Inhibitory Effect of Two Traditional Chinese Medicine Monomers, Berberine and Matrine, on the Quorum Sensing System of Antimicrobial-Resistant Escherichia coli.

Tong Sun,Jin-Ping Zheng,Dao-Jin Yu,Yuan-Jun Xu,Xin-Luo Zhang,Zheng-Yang Ou,Juan Hong,Xiao-Dong Li,Can Liu,Jing-Ling Zheng

doi:10.3389/fmicb.2019.02584

Abstract

The quorum sensing (QS) system controls bacterial biofilm formation, which is highly related to the virulence and resistance of pathogens. In the present study, the effect of two traditional Chinese medicine (TCM) monomers, berberine and matrine, on biofilm formation and QS-related gene expression of antimicrobial-resistant (AMR) Escherichia coli strains was investigated by laser scanning confocal microscopy (LSCM) observation and real-time PCR. The results indicated a roughly positive relationship between biofilm formation ability and antimicrobial resistance. LSCM observation showed that berberine and matrine inhibited biofilm formation of AMR E. coli strains at 1/2 minimal inhibitory concentration (MIC) (1/2 MIC berberine at OD630: 0.1020; 1/2 MIC matrine: OD630: 0.1045); furthermore, abnormal cell morphology such as rounded and elongated cells was also observed. This finding was consistent with the downregulation of QS-related genes: luxS, pfS, sdiA, hflX, motA, and fliA. At 1/2 MIC and 1/4 MIC concentrations of berberine, a significant downregulation of luxS, pfS, hflX, ftsQ, and ftsE was observed. The results indicate that berberine and matrine can inhibit biofilm formation by inhibiting the QS system and that berberine is more effective than matrine.

Highlights

The phenomenon of information transmission between chemical groups through chemical signals is called quorum sensing (QS) (Bassler et al, 1993)
Interbacterial communication is accomplished by the secretion of a signaling substance called an autoinducer (AI) that binds to the receptor protein and induces bioluminescence (Kim et al, 2004)
The QS system is classified into type I (LuxI/LuxR-mediated) and type II (LuxS/AI-mediated) systems, along with an oligopeptidemediated QS system

Summary

Introduction

The phenomenon of information transmission between chemical groups through chemical signals is called quorum sensing (QS) (Bassler et al, 1993). This process often occurs later in the stationary phase of bacteria (Rajput et al, 2016). Previous studies have shown that signaling molecules formed in Pseudomonas aeruginosa in the logarithmic growth phase increase the number of persister cells after treatment with ciprofloxacin (Moker et al, 2010). The formation of biofilms is related to the perception of bacteria about their surrounding environment and bacterial density (Kai, 2018). Some researchers speculate that biofilm formation in the QS system could be a potential drug target (Williams, 2002)

Methods

Results

Conclusion