SmvA, and not AcrB, is the major efflux pump for acriflavine and related compounds in Salmonella enterica serovar Typhimurium
SmvA, and not AcrB, is the major efflux pump for acriflavine and related compounds in Salmonella enterica serovar Typhimurium
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DOI：
10.1093/jac/dkn407
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发表时间：
2008-12-01
影响因子：
5.2
通讯作者：
Mora, Guido C.
中科院分区：
文献类型：
--
作者：
Villagra, Nicolas A.;Hidalgo, Alejandro A.;Mora, Guido C.
为研究SmvA泵在鼠伤寒沙门氏菌（Salmonella typhimurium）季铵化合物外排中的作用，采用红色交换法构建了smvA、acrB和tolC基因突变体。用P22对acrB和smvA突变株进行抗突变试验。通过MIC试验测定了这些菌株对吖啶黄和多种QACs的敏感性，与鼠伤寒沙门氏菌野生型菌株相比，smvA突变株比acrB突变株对QACs更敏感。tolC单突变体比acrB突变体对QAC、吖啶黄、溴化乙锭、孔雀石绿色和派洛宁B更敏感。tolC-acrB双突变体与单tolC突变体一样对QAC敏感。此外，smvA突变株比acrB突变株对吖啶黄更敏感（MIC = 31.3 vs 125 mg/L，即4倍）。最后，tolC-smvA双突变体（3.9 mg/L）对吖啶黄的敏感性比smvA（31.3 mg/L）或tolC（31.3 mg/L）单突变体高约10倍，在来自鼠伤寒沙门氏菌的吖啶黄和其他QAC的外排中起主要作用的是SmvA外排泵，而不是AcrB。这一明显矛盾的报道是由于大肠杆菌中不存在smvA基因。我们的研究结果表明，tolC和smvA基因编码的两个不同的外排系统的组件与重叠的特异性，并行工作，出口吖啶黄素和其他QAC。
The aim was to study the role played by SmvA pump in the efflux of quaternary ammonium compounds (QACs) in Salmonella enterica serovar Typhimurium (Salmonella Typhimurium).Mutants in the smvA, acrB and tolC genes were constructed by the red swap method. P22 was used to transduce tolC to acrB and smvA mutant strains. The susceptibility of these strains to acriflavine and a variety of QACs was determined by MIC assays.In comparison with the Salmonella Typhimurium wild-type strain, the smvA mutant was more susceptible to QACs than the acrB mutant strain. A tolC single mutant was more susceptible than an acrB mutant to QACs, acriflavine, ethidium bromide, malachite green and pyronin B. The tolC-acrB double mutant was as susceptible as the single tolC mutant to QACs. Additionally, the smvA mutant strain was more susceptible to acriflavine than the acrB mutant (MICs = 31.3 versus 125 mg/L, i.e. 4-fold). Finally, the tolC-smvA double mutant (3.9 mg/L) was approximately 10 times more susceptible to acriflavine than either smvA (31.3 mg/L) or tolC (31.3 mg/L) single mutants.It is the SmvA efflux pump, and not AcrB, that plays the major role in the efflux of acriflavine and other QACs from Salmonella Typhimurium. This apparently conflicting report is due to the fact that in Escherichia coli the smvA gene does not exist. Our results suggest that tolC and smvA genes encode components of two different efflux systems with overlapping specificities that work in parallel to export acriflavine and other QACs.