A cervical mucosa abcess specimen was sent to the lab for culture. The culture grew an anaerobic gram-negative bacillus that was inhibitedby bile, produced a black pigment, and was negative for indole production and positive for glucose, sucrose and lactose fermentation. this organism would most likely be:

The question is incomplete as it does not have the option which are:

A. Bacteroides fragilis group

B. Bacteroides ureolyticus

C. Porphyromonas gingivalis

D. Prevotella melaninogenica

D. Prevotella melaninogenica

Explanation:

Prevotella melaninogenica is an obligate anaerobic gram-negative bacteria that generally do not cause the disease in humans but if they cause disease then they cause the disease of the neck and head.  

The bacteria are usually present in the mouth in humans and in the rumen of the sheep and cattle. The bacteria breakdown the carbohydrate source to survive and when present on the blood media produces a black pigment.  The characteristic in the question are similar to the characteristics of Prevotella melaninogenica, therefore, is the answer.