Corynebacterium diphtheriae is a pathogenic bacterium that causes diphtheria

Diphtheria

Diphtheria is an upper respiratory tract illness caused by Corynebacterium diphtheriae, a facultative anaerobic, Gram-positive bacterium. It is characterized by sore throat, low fever, and an adherent membrane on the tonsils, pharynx, and/or nasal cavity...

. It is also known as the Klebs-Löffler bacillus, because it was discovered in 1884 by German

Germany

Germany , officially the Federal Republic of Germany , is a federal parliamentary republic in Europe. The country consists of 16 states while the capital and largest city is Berlin. Germany covers an area of 357,021 km2 and has a largely temperate seasonal climate...

 bacteriologists

Bacteriology

Bacteriology is the study of bacteria. This subdivision of microbiology involves the identification, classification, and characterization of bacterial species...

 Edwin Klebs

Edwin Klebs

Theodor Albrecht Edwin Klebs was a German-Swiss pathologist. He is mainly known for his work on infectious diseases. He is the father of Arnold Klebs.-Life:...

 (1834 – 1912) and Friedrich Löffler

Friedrich Löffler

-External links:* German Federal Research Institute for Animal Health...

 (1852 – 1915).
Four subspecies are recognized: C. diphtheriae mitis, C. diphtheriae intermedius, C. diphtheriae gravis, and C. diphtheriae belfanti. The four subspecies differ slightly in their colonial morphology and biochemical properties, such as the ability to metabolize certain nutrients, but all may be toxigenic (and therefore cause diphtheria) or non-toxigenic.