Emergence of Two AcrB Substitutions Conferring Multidrug Resistance to Salmonella spp.
Emergence of Two AcrB Substitutions Conferring Multidrug Resistance to Salmonella spp.
复制标题
两种 AcrB 取代的出现赋予沙门氏菌多重耐药性。
DOI：
10.1128/aac.01589-20
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发表时间：
2021-03
影响因子：
4.9
通讯作者：
Zeng Zhenling
中科院分区：
文献类型：
--
作者：
Yang Ling;Shi Haiyang;Zhang Lijuan;Lin Xiaoling;Wei Yinan;Jiang Hongxia;Zeng Zhenling
AcrAB-TolC是一种主要的三方多药外排泵，可对革兰氏阴性病原体中的多种化合物产生耐药性。为了研究AcrB在抗生素耐药性中的作用机制，人们通过定点突变的方法构建了许多AcrB突变体。摘要AcrAB-TolC是革兰氏阴性病原体中一种主要的三方多药外排泵，可对多种化合物产生耐药性。为了研究AcrB在抗生素耐药性中的作用机制，人们通过定点突变的方法构建了许多AcrB突变体。然而，对临床分离的病原体中自然发生的实际耐药相关突变体知之甚少。在这里，我们报告了两个新的AcrB取代，M78 I和P319 L，在临床分离的沙门氏菌菌株与高水平的环丙沙星耐药。构建表达检测到的acrB突变的质粒并将其导入SL 1344 ΔacrB。抗菌药物敏感性试验表明，AcrB M78 I，AcrB P319 L，和AcrB M78 I/319 L都赋予多种底物，包括氟喹诺酮类药物，红霉素，四环素，胆汁盐，和染料的亲和性降低。定点突变和MIC结果表明，M78 I的疏水性增加是AcrB M78 I突变体对氟喹诺酮类药物敏感性降低的原因之一。荧光标记实验表明，AcrB M78 I取代增强了底物与外排途径中某些氨基酸位点的结合（例如，位点Q89，E673，和F617）并减弱与其它氨基酸的结合（例如，S134和N274）。结构建模表明，与原始Pro残基相比，Leu的柔性增加有利于AcrB的功能旋转。AcrA 319 L使AcrB的功能旋转更加灵活;这使得底物流出更有效。为了更好地理解AcrAB-TolC药物外排的机制，需要进一步研究AcrA和AcrB之间的相互作用在AcrAB-TolC底物外排中的作用。
AcrAB-TolC is a major tripartite multidrug efflux pump conferring resistance to a wide variety of compounds in Gram-negative pathogens. Many AcrB mutants have been constructed through site-directed mutagenesis to probe the mechanism of AcrB function in antibiotic resistance. ABSTRACT AcrAB-TolC is a major tripartite multidrug efflux pump conferring resistance to a wide variety of compounds in Gram-negative pathogens. Many AcrB mutants have been constructed through site-directed mutagenesis to probe the mechanism of AcrB function in antibiotic resistance. However, much less is known about the actual drug resistance-related mutants that naturally occur in clinically isolated pathogens. Here, we report two novel AcrB substitutions, M78I and P319L, in clinically isolated Salmonella strains with high-level ciprofloxacin resistance. Plasmids expressing the detected acrB mutations were constructed and introduced into SL1344 ΔacrB. Antimicrobial susceptibility assays showed that AcrB M78I, AcrB P319L, and AcrB M78I/319L all conferred reduced susceptibilities to multiple substrates, including fluoroquinolones, erythromycin, tetracyclines, bile salts, and dyes. Site-directed mutagenesis and MIC results revealed that the increased hydrophobicity of M78I was one of the reasons the AcrB M78I mutant had lower susceptibility to fluoroquinolones. Fluorescence labeling experiments suggested that the AcrB M78I substitution enhanced the binding of substrates to certain amino acid sites in the efflux pathway (e.g., sites Q89, E673, and F617) and weakened the binding to other amino acids (e.g., S134 and N274). Structural modeling disclosed that the increased flexibility of Leu was favorable for the functional rotation of AcrB compared to the original Pro residue. AcrA 319L makes the functional rotation of AcrB more flexible; this enables substrate efflux more efficiently. In order to understand the mechanism of AcrAB-TolC drug efflux well, the interaction between AcrA and AcrB in the role of the substrate efflux of AcrAB-TolC should be further investigated.
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影响因子：
3.6
作者：
Husain F;Nikaido H
通讯作者：
Nikaido H
影响因子：
4.1
作者：
P. Rajapaksha;Ankit Pandeya;Yinan Wei
通讯作者：
P. Rajapaksha;Ankit Pandeya;Yinan Wei
DOI：
--
发表时间：
2020
期刊：
--
影响因子：
--
作者：
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通讯作者：
E. Grimsey;N. Weston;V. Ricci;Jack W. Stone;L. Piddock
影响因子：
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作者：
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通讯作者：
S. Schuster;M. Vávra;W. Kern
影响因子：
16.6
作者：
Zwama M;Yamasaki S;Nakashima R;Sakurai K;Nishino K;Yamaguchi A
通讯作者：
Yamaguchi A