Classic diphtheria is a serious infection that could end terminally without adequate treatment. Cases of diphtheria are registered only sporadically in Western countries. However, the disease is endemic to many other world regions, such as the Far East and East Asia, South America and Africa.
Corynebacteria are Gram-positive, facultative anaerobic, non-sporulating, rod-shaped bacteria that can have tapered or clubbed ends (“coryne”: Greek for club). The majority of representatives of this group are opportunistic pathogens (i.e. only pathogenic under specific conditions). Corynebacterium diphtheriae, the pathogen causing diphtheria, is the most important bacterium of this group. However, only its toxin producing strains can cause diphtheria.