Data Sheet 2_Biofilm-mediated resistance to berberine in Escherichia coli.fasta

ObjectiveTo investigate the mechanism of biofilm-mediated resistance to berberine in Escherichia coli.
MethodsThe resistance of berberine against E. coli was induced by 1/2 MIC (minimum inhibitory concentration). Biofilm formation was detected by crystal violet staining. The mRNA level was detected by RT-qPCR, and the gene csgD was determined. the csgD-overexpressed strain was constructed. We measured the MIC of berberine against E. coli, as well as biofilm formation and the expression of mRNA.
ResultsThe MIC after berberine induction was more than 32 times than the MIC before induction. the biofilm was significantly increased at 24, 48 and 72 hours (p<0.01) after berberine induction. In addition, the amount of biofilm production at 24, 48 and 72 hours was 1.3, 1.51 and 1.98 times after berberine induction than that before induction, respectively. The expression of csgD gene was significantly increased (p=0.016) after induction compared with that before induction. the MIC of csgD-overexpressed strain was about 5.8 times that before induction. The expression of csgD gene was significantly increased (p=0.016), which was 5.8 times higher than that before induction. The MIC of csgD-overexpressed strain was 100 μg/mL. Biofilm formation in csgD-overexpressed strain was 2.9 times higher than that of the control. The expression of biofilm-related genes, bcsA, luxS and csgD, was 45, 22.5 and 1628 times higher than that of the control, respectively.
ConclusionBerberine might increase biofilm formation by inducing the expression of csgD gene, which might result in drug resistance in E. coli.

研究目的：探究大肠杆菌（Escherichia coli）生物被膜介导的小檗碱耐药机制。
研究方法：采用1/2最低抑菌浓度（minimum inhibitory concentration, MIC）诱导大肠杆菌对小檗碱产生耐药性。通过结晶紫染色法检测生物被膜形成情况；采用逆转录实时定量PCR（RT-qPCR）检测mRNA水平，并针对csgD基因开展相关研究。构建csgD过表达菌株，测定小檗碱对大肠杆菌的最低抑菌浓度，同时检测生物被膜形成量与mRNA表达水平。
研究结果：小檗碱诱导后的最低抑菌浓度较诱导前提升32倍以上。小檗碱诱导后24、48及72小时，大肠杆菌生物被膜形成量显著升高（p<0.01）；相较于诱导前，诱导后24、48、72小时的生物被膜生成量分别为诱导前的1.3、1.51及1.98倍。诱导后csgD基因的表达量显著升高（p=0.016）。csgD过表达菌株的最低抑菌浓度约为诱导前的5.8倍，其csgD基因表达量较对照组升高5.8倍（p=0.016），该菌株的最低抑菌浓度为100 μg/mL。csgD过表达菌株的生物被膜形成量较对照组高2.9倍；生物被膜相关基因bcsA、luxS及csgD的表达量分别较对照组升高45、22.5及1628倍。
研究结论：小檗碱可能通过诱导csgD基因的表达促进大肠杆菌生物被膜形成，进而导致大肠杆菌产生耐药性。