Artesunate enhances the antibacterial effect of β-lactam antibiotics against Escherichia coli by increasing antibiotic accumulation via inhibition of the multidrug efflux pump system AcrAB-TolC
Artesunate enhances the antibacterial effect of β-lactam antibiotics against Escherichia coli by increasing antibiotic accumulation via inhibition of the multidrug efflux pump system AcrAB-TolC
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DOI：
10.1093/jac/dkr017
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发表时间：
2011-04-01
影响因子：
5.2
通讯作者：
Zhou, Hong
中科院分区：
文献类型：
--
作者：
Li, Bin;Yao, Qi;Zhou, Hong
目的：我们偶尔发现青蒿琥酯在体外能增强抗生素的抗菌作用。因此，本研究探讨青蒿琥酯对多种β-内酰胺类抗生素对大肠杆菌的增效作用及其可能的机制。方法：采用2倍稀释法和细菌动态生长法观察青蒿琥酯对大肠杆菌的抗菌作用。道诺霉素在E.用荧光分光光度法和激光共聚焦扫描显微镜观察大肠杆菌。用PCR方法观察AcrAB-TolC、AmpC和TEM-1 mRNA的表达。设计了针对AcrB的反义寡核苷酸（as-ODNs），并将其用于阻断AcrB基因在大肠杆菌中的表达。结果：青蒿琥酯本身无抗菌作用，但青蒿琥酯能显著增强β-内酰胺类抗生素对大肠杆菌的抗菌作用。coli ATCC 35218和E.大肠杆菌临床菌株。青蒿琥酯增加了道诺霉素在E. coliATCC 35218中，AcrAB-TolC的mRNA表达量明显降低，AcrAB-TolC是革兰氏阴性菌的一个重要的多药外排系统。靶向AcrB的as-ODN显著减少了细菌数量，但在额外的青蒿琥酯治疗后没有进一步减少。相反，青蒿琥酯失去了β-内酰胺类抗生素对大肠杆菌的增强作用。coli AG 100 A（AcrAB基因缺失菌株）和青蒿琥酯不能增加柔红霉素在E. coliAG100A。将pET 28 a-AcrB转化E. coli AG 100 A，青蒿琥酯恢复了β-内酰胺类抗生素的增强作用。结论：青蒿琥酯可增强多种β-内酰胺类抗生素对大肠杆菌的抗菌作用。大肠杆菌的耐药基因AcrAB-TolC可能与其对主要的多药耐药系统AcrAB-TolC的抑制有关。
Objectives: Occasionally, we found that artesunate enhanced the antibacterial effects of antibiotics in vitro. Therefore, the enhancement of various beta-lactam antibiotics by artesunate against Escherichia coli and the possible mechanism were investigated in the present study.Methods: Antibacterial effects were observed using the serial 2-fold dilution method and dynamic bacterial growth. Daunomycin accumulation within E. coli was observed using fluorospectrophotometry and laser confocal scanning microscopy. AcrAB-TolC, AmpC and TEM-1 mRNA expression was observed using a PCR method. Antisense oligonucleotides (as-ODNs) targeting AcrB were designed and used to block AcrB gene expression within E. coli ATCC 35218.Results: Although artesunate itself had no antibacterial ability, artesunate significantly increased the antibacterial effect of beta-lactam antibiotics against E. coli ATCC 35218 and an E. coli clinical strain. Artesunate increased daunomycin accumulation within E. coli ATCC 35218 in a dose-dependent manner and reduced the mRNA expression of AcrAB-TolC, an important multidrug efflux system for Gram-negative bacteria. The bacterial number was significantly reduced by as-ODN targeting AcrB, but did not further decrease after additional artesunate treatment. In contrast, artesunate lost its enhancement of beta-lactam antibiotics against E. coli AG100A, a strain lacking the gene encoding AcrAB, and artesunate did not increase daunomycin accumulation within E. coli AG100A. After the transformation of pET28a-AcrB into E. coli AG100A, artesunate regained enhancement of beta-lactam antibiotics. Furthermore, artesunate did not inhibit the expression of AmpC and TEM-1 mRNA.Conclusions: Artesunate enhances the antibacterial effect of various beta-lactam antibiotics against E. coli, which might be associated with the suppression of a major multidrug resistance system, AcrAB-TolC.