Who was Hans Christian Gram and what did the groundbreaking scientist discover?

From Clémence Michallon, published at Fri Sep 13 2019

Influential scientist Hans Christian Gram left a durable mark on microbiology thanks to the pioneering staining technique he invented – and he’s now being celebrated with a Google Doodle on the 166th anniversary of his birth.

Born on 13 September, 1853, Gram earned his MD from the University of Copenhagen before working as a resident physician in the city’s municipal hospital.

He then travelled around Europe while expending his expertise bacteriology and pharmacology.

It was while working in the Berlin laboratory of microbiologist Karl Friedländer that Gram developed the “Gram stain”, a scientific method used to identify and characterise bacteria, as noted by the Encyclopaedia Britannica.

The Gram stain method – named after its inventor – consists in treating a smear of bacteria with a violet dye, then rinsing it with iodine solution and an organic solvent.

Bacteria with a thick cell wall remain purple and are called Gram-positive.

Bacteria with a thinner cell wall, on the other hand, do not retain the stain and are called Gram-negative.

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Gram retired in 1923 and died in 1938 at 85 years old.

The Gram method remains widely used eight decades after his death, cementing his legacy in the world of microbiology.