Prevotella melaninogenica in the vagina

Generally found in the mouth, opportunistic pathogen in humans. Produces black pigment when grown on blood-containing media, which can be seen in quickly progressing gum lesions^​1​.

Acidic microbe (liquefies gelatin and clots milk).

Normal flora of the upper respiratory tract in humans (lungs, nose). Often mixes with anaerobic infections with aerobic and anaerobic colleagues.

• Melanin = dark
• So named due to the production of black pigment and black colonies.

Associated with high blood pressure.

Commonly found in severe anaerobic infections of the intestines and female reproductive/genital tract, respiratory tract, and bone infections. Found in dental plaque, mouth mucosa, tonsils. Inhibited by the presence of iron, so tends to stay in areas of low iron.

Produces hemolysin, hydrogen sulfide, ammonia, cytotoxic substances. Inhibits phagocytosis. Stimulates host immune system to produce damaging substances. Can break down the cell walls (lyse) red blood cells, mast cells, neutrophils, and other cells. Causes inflammatory response.

Hemolysin was only produced under conditions whereby iron was limited, and magnesium and calcium inhibit the reaction^{​1​​2​}.

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