Hans Christian’s gram celebrated his 166th birth anniversary on 13th September 2019. Born on 13th September 1853 and died on 14th November 1938, he was Danish bacteriologist. He was the greatest biologist who invented the gram staining technique that helped in identifying 30000 different species of bacteria. He worked with microbiologist and pathologist Carl Friedlander in Berlin in the early 1880s to investigate and devise the system of bacteria classification. This is known to be the most important staining techniques to identify bacteria under a microscope that has been used in microbiology. He worked as the professor at the University of Copenhagen in 1891 and in 1900 became professor of medicine. He became more popular between 1940 and 1960 when Pierce Gardner professor of medicine at Harvard medical school wrote about Grams stains investigation.

He studied in university of Copenhagen and was a botany assistant (1873-1874) to the zoologist Japetus Steenstrup who studied plants and was later introduced to the pharmacology and use of microscope. He developed interest in the medicine and obtained MD from the University of Copenhagen. Studying red blood cells in men was his first work which enabled him to know that macrocytes were characteristics of pernicious anemia.

In 1884 while working with Carl Friedlander he was successful with the famous staining method known to be Gram staining method. Lung tissue samples were chemically reacted with a substance and depending on the colour change conclusion was derived. The chemical and physical properties of the cell wall differentiated the bacteria’s into gram positive and gram negative.

⦁ Peptidocylan is present in the cell wall of the gram positive cells that retain the colour of the stain – crystal violet and iodine, methylene blue and they appear purple or brown under the microscope.

⦁ Gram negative cells have less or no Peptidocylan that doesn’t allows stain to appear and washes off crystal violet or are red.

The differences between streptococcus pneumonia and klebsiuella pneumonia were found by him.
The first step in identification of a bacterial organism is the gram stain method. Its limitation gives rise to Gram variable and Gram –indeterminate groups.
In 2015, one of the antibiotics Teixobactin was released in the pharmaceutical market which was done with the help of Gram staining method. 50000 types of soil filled with bacteria’s were tested for antibiotics that would kill bugs that caused MRSA and bacteria that cause multi-drug resistant TB. This antibiotic” teixobactin” acted on the “gram-positive “ group of bacteria. If it is used in a proper manner it can be beneficial for the researchers to use it for various bacterial diseases. Some researchers have also argued the staining method that it is not 100 % error free and lacks standardization that is not applicable for all. The same has been warned by Gram in his work published in 1884.
In spite of that this technique has been very useful in saving many lives and performing various tests in the laboratory and is still used in clinical microbiological laboratories for investigation.