School of Pharmacy and Life Sciences, Research Institute for Health and Welfare, Robert Gordon University, Schoolhill, Aberdeen, AB10 1FR, UK,
Curr Microbiol. 2014 Jan;68(1):6-11. doi: 10.1007/s00284-013-0433-3. Epub 2013 Aug 9.
The membrane-active antimicrobial agent chlorhexidine is used extensively as an antiseptic during infection prophylaxis and treatment. Whilst known to induce membrane damage that results in loss of internal solutes from bacteria, the present study sought to determine the rate and extent of cytoplasmic potassium loss and whether any species-specific differences exist. Direct measurement of potassium was achieved using flame emission spectrophotometry. Exposure of selected species to minimum inhibitory (MIC) or minimum bactericidal concentration (MBC) resulted in solute loss that was both concentration and time dependent. Within 5-min treatment with MIC levels, losses of 3 % from P. aeruginosa, 9 % from E. coli, and 15 % from S. aureus were recorded, whilst at 5 % w/v chlorhexidine, elevated loss of 20, 28, and 41 % occurred, respectively. Nonlinear potassium release was evident from all species when treated with 5 % chlorhexidine over a 60-min period. After this contact time, potassium loss from E. coli and S. aureus rose to 93 or 90 %, respectively; in contrast, P. aeruginosa retained 62 % intracellular potassium. Results confirm lethal concentrations of chlorhexidine induce rapid and substantial loss of cytoplasmic potassium from common pathogens. However, bacterial responses vary between species and should be borne in mind when considering mechanism of action.
膜活性抗菌剂洗必泰被广泛用作感染预防和治疗中的防腐剂。尽管已知洗必泰会导致膜损伤，从而导致细菌内部溶质的损失，但本研究旨在确定细胞质钾损失的速度和程度，以及是否存在任何特定于物种的差异。使用火焰发射分光光度法直接测量钾。将选定的物种暴露于最小抑菌浓度（MIC）或最小杀菌浓度（MBC）下，导致溶质损失既与浓度有关，也与时间有关。在 MIC 水平下处理 5 分钟，铜绿假单胞菌损失 3%，大肠杆菌损失 9%，金黄色葡萄球菌损失 15%，而在 5% w/v 洗必泰下，分别出现 20%、28%和 41%的高损失。当用 5%洗必泰处理所有物种 60 分钟时，都可以明显看出钾的非线性释放。经过这段接触时间，大肠杆菌和金黄色葡萄球菌的钾损失分别上升到 93%或 90%；相比之下，铜绿假单胞菌保留了 62%的细胞内钾。结果证实，洗必泰的致死浓度会导致常见病原体的细胞质钾迅速大量损失。然而，不同物种之间的细菌反应存在差异，在考虑作用机制时应加以注意。
