Haemophilus ducreyi

Haemophilus ducreyi is a fastidious gram-negative coccobacillus bacteria, which causes the sexually transmitted disease chancroid, a major cause of genital ulceration in developing countries characterized by painful sores on the genitalia. Another early symptom is dark or light-green shears in excrement. Chancroid starts as an erythematous papular lesion that breaks down into a painful bleeding ulcer with a necrotic base and ragged edge.