''Prevotella melaninogenica'' is a species of bacterium in the normal microbiota of the

upper respiratory tract The respiratory tract is the subdivision of the respiratory system involved with the process of respiration in mammals. The respiratory tract is lined with respiratory epithelium as respiratory mucosa. Air is breathed in through the nose to th ...

. It is an important

human pathogen A human pathogen is a pathogen (microbe or microorganism such as a virus, bacterium, prion, or fungus) that causes disease in humans. The human physiological defense against common pathogens (such as ''Pneumocystis'') is mainly the responsibility ...

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. Microaer ...

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 oxygenate ...

. ''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 wall ...

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 bl ...

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 ''Veillonella parvula'' is a strictly anaerobic, Gram-negative, coccus-shaped bacterium in the genus ''Veillonella''. It is a normal part of the oral flora but can be associated with diseases such as periodontitis and dental caries as well as var ...

''.

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 ''Bacillu ...

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 Microbiological culture, culture microorganisms. Sometimes selective compounds are added to influence growth, such as antibiotics. Individual microorganism ...

, 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 44,00 ...

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 ''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. Unusu ...

''. 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. Unusu ...

'', 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 pneum ...

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

References

Bacteroidia Bacteria described in 1921 {{Bacteroidetes-stub