Antibacterial silver.
Antibacterial silver.
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抗菌银。
DOI：
10.1155/mbd.1994.467
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发表时间：
1994
期刊：
影响因子：
--
通讯作者：
Jarrett PS
中科院分区：
文献类型：
--
作者：
Clement JL;Jarrett PS
银的抗菌活性早已为人所知，并且已经发现了多种应用，因为它对人体细胞的毒性比对细菌的毒性低得多。 最广泛记录的用途是预防性治疗烧伤和水消毒。然而，银杀死细胞的机制尚不清楚。关于耐药机制的信息显然是矛盾的，甚至在这样的系统中的Ag+的化学也知之甚少。银与许多细胞成分结合，其中膜成分可能比核酸更重要。很难知道强结合是否反映毒性或解毒：据报道，一些敏感的细菌菌株比相应的耐药菌株积累更多的银，在其他情况下，显然发生相反的情况。在一些情况下，耐药性已被证明是质粒介导的。据报道，质粒很难转移，也很难维持，正如我们所发现的那样，试图找到耐药菌株和敏感菌株之间的生化差异的努力取得了有限的成功：差异是微妙的，例如耐药大肠杆菌的细胞表面疏水性增加。有些问题是由于可以观察到阻力的限定条件造成的。已显示银（I）与细胞培养基的组分结合，并且氯化物的存在对于证明耐药性是必要的。还必须考虑所用银的形式。这通常是水溶性的AgNO3，它很容易沉淀为AgCl。临床上优选的化合物是高度不溶性的磺胺嘧啶银，其在烧伤时不会引起低氯血症。有人认为，耐药细菌是那些不能比氯离子更紧密地结合Ag+的细菌。可能是某些形式的不溶性银被细胞吸收了，正如镍所发现的那样。在我们的实验条件下，与某些配体络合的银比AgNO3更具有细胞毒性，而与相关配体络合的银的毒性要小得多。显然，溶解度和稳定性之间存在微妙的相互作用，这应该值得进一步研究。
The antibacterial activity of silver has long been known and has found a variety of applications because its toxicity to human cells is considerably lower than to bacteria. The most widely documented uses are prophylactic treatment of burns and water disinfection. However, the mechanisms by which silver kills cells are not known. Information on resistance mechanisms is apparently contradictory and even the chemistry of Ag+ in such systems is poorly understood. Silver binds to many cellular components, with membrane components probably being more important than nucleic acids. It is difficult to know whether strong binding reflects toxicity or detoxification: some sensitive bacterial strains have been reported as accumulating more silver than the corresponding resistant strain, in others the reverse apparently occurs. In several cases resistance has been shown to be plasmid mediated. The plasmids are reported as difficult to transfer, and can also be difficult to maintain, as we too have found. Attempts to find biochemical differences between resistant and sensitive strains have met with limited success: differences are subtle, such as increased cell surface hydrophobicity in a resistant Escherichia coli. Some of the problems are due to defining conditions in which resistance can be observed. Silver(I) has been shown to bind to components of cell culture media, and the presence of chloride is necessary to demonstrate resistance. The form of silver used must also be considered. This is usually water soluble AgNO3, which readily precipitates as AgCl. The clinically preferred compound is the highly insoluble silver sulfadiazine, which does not cause hypochloraemia in burns. It has been suggested that resistant bacteria are those unable to bind Ag+ more tightly than does chloride. It may be that certain forms of insoluble silver are taken up by cells, as has been found for nickel. Under our experimental conditions, silver complexed by certain ligands is more cytotoxic than AgNO3, yet with related ligands is considerably less toxic. There is evidently a subtle interplay of solubility and stability which should reward further investigation.