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Background Bacteria can respond to antibiotics in the environment by histidine kinase (HK) sensor then induce drug-resistance. In this article,antibiotic susceptibility and ESBLs genes of β-lactam-resistant E. coli interfered by I. japonica were investigated to reveal I. japonica can be HK inhibitor candidate[1]. Methods E-test were applied to measure the MIC of E. coli to penicillin G and cefotaxime sodium according to 2017CLSI. Microplate dilution methods were applied to explore sensitivity variation of penicillin G and cefotaxime sodium of Escherichia coli, which contain only one single β-lactamase gene. Real-time fluorescent quantitative PCR were performed to determine the inducing effects of penicillin G and cefotaxime sodium to E. coli TEM, SHV, CTX-M and KPC single gene expression, and the interrupting effect of I. japonica extracts. Immobilized metal ion affinity chromatography and bacterial protein phosphorylation detection kit were performed to determine the change of bacterial protein phosphorylation concentration of Escherichia coli, after the induction of 1/4 penicillin G and cefotaxime sodium, and the interrupting effect of I. japonica extracts,HK inhibitor closantel was used as the positive control. Results 1/4 MIC penicillin G or cefotaxime sodium could induce more than 10 times elevation of TEM, SHV and CTX-M mRNAs. While, I. japonica aqueous extracts (250 mg/mL) and ethanol extracts (100 µg/mL or 50 µg/mL) could decreased more than 40% of gene expression induced by antibiotics. I. japonica extracts could significantly enhance the sensitivity of β-lactam antibiotic-resistant E. coli strains to penicillin G or cefotaxime sodium, and could block the TEM, CTX-M and SHV mRNA induced by 1/4 MIC concentration antibiotics. Penicillin G and cefotaxime sodium at 1/4 MIC induced the protein phosphorylation of TEM, SHV and CTX-M promoted. Closantel (132.5 µg/mL), I. japonica aqueous extracts (250 mg/mL) and ethanol extracts (100 µg/mL) could inhibit the protein phosphorylation induced by above mentioned antibiotics. Conclusion I. japonica extracts can enhance the sensitivity of β-lactam antibiotic-resistant Escherichia coli. The mechanism may be that I. japonica extracts can be used as the inhibitor of HK phosphorylation, inhibit the transmission of antibiotic signal in TCSS, and reduce the expression of ESBLs gene. |
