Diphteria

Corynebacterium Diphteria

Structure

Gram + bacterium, catalase +, and becomes a group like chinese stick’s. In their cytoplasm there are meta-chromatic granules. This bacterium doesn’t have capsule, movement or spore form. There three types: Gravis, mitis, intermediate and belifante. Normally, a phage infects the cell and integrates the tox+ gene with exotoxin information. This exotoxin goes to bacteria genoma and replicates, after that exotoxin is released to the host cells.

Virulence

Diphteric Toxin: A-B type toxin which B binds to epithelial cells, after is endocytosed and leave the endosome when the Ph is higher. The A portion lick the elongation factor 2 and stops protein synthesis. This toxin is very immunogenic and constitutes the diphtheria vaccine.

Adhesion: Hemaglutinins and fimbriae links to the macrophages via lecithin. Bacterium has a receptor for: N-acetyl glucosamine, N-acetyl galactosamine, galactose, manose, sialic acid. Also has hydrophilic and hydrophobic protein which creates an hydrophobic contact. Lastly, neuroaminidase cut the hemaglutinine-sialic acid contact allowing the bacterium infect more cells.

Syderophores: Bacterium proteins that allow iron caption for protein synthesis.

Transmission: Oral secretions and respiratory secretions, exudates lesions (are more infecting than respiratory secretions). There are normal carriers and can transmit disease only on endemic or epidemic ways. Also with food ingest (e.g. milk).

Pathology

There are two diphtheria types: respiratory and skin diphtheria.

Respiratory: Nasal anterior, oral, larynx. All of those can spread by blood and cause carditis, tubular necrosis and demielinization (which can express as facial muscles deficiency).

Nasal an Oral: Usually express with a white pseudo membrane in nasal septum and tonsils that goes and meets on the oral backside.

Larynx: Regularly is an oral extent that brings edema, nodes and “bull-neck”

Skin: Usually express like skin eruptions with exudates.

Dx: Clinical and mucosa culture.

Treatment: Penicillin and vaccination.