Hans Gram developed a microbiological technique which is still used today in clinical microbiology practice and bacteriology in particular for microbial identification and classification. His technique is generally used in microbiology for differentiating and classifying bacteria into two major types based on their reaction to certain stains or dye.
The technique he developed is called Gram staining technique; and it is used to distinguish bacteria into Gram positive bacteria or Gram negative bacteria depending on the cell wall of the bacteria and on their reaction to crystal violet dye (the primary stain retained by Gram positive bacteria) and safranin dye (the counter stain retained by Gram negative bacteria) respectively.
Hans Gram was a Danish bacteriologist and a physician; and his discovery of Gram staining technique was timely, and a procedure which is one of the most widely used protocol in medical microbiology.
Gram staining technique is one of the most applied physiological-biochemical staining technique which is very practical in the detection and differentiation of bacteria. Though not all bacteria can be typed by the Gram staining technique (e.g. Mycobacterium, Chlamydia, Mycoplasma, Rickettsia, Treponema and Borrelia), the Gram reaction is still very relevant in the practice of microbiology worldwide.
Barrett J.T (1998). Microbiology and Immunology Concepts. Philadelphia, PA: Lippincott-Raven Publishers. USA.
Beck R.W (2000). A chronology of microbiology in historical context. Washington, D.C.: ASM Press.
Chung K.T, Stevens Jr., S.E and Ferris D.H (1995). A chronology of events and pioneers of microbiology. SIM News, 45(1):3–13.
Nester E.W, Anderson D.G, Roberts C.E and Nester M.T (2009). Microbiology: A Human Perspective. Sixth edition. McGraw-Hill Companies, Inc, New York, USA.
Salyers A.A and Whitt D.D (2001). Microbiology: diversity, disease, and the environment. Fitzgerald Science Press Inc. Maryland, USA.
Slonczewski J.L, Foster J.W and Gillen K.M (2011). Microbiology: An Evolving Science. Second edition. W.W. Norton and Company, Inc, New York, USA.
Summers W.C (2000). History of microbiology. In Encyclopedia of microbiology, vol. 2, J. Lederberg, editor, 677–97. San Diego: Academic Press.
Wainwright M (2003). An Alternative View of the Early History of Microbiology. Advances in applied microbiology. Advances in Applied Microbiology, 52:333–355.