The Global Consequence of Disruption of the AcrAB-TolC Efflux Pump in Salmonella enterica Includes Reduced Expression of SPI-1 and Other Attributes Required To Infect the Host
The Global Consequence of Disruption of the AcrAB-TolC Efflux Pump in Salmonella enterica Includes Reduced Expression of SPI-1 and Other Attributes Required To Infect the Host
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DOI：
10.1128/jb.00363-09
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发表时间：
2009-07-01
影响因子：
3.2
通讯作者：
Piddock, Laura J. V.
中科院分区：
文献类型：
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作者：
Webber, Mark A.;Bailey, Andrew M.;Piddock, Laura J. V.
RND 泵导致致病性的机制目前尚不清楚。使用 AcrAB-TolC 系统作为范例多药耐药外排泵，并以鼠伤寒沙门氏菌血清型作为模型病原体，我们证明了 AcrA、AcrB 和 TolC 都是沙门氏菌在体外有效粘附和侵袭上皮细胞和巨噬细胞所必需的。此外，AcrB 和 TolC 是沙门氏菌在家禽定植所必需的。缺乏acrA、acrB或tolC的突变体表现出参与发病机制的主要操纵子和蛋白质的差异表达。这些包括趋化性和运动性基因，包括 cheWY 和 flgLMK，以及 14 个沙门氏菌致病岛 (SPI)-1 编码的 III 型分泌系统基因，包括 sopE 和相关效应蛋白。逆转录 PCR 证实了其他两个鼠伤寒沙门氏菌背景中相同突变体的这些数据。蛋白质印迹显示 SipA、SipB 和 SipC 的产量减少。 AcrB 或 TolC 的缺失还导致这些突变体中趋化性和运动基因的广泛抑制，对于 acrB::aph 来说，这与运动性下降有关。对于缺乏功能性 acrA 或 acrB 基因的突变体，nap 和 nir 操纵子受到抑制，并且两种突变体在厌氧条件下生长不良。通过与相应失活基因的野生型等位基因反式互补，所有表型恢复至野生型。这些数据解释了缺乏 AcrAB-TolC 成分的突变体如何减弱，并且这种表型是编码参与致病性的蛋白质的众多基因表达减少的结果。抗生素耐药性和致病性之间的联系使 AcrAB-TolC 系统成为沙门氏菌生物学的基础。
The mechanisms by which RND pumps contribute to pathogenicity are currently not understood. Using the AcrAB-TolC system as a paradigm multidrug-resistant efflux pump and Salmonella enterica serovar Typhimurium as a model pathogen, we have demonstrated that AcrA, AcrB, and TolC are each required for efficient adhesion to and invasion of epithelial cells and macrophages by Salmonella in vitro. In addition, AcrB and TolC are necessary for Salmonella to colonize poultry. Mutants lacking acrA, acrB, or tolC showed differential expression of major operons and proteins involved in pathogenesis. These included chemotaxis and motility genes, including cheWY and flgLMK and 14 Salmonella pathogenicity island (SPI)-1-encoded type III secretion system genes, including sopE, and associated effector proteins. Reverse transcription-PCR confirmed these data for identical mutants in two other S. Typhimurium backgrounds. Western blotting showed reduced production of SipA, SipB, and SipC. The absence of AcrB or TolC also caused widespread repression of chemotaxis and motility genes in these mutants, and for acrB::aph, this was associated with decreased motility. For mutants lacking a functional acrA or acrB gene, the nap and nir operons were repressed, and both mutants grew poorly in anaerobic conditions. All phenotypes were restored to that of the wild type by trans-complementation with the wild-type allele of the respective inactivated gene. These data explain how mutants lacking a component of AcrAB-TolC are attenuated and that this phenotype is a result of decreased expression of numerous genes encoding proteins involved in pathogenicity. The link between antibiotic resistance and pathogenicity establishes the AcrAB-TolC system as fundamental to the biology of Salmonella.