The biologist who helped investigate bacteria

Hans Christian Gram, the inventor of the Gram staining technique, was a pioneering biologist who devised the system of classification which led to as many as 30,000 formally named species of micro organism being investigated. He’s the subject of the cutting-edge Google doodle, created to honour his birth date of 13 September 1853. Gram, working with German pathologist and microbiologist Carl Friedlander, devised the technique in Berlin in the early 1880s. It is still recognized as one of the most essential staining techniques used in microbiology to pick out micro organism beneath a microscope.

Gram first dripped reagents, a substance designed to cause a chemical reaction, onto lung tissue samples. He located variations in the colouring of micro organism that is now regarded to be Streptococcus pneumoniae and Klebsiella pneumoniae. The variations Gram located are a end result of the composition of the bacterial cell wall. Some bacteria have a cellphone wall composed of peptidoglycan, a polymer of sugar and amino acids. These “gram-positive” bacterial cells continue the shade of a stain – usually a complex of crystal violet and iodine, or methylene blue – and appear purple or brown underneath the microscope. Others, that do no longer include peptidoglycan, are now not stained and are referred to as gram-negative, and show up red.

Its reputation peaked between 1940 and 1960. Pierce Gardner, an companion professor of remedy at Harvard Medical School, wrote about the Gram stain and its interpretation in 1974: “It is our feeling that the Gram-stained smear need to be viewed part of the physical examination of the affected person with an acute bacterial infection and belongs in the repertoire of all physicians delivering principal care in acutely sick patients.”

More recently, Gram staining has been used to help become aware of new antibiotics, which are key in the conflict against antimicrobial resistance. Teixobactin – one of two new antibiotics launched to the pharmaceutical market in 2015 – was once recognized through employing a new twist on a tried and tested method of screening soil for micro organism that have advanced to kill their competitors.

A crew at Northwestern University in Boston, Massachusetts screened 50,000 kinds of soil-dwelling micro organism for antibiotics that killed bugs like the hospital acquired contamination MRSA and the bacteria that cause multi-drug resistant TB.

The staining technique was once important as the screen recognized teixobactin, which looks to act on the “gram-positive” crew of micro organism via targeting a lipid on their phone walls, along with other molecules. If used correctly, the researchers in the back of the discovery of teixobactin could be a manageable cure choice for bacterial diseases – and safe from the risk of resistance – for at least 30 years.

While differentiating bacteria into either gram-positive or -negative is critical to most bacterial identification systems, researchers have argued the Gram staining approach is prone to error and “is poorly controlled and lacks standardisation” – some thing Gram himself warned of when his work used to be posted in 1884

“I have published the method, although I am conscious that as yet it is very defective and imperfect,” he noted. “But it is hoped that in the fingers of other investigators it will turn out to be useful.”

The problems with Gram’s method have led to a search for different tests, and numerous picks that claim to be upgrades on it have appeared in the literature. Nonetheless, the Gram stain remains one of the most oftentimes performed assessments in the clinical microbiology laboratory, and a foundational method in treating bacterial infections and saving lives.