Beggs W H, Andrews F A
J Infect Dis. 1976 Nov;134(5):500-4. doi: 10.1093/infdis/134.5.500.
Studies were designed to determine whether ionic strength (mu) is a significant factor in salt inhibition of aminoglycoside action against Escherichia coli and Pseudomonas aeruginosa. In both nutrient broth (a low mu medium) and Mueller-Hinton broth (a relatively high mu medium), protection of E. coli from dihydrostreptomycin or gentamicin action by MgCl2, NaCl, or Na2SO4 was attributed to ionic strength alone. The percentage of protection increased with ionic strength and was independent of the particular salt used. Antagonism of aminoglycoside action against P. aeruginosa appeared to involve both a specific, divalent caption-dependent mechanism, revealed in Mueller-Hinton broth, and a nonspecific, ionic strength effect, elicited by sodium salts in nutrient broth. With media of relatively low salt content, variation in ionic strength itself over a range of mu of 0.02-0.14 significantly influences the effectiveness of aminoglycoside antibiotics against E. coli and P. aeruginosa.
开展了多项研究以确定离子强度（μ）是否是盐抑制氨基糖苷类药物对大肠杆菌和铜绿假单胞菌作用的一个重要因素。在营养肉汤（一种低μ培养基）和穆勒-欣顿肉汤（一种相对高μ培养基）中，MgCl₂、NaCl或Na₂SO₄对大肠杆菌免受二氢链霉素或庆大霉素作用的保护作用仅归因于离子强度。保护百分比随离子强度增加而增加，且与所使用的特定盐无关。氨基糖苷类药物对铜绿假单胞菌作用的拮抗似乎涉及两种机制，一种是在穆勒-欣顿肉汤中揭示的特定的、依赖二价阳离子的机制，另一种是营养肉汤中钠盐引发的非特异性离子强度效应。在盐含量相对较低的培养基中，离子强度本身在0.02 - 0.14的μ范围内变化会显著影响氨基糖苷类抗生素对大肠杆菌和铜绿假单胞菌的有效性。
