True about corynebacterium diptheria are all except :
“Mechanical complications of diptheria are due to the membrane while the systemic effects are due to the toxin.”

Toxin acts mainly systemically though there are partial local effects.
It has affinity for myocardium, adrenals and nerve endings.
Toxin acts by inactivating EF-2 thus inhibiting protein synthesis.
Toxin production is influenced by iron concentration in the medium. Toxin production is optimal at 0.14 μ g/ ml and is suppressed at 0.5 μ g/ml.
Toxigencity of diptheria bacullus depends on symbiotic bacteriophages so it shows lysogenic or phage

conversion i.e. nontoxigenic strain →→→→→ toxigenic strain by infecting with beta phage.
Remember :

Corynebacteria are gram positive, non acid fast, non sporing, non capsulated, non motile bacteria.
It contains polar bodies or volutin or babes-ernst or metachromatic granules of polymetaphosphate which are more gram positive.
Granules are also stained by loeffler’s methylene blue, Albert’s, Neisser’s and ponder’s stain.
Iron is required for toxin production
Toxin production is responsible for local reaction
Nonsporing, noncapsular and non motile
Toxin production is by lysogenic conversion