as a promising disinfectant for the inactivation of waterborne pathogens. The antimicrobial action and minimum inhibitory concentration (MIC) of this CAS disinfectant were determined against eight microorganisms (Escherichia coli, Salmonella en...
Source: Environmental Science and Pollution Research International - Category: Environmental Health Authors: Tags: Environ Sci Pollut Res Int Source Type: research
In this study, a C-terminal 6 _ His tagged recombinant TC-1 was expressed as a secreted peptide in Pichia pastoris, for the first time. The recombinant P. pastoris was inoculated in to BMMY culture medium, incubation with 5 μl/ml absolute methanol for 72 h at 30 °C. The TC-1 peptide was concentrated with nickel affinity chromatography and electrophoresis on 16% acrylamide gels. The molecular weight of recombinant TC-1 is approximately 8 kDa and under these conditions, the concentration of TC-1 considered 190 μg/ml that determined by the Bradford method. The antimicrobial activity test (Minimum Inhibit...
Source: Microbial Pathogenesis - Category: Infectious Diseases Source Type: research
This study might be helpful in understanding the anti-adhesion mechanism of probiotics against pathogens.
Source: Canadian Journal of Microbiology - Category: Microbiology Authors: Source Type: research
The objective of this study was to investigate the effect of photodynamic inactivation, using two xanthene dyes (rose bengal and erythrosine) as photosensitizing agents and green LED as a light source, against Staphylococcus aureus, Listeria innocua, Enterococcus hirae and Escherichia coli in both planktonic and biofilm states. Both photosensitizing agents were able to control planktonic cells of all bacteria tested. The treatments altered the physicochemical properties of cells surface and also induced potassium leakage, indicating damage of cell membranes. Although higher concentrations of the photosensitizing agents (ra...
Source: Molecules - Category: Chemistry Authors: Tags: Article Source Type: research
C, Capita R, Alonso-Calleja C Abstract The biofilms formed by Salmonella Hadar (SH174), Listeria monocytogenes (LM6), methicillin-resistant Staphylococcus aureus (MRSA125) and vancomycin-resistant Enterococcus faecium (VRE61s) on polystyrene and glass after 24 h and 72 h of incubation at 37 °C were examined by confocal laser scanning microscopy (CLSM) after staining with SYTO9 and propidium iodide (PI). A lower average biovolume (P 
Source: Food Microbiology - Category: Food Science Authors: Tags: Food Microbiol Source Type: research
Authors: Cao J, Gao S, Chen J, Zhu B, Min R, Wang P Abstract The present study prepared 2 types of DNA diagnostic chips based on 16S ribosomal DNA (rDNA) and 18S-28S rDNA, and evaluated their values in the detection of pathogens in intracranial bacterial/fungal infections. A total of 14 probes of bacteria (Klebsiella pneumonia, Acinetobacter baumannii, Pseudomonas aeruginosa, Escherichia coli, Haemophilus influenza, Stenotrophomonas maltophilia, Neisseria meningitidis, Enterobacter spp., Enterococcus faecalis, Enterococcus faecium, Listeria monocytogenes, Staphylococcus aureus, Streptococcus pneumonia and coagulase...
Source: Experimental and Therapeutic Medicine - Category: General Medicine Tags: Exp Ther Med Source Type: research
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
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