In which of the following is bacteraemia LEAST likely to occur?

Bacteraemia is least likely to occur in:

c. Diphtheria

Diphtheria is primarily a local infection with the bacteria Corynebacterium diphtheriae, and while it can cause systemic effects due to toxin production, it does not typically result in bacteraemia. In contrast, the other conditions listed are associated with higher rates of bacteraemia.