Adams E
Stain Technol. 1975 Jul;50(4):227-31. doi: 10.3109/10520297509117063.
Gram-negative bacteria stained with crystal violet are decolorized by 95% alcohol within 2 min, whereas Gram-positive bacteria require at least 3 min treatment. Aqueous solutions of safranin, neutral red, and fuschsin replace crystal violet from stained Gram-positive bacteria more quickly than alcohol alone, and alcoholic solutions of these counterstains are in most cases still more effective. Treatment of crystal violet-stained organisms with alcoholic safranin (0.25%) for 15 sec will distinguish Gram-positive bacteria (violet) from Gram-negative bacteria (pink). Alcohol containing very low concentrations of iodine generally decolorizes crystal violet-stained Gram-positive bacteria more quickly than alcohol alone. Increasing concentrations of iodine in alcohol reduce the rate of decolorization of stained bacteria, but stained Gram-negative bacteria are still readily decolorized. The addition of 0.1% iodine to alcohol increases the rate of extraction of crystal violet by alcohol from Gram-negative organisms, but delays extraction of dye from Gram-positive organisms, and this applies when counterstain is also present. A two-solution modification of Gram staining is described in which crystal violet-stained bacteria are treated with an alcoholic solution of safranin, fuchsin, and iodine.
用结晶紫染色的革兰氏阴性菌在2分钟内会被95%的酒精脱色，而革兰氏阳性菌则需要至少3分钟的处理时间。番红、中性红和品红的水溶液比单独的酒精能更快地从染色的革兰氏阳性菌中取代结晶紫，并且这些复染剂的酒精溶液在大多数情况下仍然更有效。用酒精番红（0.25%）处理结晶紫染色的生物体15秒，可区分革兰氏阳性菌（紫色）和革兰氏阴性菌（粉红色）。含碘量极低的酒精通常比单独的酒精能更快地使结晶紫染色的革兰氏阳性菌脱色。酒精中碘浓度的增加会降低染色细菌的脱色速率，但染色的革兰氏阴性菌仍很容易脱色。向酒精中添加0.1%的碘会增加酒精从革兰氏阴性生物体中提取结晶紫的速率，但会延迟从革兰氏阳性生物体中提取染料的时间，当存在复染剂时也是如此。本文描述了革兰氏染色的一种双溶液改良方法，即用番红、品红和碘的酒精溶液处理结晶紫染色的细菌。
