Confused and have questions? We’ve got answers. With Chegg Study, you can get step-by-step solutions to your questions from an expert in the field. If you rather get 1:1 study help, try 30 minutes of free online tutoring with Chegg Tutors.

Corynebacterium diphtheria

From Biology-Online Dictionary | Biology-Online Dictionary
Jump to: navigation, search



A non-motile aerobic gram-positive and toxin generating bacterium involved in Diphtheria a deadly disease in human particularly in children.


Corynebacterium diphtheria commonly found in the mouth, nose, throat, skin, body secretion and wounds of infected individuals. It has 69 structural RNA genes in which genome contains 13 pathogenicity islands that codes for fimbrial genes and iron uptake systems producing siderophores and antibiotics.

Corynebacterium diphtheria metabolisms consist of complete pentose phosphate pathway, gluconeogenesis and glycolysis based on the enzyme present in the cell. It is aerobic wherein production of purines is complete whereas pyrimidines lacks cytidine production pathway. It also formed thick gray-green fibrin membrane on the sites of infections due to the bacterial growth, necrosis of underlying tissue and toxin production.

Corynebacterium diphtheria infects nasopharynx in which toxigenic strains secretes effective exotoxin that cause diphtheria manifested withfever, pharyngitis, swelling of the neck and skin lesion wherein toxin is dispersed to the distant organs by the circulatory system causing paralysis and heart failure. A diphtherial infection is complicated due to its toxigenicity factors in which concentration of extracellular inorganic iron is low and presence of bacterial chromosome of a lysogenic prophage containing tox gene.

Scientific classification:

Domain: Bacteria
Phylum: Actinobacteria
Order: Actinomycetales
Family: Corynebacteriaceae
Genus: Corynebacterium
Species: Corynebacterium diphtheria

See also: