Haemophilus ducreyi

Haemophilus ducreyi is a fastidious gram-negative coccobacillus causing the sexually transmitted disease chancroid, a major cause of genital ulceration in developing countries characterized by painful sores on the genitalia.

Early symptoms are dark and light green shears in excrement. Chancroid starts as an erythematous popular lesion that breaks down into a painful bleeding ulcer. It can be cultured on chocolate agar.

It is an opportunistic microorganism that infects through the skin or epidermis. When lymphocytes, macrophages, and granulocytes flood the area of infection inflammation occurs. Pyrogenic inflammation causes regional lymphadenitis in sexually transmitted bacillus chancroid.