Baicalein Inhibits Staphylococcus aureus Biofilm Formation and the Quorum Sensing System In Vitro

Biofilm formed by Staphylococcus aureus significantly enhances antibiotic resistance by inhibiting the penetration of antibiotics, resulting in an increasingly serious situation. This study aimed to assess whether baicalein can prevent Staphylococcus aureus biofilm formation and whether it may have...

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Main Authors:	Chen, Yan, Liu, Tangjuan, Wang, Ke, Hou, Changchun, Cai, Shuangqi, Huang, Yingying, Du, Zhongye, Huang, Hong, Kong, Jinliang, Chen, Yiqiang
Format:	Online
Language:	English
Published:	Public Library of Science 2016
Online Access:	https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4851419/

id	pubmed-4851419
recordtype	oai_dc
spelling	pubmed-48514192016-05-07 Baicalein Inhibits Staphylococcus aureus Biofilm Formation and the Quorum Sensing System In Vitro Chen, Yan Liu, Tangjuan Wang, Ke Hou, Changchun Cai, Shuangqi Huang, Yingying Du, Zhongye Huang, Hong Kong, Jinliang Chen, Yiqiang Research Article Biofilm formed by Staphylococcus aureus significantly enhances antibiotic resistance by inhibiting the penetration of antibiotics, resulting in an increasingly serious situation. This study aimed to assess whether baicalein can prevent Staphylococcus aureus biofilm formation and whether it may have synergistic bactericidal effects with antibiotics in vitro. To do this, we used a clinically isolated strain of Staphylococcus aureus 17546 (t037) for biofilm formation. Virulence factors were detected following treatment with baicalein, and the molecular mechanism of its antibiofilm activity was studied. Plate counting, crystal violet staining, and fluorescence microscopy revealed that 32 μg/mL and 64 μg/mL baicalein clearly inhibited 3- and 7-day biofilm formation in vitro. Moreover, colony forming unit count, confocal laser scanning microscopy, and scanning electron microscopy showed that vancomycin (VCM) and baicalein generally enhanced destruction of biofilms, while VCM alone did not. Western blotting and real-time quantitative polymerase chain reaction analyses (RTQ-PCR) confirmed that baicalein treatment reduced staphylococcal enterotoxin A (SEA) and α-hemolysin (hla) levels. Most strikingly, real-time qualitative polymerase chain reaction data demonstrated that 32 μg/mL and 64 μg/mL baicalein downregulated the quorum-sensing system regulators agrA, RNAIII, and sarA, and gene expression of ica, but 16 μg/mL baicalein had no effect. In summary, baicalein inhibited Staphylococcus aureus biofilm formation, destroyed biofilms, increased the permeability of vancomycin, reduced the production of staphylococcal enterotoxin A and α-hemolysin, and inhibited the quorum sensing system. These results support baicalein as a novel drug candidate and an effective treatment strategy for Staphylococcus aureus biofilm-associated infections. Public Library of Science 2016-04-29 /pmc/articles/PMC4851419/ /pubmed/27128436 http://dx.doi.org/10.1371/journal.pone.0153468 Text en © 2016 Chen et al http://creativecommons.org/licenses/by/4.0/ This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/) , which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
repository_type	Open Access Journal
institution_category	Foreign Institution
institution	US National Center for Biotechnology Information
building	NCBI PubMed
collection	Online Access
language	English
format	Online
author	Chen, Yan Liu, Tangjuan Wang, Ke Hou, Changchun Cai, Shuangqi Huang, Yingying Du, Zhongye Huang, Hong Kong, Jinliang Chen, Yiqiang
spellingShingle	Chen, Yan Liu, Tangjuan Wang, Ke Hou, Changchun Cai, Shuangqi Huang, Yingying Du, Zhongye Huang, Hong Kong, Jinliang Chen, Yiqiang Baicalein Inhibits Staphylococcus aureus Biofilm Formation and the Quorum Sensing System In Vitro
author_facet	Chen, Yan Liu, Tangjuan Wang, Ke Hou, Changchun Cai, Shuangqi Huang, Yingying Du, Zhongye Huang, Hong Kong, Jinliang Chen, Yiqiang
author_sort	Chen, Yan
title	Baicalein Inhibits Staphylococcus aureus Biofilm Formation and the Quorum Sensing System In Vitro
title_short	Baicalein Inhibits Staphylococcus aureus Biofilm Formation and the Quorum Sensing System In Vitro
title_full	Baicalein Inhibits Staphylococcus aureus Biofilm Formation and the Quorum Sensing System In Vitro
title_fullStr	Baicalein Inhibits Staphylococcus aureus Biofilm Formation and the Quorum Sensing System In Vitro
title_full_unstemmed	Baicalein Inhibits Staphylococcus aureus Biofilm Formation and the Quorum Sensing System In Vitro
title_sort	baicalein inhibits staphylococcus aureus biofilm formation and the quorum sensing system in vitro
description	Biofilm formed by Staphylococcus aureus significantly enhances antibiotic resistance by inhibiting the penetration of antibiotics, resulting in an increasingly serious situation. This study aimed to assess whether baicalein can prevent Staphylococcus aureus biofilm formation and whether it may have synergistic bactericidal effects with antibiotics in vitro. To do this, we used a clinically isolated strain of Staphylococcus aureus 17546 (t037) for biofilm formation. Virulence factors were detected following treatment with baicalein, and the molecular mechanism of its antibiofilm activity was studied. Plate counting, crystal violet staining, and fluorescence microscopy revealed that 32 μg/mL and 64 μg/mL baicalein clearly inhibited 3- and 7-day biofilm formation in vitro. Moreover, colony forming unit count, confocal laser scanning microscopy, and scanning electron microscopy showed that vancomycin (VCM) and baicalein generally enhanced destruction of biofilms, while VCM alone did not. Western blotting and real-time quantitative polymerase chain reaction analyses (RTQ-PCR) confirmed that baicalein treatment reduced staphylococcal enterotoxin A (SEA) and α-hemolysin (hla) levels. Most strikingly, real-time qualitative polymerase chain reaction data demonstrated that 32 μg/mL and 64 μg/mL baicalein downregulated the quorum-sensing system regulators agrA, RNAIII, and sarA, and gene expression of ica, but 16 μg/mL baicalein had no effect. In summary, baicalein inhibited Staphylococcus aureus biofilm formation, destroyed biofilms, increased the permeability of vancomycin, reduced the production of staphylococcal enterotoxin A and α-hemolysin, and inhibited the quorum sensing system. These results support baicalein as a novel drug candidate and an effective treatment strategy for Staphylococcus aureus biofilm-associated infections.
publisher	Public Library of Science
publishDate	2016
url	https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4851419/
_version_	1613573491935674368

Baicalein Inhibits Staphylococcus aureus Biofilm Formation and the Quorum Sensing System In Vitro

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