The toxigenicity of C.diphtheriae is due to:
The toxigenicity of C.diphtheriae is due to beta phage. Diphtheria Toxin production depends on : Phage coded: Diphtheria Toxin is coded by b corynephage carrying tox gene-toxigenic. Iron concentration: toxin production depends on optimum iron concentration (0.1 mg per liter). DT repressor gene (DtxR)- iron dependent negative regulator of Diphtheria Toxin production and iron uptake in C.diphtheriae. Biotypes: 3 biotypes with their toxigenicity is as follows : All strains of gravis, 95-99% strains of intermedius, 80-85% of mitis strains are toxigenic. However, toxins produced by different biotypes are antigenically similar.
Systemic Bacteriology (Gram Positive Bacilli, Gram Negative Bacilli)
Beta phage
Lambda page
Gamma phage
Delta phage
Beta phage