Regulation of the Two-Component Regulator CpxR on Aminoglycosides and β-lactams Resistance in Salmonella enterica serovar Typhimurium.
Regulation of the Two-Component Regulator CpxR on Aminoglycosides and β-lactams Resistance in Salmonella enterica serovar Typhimurium.
复制标题
双组分调节剂 CpxR 对鼠伤寒沙门氏菌氨基糖苷类和 β-内酰胺类耐药性的调节
DOI：
10.3389/fmicb.2016.00604
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发表时间：
2016
影响因子：
5.2
通讯作者：
Hu G
中科院分区：
文献类型：
--
作者：
Huang H;Sun Y;Yuan L;Pan Y;Gao Y;Ma C;Hu G
双组分信号转导系统CpxAR在革兰氏阴性菌中尤其普遍。有报道称，CpxAR参与了大肠杆菌的多药耐药(MDR)。CpxR是双分量CpxAR系统中的响应调节器。本研究的目的是探讨cpxR在鼠伤寒沙门氏菌多药耐药中的作用。用二倍稀释法测定了兽医常用抗生素对JS(鼠伤寒沙门氏菌多药敏感标准株)、JSΔcpxR、JSΔcpxR/pcpxR、JSΔcpxR/pcpxR*、JSΔcpxRΔAcrB、JSΔcpxRΔacrB/pcpxR、JSΔcpxRΔAcrB/pcpxR*、9株伤寒沙门氏菌分离株(SH1-9)和SH1-9ΔcpxR的最低抑菌浓度(MIC)。实时荧光定量聚合酶链式反应检测JS、JSΔcpxR和JSΔcpxR/pcpxR株OmpF、OMPC、ompW、ompD、tolC、acrB、acrd、acrf、mda、marA和soxs基因的相对表达水平。结果表明，JSΔcpxR菌株对阿米卡星(AMK)、庆大霉素(GEN)、安普霉素(APR)、新霉素(NEO)、头孢曲松(CRO)、头孢硫呋喃(CEF)和头孢喹酮(CEQ)的MIC较亲本菌株JS降低2~4倍。与亲本株SH1-9相比，除NEO外，SH1-9ΔcpxR对上述抗生素的耐药率降低了2~8倍。此外，JSΔcpxRΔAcrB株对AMK、GEN、APR和CEF的MIC值比JSΔAcrB株进一步降低了2~4倍。此外，在JSΔ中，CpxR的过量表达导致ompF、ompPC、ompW、ompD、tolC、acrB、marA和soxs的基因表达水平显著降低，而stm3031和stm1530的基因表达水平显著升高。值得注意的是，在以亚抑制浓度同时诱导所有菌株至第15代后，JSΔcpxR/pc pxR菌株与JSΔcpxR菌株相比，外排泵ACRD和MDTA基因的表达水平显著增加。我们的结果表明，双组分调节剂CpxR通过影响多药耐药相关基因的表达水平而参与了鼠伤寒沙门氏菌对氨基糖苷类和β-内酰胺类抗生素的耐药性。
The two-component signal transduction system CpxAR is especially widespread in Gram-negative bacteria. It has been reported that CpxAR contributes to the multidrug resistance (MDR) in Escherichia coli. CpxR is a response regulator in the two-component CpxAR system. The aim of this study was to explore the role of cpxR in the MDR of S. enterica serovar Typhimurium. The minimal inhibitory concentrations (MICs) of various antibiotics commonly used in veterinary medicine for strains JS (a multidrug-susceptible standard strain of S. enterica serovar Typhimurium), JSΔcpxR, JSΔcpxR/pcpxR, JSΔcpxR/pcpxR*, JSΔcpxRΔacrB, JSΔcpxRΔacrB/pcpxR, JSΔcpxRΔacrB/pcpxR*, 9 S. enterica serovar Typhimurium isolates (SH1–9), and SH1–9ΔcpxR were determined by the 2-fold broth microdilution method. The relative mRNA expression levels of ompF, ompC, ompW, ompD, tolC, acrB, acrD, acrF, mdtA, marA, and soxS in strains JS, JSΔcpxR, and JSΔcpxR/pcpxR were detected by real-time PCR. The results showed 2- to 4-fold decreases in the MICs of amikacin (AMK), gentamycin (GEN), apramycin (APR), neomycin (NEO), ceftriaxone (CRO), ceftiofur (CEF), and cefquinome (CEQ) for strain JSΔcpxR, as compared to those for the parental strain JS. Likewise, SH1–9ΔcpxR were found to have 2- to 8-fold reduction in resistance to the above antibiotics, except for NEO, as compared to their parental strains SH1–9. Furthermore, 2- to 4-fold further decreases in the MICs of AMK, GEN, APR, and CEF for strain JSΔcpxRΔacrB were observed, as compared to those for strain JSΔacrB. In addition, CpxR overproduction in strain JSΔcpxR led to significant decreases in the mRNA expression levels of ompF, ompC, ompW, ompD, tolC, acrB, marA, and soxS, and significant increases in those of stm3031 and stm1530. Notably, after all strains were induced simultaneously by GEN to the 15th passage at subinhibitory concentrations, strain JSΔcpxR/pcpxR showed significant increases in mRNA expression levels of the efflux pump acrD and mdtA genes, as compared to strain JSΔcpxR. Our results indicate that the two-component regulator CpxR contributes to resistance of S. enterica serovar Typhimurium to aminoglycosides and β-lactams by influencing the expression level of the MDR-related genes.