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Decoding the proteomic changes involved in the biofilm formation of Enterococcus faecalis SK460 to elucidate potential biofilm determinants

BACKGROUND: Enterococcus faecalis is a major clinically relevant nosocomial bacterial pathogen frequently isolated from polymicrobial infections. The biofilm forming ability of E. faecalis attributes a key role in its virulence and drug resistance. Biofilm cells are phenotypically and metabolically...

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Autores principales: Suryaletha, Karthika, Narendrakumar, Lekshmi, John, Joby, Radhakrishnan, Megha Periyappilly, George, Sanil, Thomas, Sabu
Formato: Online Artículo Texto
Lenguaje:English
Publicado: BioMed Central 2019
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6599329/
https://www.ncbi.nlm.nih.gov/pubmed/31253082
http://dx.doi.org/10.1186/s12866-019-1527-2
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author Suryaletha, Karthika
Narendrakumar, Lekshmi
John, Joby
Radhakrishnan, Megha Periyappilly
George, Sanil
Thomas, Sabu
author_facet Suryaletha, Karthika
Narendrakumar, Lekshmi
John, Joby
Radhakrishnan, Megha Periyappilly
George, Sanil
Thomas, Sabu
author_sort Suryaletha, Karthika
collection PubMed
description BACKGROUND: Enterococcus faecalis is a major clinically relevant nosocomial bacterial pathogen frequently isolated from polymicrobial infections. The biofilm forming ability of E. faecalis attributes a key role in its virulence and drug resistance. Biofilm cells are phenotypically and metabolically different from their planktonic counterparts and many aspects involved in E. faecalis biofilm formation are yet to be elucidated. The strain E. faecalis SK460 used in the present study is esp (Enterococcal surface protein) and fsr (two-component signal transduction system) negative non-gelatinase producing strong biofilm former isolated from a chronic diabetic foot ulcer patient. We executed a label-free quantitative proteomic approach to elucidate the differential protein expression pattern at planktonic and biofilm stages of SK460 to come up with potential determinants associated with Enterococcal biofilm formation. RESULTS: The Gene Ontology and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses of proteomic data revealed that biofilm cells expressed higher levels of proteins which are associated with glycolysis, amino acid biosynthesis, biosynthesis of secondary metabolites, microbial metabolism in diverse environments and stress response factors. Besides these basic survival pathways, LuxS-mediated quorum sensing, arginine metabolism, rhamnose biosynthesis, pheromone and adhesion associated proteins were found to be upregulated during the biofilm transit from planktonic stages. The selected subsets were validated by quantitative real-time PCR. In silico functional interaction analysis revealed that the genes involved in upregulated pathways pose a close molecular interaction thereby coordinating the regulatory network to thrive as a biofilm community. CONCLUSIONS: The present study describes the first report of the quantitative proteome analysis of an esp and fsr negative non gelatinase producing E. faecalis. Proteome analysis evidenced enhanced expression of glycolytic pathways, stress response factors, LuxS quorum signaling system, rhamnopolysaccharide synthesis and pheromone associated proteins in biofilm phenotype. We also pointed out the relevance of LuxS quorum sensing and pheromone associated proteins in the biofilm development of E. faecalis which lacks the Fsr quorum signaling system. These validated biofilm determinants can act as potential inhibiting targets in Enterococcal infections. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1186/s12866-019-1527-2) contains supplementary material, which is available to authorized users.
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spelling pubmed-65993292019-07-11 Decoding the proteomic changes involved in the biofilm formation of Enterococcus faecalis SK460 to elucidate potential biofilm determinants Suryaletha, Karthika Narendrakumar, Lekshmi John, Joby Radhakrishnan, Megha Periyappilly George, Sanil Thomas, Sabu BMC Microbiol Research Article BACKGROUND: Enterococcus faecalis is a major clinically relevant nosocomial bacterial pathogen frequently isolated from polymicrobial infections. The biofilm forming ability of E. faecalis attributes a key role in its virulence and drug resistance. Biofilm cells are phenotypically and metabolically different from their planktonic counterparts and many aspects involved in E. faecalis biofilm formation are yet to be elucidated. The strain E. faecalis SK460 used in the present study is esp (Enterococcal surface protein) and fsr (two-component signal transduction system) negative non-gelatinase producing strong biofilm former isolated from a chronic diabetic foot ulcer patient. We executed a label-free quantitative proteomic approach to elucidate the differential protein expression pattern at planktonic and biofilm stages of SK460 to come up with potential determinants associated with Enterococcal biofilm formation. RESULTS: The Gene Ontology and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses of proteomic data revealed that biofilm cells expressed higher levels of proteins which are associated with glycolysis, amino acid biosynthesis, biosynthesis of secondary metabolites, microbial metabolism in diverse environments and stress response factors. Besides these basic survival pathways, LuxS-mediated quorum sensing, arginine metabolism, rhamnose biosynthesis, pheromone and adhesion associated proteins were found to be upregulated during the biofilm transit from planktonic stages. The selected subsets were validated by quantitative real-time PCR. In silico functional interaction analysis revealed that the genes involved in upregulated pathways pose a close molecular interaction thereby coordinating the regulatory network to thrive as a biofilm community. CONCLUSIONS: The present study describes the first report of the quantitative proteome analysis of an esp and fsr negative non gelatinase producing E. faecalis. Proteome analysis evidenced enhanced expression of glycolytic pathways, stress response factors, LuxS quorum signaling system, rhamnopolysaccharide synthesis and pheromone associated proteins in biofilm phenotype. We also pointed out the relevance of LuxS quorum sensing and pheromone associated proteins in the biofilm development of E. faecalis which lacks the Fsr quorum signaling system. These validated biofilm determinants can act as potential inhibiting targets in Enterococcal infections. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1186/s12866-019-1527-2) contains supplementary material, which is available to authorized users. BioMed Central 2019-06-28 /pmc/articles/PMC6599329/ /pubmed/31253082 http://dx.doi.org/10.1186/s12866-019-1527-2 Text en © The Author(s). 2019 Open AccessThis article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.
spellingShingle Research Article
Suryaletha, Karthika
Narendrakumar, Lekshmi
John, Joby
Radhakrishnan, Megha Periyappilly
George, Sanil
Thomas, Sabu
Decoding the proteomic changes involved in the biofilm formation of Enterococcus faecalis SK460 to elucidate potential biofilm determinants
title Decoding the proteomic changes involved in the biofilm formation of Enterococcus faecalis SK460 to elucidate potential biofilm determinants
title_full Decoding the proteomic changes involved in the biofilm formation of Enterococcus faecalis SK460 to elucidate potential biofilm determinants
title_fullStr Decoding the proteomic changes involved in the biofilm formation of Enterococcus faecalis SK460 to elucidate potential biofilm determinants
title_full_unstemmed Decoding the proteomic changes involved in the biofilm formation of Enterococcus faecalis SK460 to elucidate potential biofilm determinants
title_short Decoding the proteomic changes involved in the biofilm formation of Enterococcus faecalis SK460 to elucidate potential biofilm determinants
title_sort decoding the proteomic changes involved in the biofilm formation of enterococcus faecalis sk460 to elucidate potential biofilm determinants
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6599329/
https://www.ncbi.nlm.nih.gov/pubmed/31253082
http://dx.doi.org/10.1186/s12866-019-1527-2
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