外排泵和环境 pH 在细菌多重耐药性中的作用。
The Role of Efflux Pumps and Environmental pH in Bacterial Multidrug Resistance.
机构信息
Department of Medical Microbiology and Immunobiology, Faculty of Medicine, University of Szeged, Szeged, Hungary.
Travel Medicine, Institute of Hygiene and Tropical Medicine, Universidade Nova de Lisboa, Lisbon, Portugal.
出版信息
In Vivo. 2020 Jan-Feb;34(1):65-71. doi: 10.21873/invivo.11746.
BACKGROUND/AIM: One of the most studied bacterial resistance mechanisms is the resistance related to multidrug efflux pumps. In our study the pump activity of the Escherichia coli K-12 AG100 strain expressing the AcrAB-TolC pump system was investigated at pH 7 and pH 5 in the presence of the efflux pump inhibitor (EPI) promethazine (PMZ).
MATERIALS AND METHODS
The EPI activity was assessed by real-time fluorimetry. The influence of PMZ treatment on the relative expression of the pump genes acrA, acrB and their regulators marA, marB, marR, the stress genes soxS, rob, as well as the bacterial growth control genes ftsI, and sdiA were determined by RT-qPCR.
RESULTS
The EPI activity of PMZ was more effective at neutral pH. The PMZ treatment induced a significant stress response in the bacterium at acidic pH by the up-regulation of genes.
CONCLUSION
The genetic system that regulates the activity of the main efflux pump is pH-dependent.
背景/目的：研究最多的细菌耐药机制之一是与多药外排泵相关的耐药性。在本研究中，在 pH 值为 7 和 pH 值为 5 的条件下，研究了表达 AcrAB-TolC 泵系统的大肠杆菌 K-12 AG100 菌株的泵活性，并检测了外排泵抑制剂（EPI）异丙嗪（PMZ）的作用。
材料和方法
通过实时荧光法评估 EPI 活性。通过 RT-qPCR 确定 PMZ 处理对泵基因 acrA、acrB 及其调节剂 marA、marB、marR、应激基因 soxS、rob 以及细菌生长控制基因 ftsI 和 sdiA 的相对表达的影响。
结果
EPI 的 PMZ 活性在中性 pH 值下更为有效。在酸性 pH 值下，PMZ 处理通过上调基因诱导细菌产生显著的应激反应。
结论
调节主要外排泵活性的遗传系统依赖于 pH 值。
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