Gram Staining

Specific bacterial organisms were first proved by experts and scientists to be the cause of certain diseases in the second half of 1900’s. During the said century, the microscope was further developed yet and experts were keen in identifying the bacteria, as well as in classifying and defining it with the helpful use of the compound microscope. Later on, the compound binocular microscope was also developed, in which it also has the same function as the first one mentioned, but only features two eyepiece for more convenient use, because both eyes can be used in viewing specimens under it for the purpose of eye strain prevention. A variety of different dyes were used to stain cells to identify various organisms, such as the bacteria. Scientist had developed certain methods to stain cells to aid their study and used natural substance, like saffron which stained some parts of the cells on the late eighteenth century. The discovery of synthetic dyes in mid-1800’s helped scientists to use more colors in staining cells, and effectively use the compound binocular microscope to identify the bacteria in a cell.

Hans Christian Joachim Gram, a Danish physician developed staining bacteria method in the late 1800’s. The said method was originally developed by Paul Ehrlich, a German biologist, in which he used gentian violet, also known as cationic dye and aniline water as well in staining cells, the result was well-responsive as seen under the compound microscope, for which the cell walls appeared violet after the method was applied. For further research of Gram in such method of Ehrlich’s, he added a few solution of potassium triiodide as a mordant for the gentian violet, the cells then were also poured ethanol as an addition to his experiment for the purpose of washing away the unfixed dye. Gram then discovered in the microscopy that some cells remained violet, while the color of the others faded away. He diagnosed the result to have positive and negative results, in which those that stayed violet were “positive”, and vice versa.

Another method of staining has been added by Carl Weigert, director of Seckenberg foundation in Frankfurt Germany. Weigert did the same method as of Gram’s except for his final staining procedure, wherein he used saffranine or an anionic dye, in which the result is definitive, meaning- the Gram negative bacteria would appear red and the Gram positive would appear violet when viewed either in a compound binocular microscope or in a compound microscope alone.

Features on how to distinguish Gram positive and negative bacteria from each other when viewed using the compound binocular microscope is clearly seen in the cell wall structures in which certain staining results are identified to be either a positive or negative bacteria.

For bacteria, to know if it is Gram positive or negative is necessary for which a certain drug may be used for treatment because there are a lot of various drugs to be used but each of them are reactants to a certain Gram positive or negative bacteria. The Gram-staining method is also reported to be useful in the development of the new antibacterial drugs in which experts and scientists use the said method to know and discover the effectiveness of the certain drug. Read more