''Prevotella melaninogenica'' is a species of bacterium in the normal microbiota of the upper respiratory tract. It is an important human pathogen in various

anaerobic infection Anaerobic infections are caused by anaerobic bacteria. Obligately anaerobic bacteria do not grow on solid media in room air (0.04% carbon dioxide and 21% oxygen); facultatively anaerobic bacteria can grow in the presence or absence of air. Microae ...

s, often mixed with other aerobic and

anaerobic bacteria An anaerobic organism or anaerobe is any organism that does not require molecular oxygen for growth. It may react negatively or even die if free oxygen is present. In contrast, an aerobic organism (aerobe) is an organism that requires an oxygenat ...

. ''P. melaninogenica'' is an anaerobic,

Gram-negative Gram-negative bacteria are bacteria that do not retain the crystal violet stain used in the Gram staining method of bacterial differentiation. They are characterized by their cell envelopes, which are composed of a thin peptidoglycan cell wa ...

rod, named for its black colonies, and black pigment. ''P. melaninogenica'' is associated with

hypertension Hypertension (HTN or HT), also known as high blood pressure (HBP), is a long-term medical condition in which the blood pressure in the arteries is persistently elevated. High blood pressure usually does not cause symptoms. Long-term high b ...

together with ''

Campylobacter rectus ''Campylobacter rectus'' is a species of ''Campylobacter''. It is implicated as a pathogen in chronic periodontitis, which can induce bone loss. This motile bacillus is a Gram negative, facultative anaerobe. ''C. rectus'' is associated with hype ...

'' and '' Veillonella parvula''.

Description

''P. melaninogenica'' are Gram-negative

rod-shaped A bacillus (), also called a bacilliform bacterium or often just a rod (when the context makes the sense clear), is a rod-shaped bacterium or archaeon. Bacilli are found in many different taxonomic groups of bacteria. However, the name '' Baci ...

bacteria. They cannot survive in the presence of oxygen. They are not motile, and do not form spores. ''P. melaninogenica'' grow well on

blood agar An agar plate is a Petri dish that contains a growth medium solidified with agar, used to culture microorganisms. Sometimes selective compounds are added to influence growth, such as antibiotics. Individual microorganisms placed on the plate wi ...

, where they form circular dark-colored colonies that darken over one to two weeks.

History

''P. melaninogenica'' was originally described as ''Bacteroides melaninogenicus'' in 1921 by Wade Oliver and William Wherry at the

University of Cincinnati The University of Cincinnati (UC or Cincinnati) is a public research university in Cincinnati, Ohio. Founded in 1819 as Cincinnati College, it is the oldest institution of higher education in Cincinnati and has an annual enrollment of over 44,0 ...

as a new bacterium isolated from various sites of several different human patients. In 1982, Lillian Holdeman and John Johnson determined that some bacteria previously described as ''B. melaninogenicus'' were actually a distinct species, which they named '' Bacteroides loescheii''. In 1990, Haroun Shah and David Collins at the London Hospital Medical College reclassified several species of ''

Bacteroides ''Bacteroides'' is a genus of Gram-negative, obligate anaerobic bacteria. ''Bacteroides'' species are non endospore-forming bacilli, and may be either motile or nonmotile, depending on the species. The DNA base composition is 40–48% GC. Unus ...

'', including ''B. melanogenicus'' under a new genus called ''

Prevotella ''Prevotella'' is a genus of Gram-negative bacteria. ''Prevotella'' spp. are members of the oral, vaginal, and gut microbiota and are often recovered from anaerobic infections of the respiratory tract. These infections include aspiration pn ...

''. With this, ''B. melaninogenicus'' was renamed to ''Prevotella melaninogenica''.

References

Bacteroidia Bacteria described in 1921 {{Bacteroidetes-stub