Löffler's medium is a special substance used to grow

diphtheria Diphtheria is an infection caused by the bacterium '' Corynebacterium diphtheriae''. Most infections are asymptomatic or have a mild clinical course, but in some outbreaks more than 10% of those diagnosed with the disease may die. Signs and s ...

bacilli Bacilli is a taxonomic class of bacteria that includes two orders, Bacillales and Lactobacillales, which contain several well-known pathogens such as ''Bacillus anthracis'' (the cause of anthrax). ''Bacilli'' are almost exclusively gram-positive ...

to confirm the diagnosis.

History

In 1887,

Friedrich Loeffler Friedrich August Johannes Loeffler (; 24 June 18529 April 1915) was a German bacteriologist at the University of Greifswald. Biography He obtained his M.D. degree from the University of Berlin in 1874. He worked with Robert Koch from 1879 to 1884I ...

devised a culture medium containing horse serum, meat infusion, and dextrose for use in the cultivation of

corynebacteria ''Corynebacterium'' () is a genus of Gram-positive bacteria and most are aerobic. They are bacilli (rod-shaped), and in some phases of life they are, more specifically, club-shaped, which inspired the genus name (''coryneform'' means "club-shape ...

and for differentiating them from other organisms. Perry and Petran suggested modification of the original formulation. Buck, in 1949, described a modified Loeffler's medium for cultivating ''

Corynebacterium diphtheriae ''Corynebacterium diphtheriae'' is the pathogenic bacterium that causes diphtheria. It is also known as the Klebs–Löffler bacillus, because it was discovered in 1884 by German bacteriologists Edwin Klebs (1834–1912) and Friedrich Löffl ...

''.

Uses

This medium has a variety of uses in microbiological investigations. The current formulation incorporated these later modifications: # The primary value of Loeffler medium is in the growth and morphological characterization of members of the genus'' Corynebacterium''. This formulation enhances the formation of metachromatic granules within the cells of the organisms. # Due to its serum content, Loeffler medium can be used for the determination of proteolytic activities of microorganisms. # The gray-white surface of the medium provides an excellent background for the detection and observation of colonial pigmentation. # If all extraneous moisture is removed aseptically from the slants and the upper part of the slant is heated until the slant ruptures, this medium can be used for the detection of ascospores.

Principles of the procedure

Heart muscle and animal tissue peptone provide the

amino acid Amino acids are organic compounds that contain both amino and carboxylic acid functional groups. Although hundreds of amino acids exist in nature, by far the most important are the alpha-amino acids, which comprise proteins. Only 22 alpha am ...

s and other complex nitrogenous substances necessary to support growth of corynebacteria.

Sodium chloride Sodium chloride , commonly known as salt (although sea salt also contains other chemical salts), is an ionic compound with the chemical formula NaCl, representing a 1:1 ratio of sodium and chloride ions. With molar masses of 22.99 and 35.45 g ...

supplies essential ions.

Dextrose Glucose is a simple sugar with the molecular formula . Glucose is overall the most abundant monosaccharide, a subcategory of carbohydrates. Glucose is mainly made by plants and most algae during photosynthesis from water and carbon dioxide, using ...

is a source of fermentable

carbohydrate In organic chemistry, a carbohydrate () is a biomolecule consisting of carbon (C), hydrogen (H) and oxygen (O) atoms, usually with a hydrogen–oxygen atom ratio of 2:1 (as in water) and thus with the empirical formula (where ''m'' may or ma ...

. The eggs and beef serum cause the medium to coagulate during the sterilization process and are sources of

protein Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, respo ...

which are used for metabolism of the corynebacteria and other organisms.

References

{{DEFAULTSORT:Loffler's medium Microbiology techniques Microbiological media Diphtheria 1887 in science 1887 in Germany