Haemophilus ducreyi

Haemophilus ducreyi is a gram-negative, facultatively anaerobic rod in chains. It is the cause of a soft ulcer (ulcus molle) on the genitals. It is a strictly human pathogen.

Cultivation
Cultivation of hemophilia is generally demanding, requiring soils enriched with growth factors. H. ducreyi grows in the presence of factor X (hemin). Colonies are visible after 2-9 days.

Diagnostics
Microscopy of material from the ulcer or aspirate from the affected lymph nodes shows G− rods in chains inside and outside the polymorphonuclear cells. The painting is often described as a "school of fish". Rich soils (eg chocolate agar) and CO2 atmosphere are used in the cultivation, a yolk bag of chicken embryos can also be used. In an experiment on an animal (rabbit), ulceration occurs after injection of a pure culture.

An indirect evidence is the so-called Ducrey test, in which inactivated hemophiles are applied subcutaneously. A positive test will show a local inflammatory reaction.

Treatment
Macrolides (azithromycin) and cephalosporins (ceftriaxone) are used for therapy.

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Source

 * ws:Haemophilus ducreyi