Löffler's medium is a special substance used to grow

diphtheria Diphtheria is an infection caused by the bacteria, bacterium ''Corynebacterium diphtheriae''. Most infections are asymptomatic or have a mild Course (medicine), clinical course, but in some outbreaks, the mortality rate approaches 10%. Signs a ...

bacilli Bacilli is a Taxonomy (biology), taxonomic Class (biology), 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'' ...

to confirm the diagnosis.

History

In 1887, Friedrich Loeffler devised a culture medium containing horse serum, meat infusion, and dextrose for use in the cultivation of corynebacteria 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 a Gram-positive 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 ...

''.

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 over 500 amino acids exist in nature, by far the most important are the 22 α-amino acids incorporated into proteins. Only these 22 a ...

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

Sodium chloride Sodium chloride , commonly known as Salt#Edible salt, edible salt, is an ionic compound with the chemical formula NaCl, representing a 1:1 ratio of sodium and chloride ions. It is transparent or translucent, brittle, hygroscopic, and occurs a ...

supplies essential ions.

Dextrose Glucose is a sugar with the molecular formula , which is often abbreviated as Glc. It is overall the most abundant monosaccharide, a subcategory of carbohydrates. It is mainly made by plants and most algae during photosynthesis from water an ...

is a source of fermentable

carbohydrate A carbohydrate () is a biomolecule composed of carbon (C), hydrogen (H), and oxygen (O) atoms. The typical hydrogen-to-oxygen atomic ratio is 2:1, analogous to that of water, and is represented by the empirical formula (where ''m'' and ''n'' ...

. 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 residue (biochemistry), residues. Proteins perform a vast array of functions within organisms, including Enzyme catalysis, catalysing metab ...

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