Prevotella

NCBI:
Taxonomy
Genome:
P. intermedia 17
P. ruminicola 23

Prevotella ruminicola.Image Courtesy of TIGR.

Classification

Higher order taxa:

Bacteria; Bacteroidetes/Chlorobi group; Bacteroidetes; Bacteroidetes (class); Bacteroidales; Prevotellaceae

Species:

P. albensis; P. baroniae; P. bergensis; P. bivia; P. brevis; P. bryantii; P. buccae; P. buccalis; P. corporis; P. dentalis; P. denticola; P. disiens; P. enoeca; P. genomosp. C1; P. intermedia; P. loescheii; P. marshii; P. melaninogenica; P. multiformis; P. multisaccharivorax; P. nigrescens; P. oralis; P. oris; P.oulorum; P. pallens; P. ruminicola; P.ruminicola 23; P. aff. ruminicola Tc2-24; P. salivae; P. shahii; P. tannerae; P. veroralis; P. sp.

Description and Significance

Prevotella sp. are among the most numerous microbes culturable from the rumen and hind gut of cattle and sheep, where they help the breakdown of protein and carbohydrate foods. They are also present in humans, where they can be opportunistic pathogens. Prevotella, credited interchangably with Bacteroides melaninogenicus, has been a problem for dentists for years. As a human pathogen known for creating periodontal and tooth problems, Prevotella has long been studied in order to counteract its pathogenesis (AAP).

Genome Structure

Two strains of Prevotella have been completely sequenced: Prevotella intermedia 17 and Prevotella ruminicola 23. Both strains were sequenced by TIGR. The sequencing of these two genomes has lead to increased ability to combat Prevotella strains' pathogenic abilities.

Cell Structure and Metabolism

Prevotella intermedia. Image Courtesy of the Journal of Contemporary Dental Practice.

Prevotella strains are Gram-negative, non-motile, rod-shaped, singular cells that thrive in anaerobic growth conditions. They are known for being host-associated, colonizing the human mouth. Prevotella bacteria colonize by binding or attaching to other bacteria in addition to epithelial cells, creating a larger infection in previously infected areas. Another survival mechanism is Prevotella cells' natural antibiotic resistant genes, which prevent extermination (TIGR).

Pathology

About twenty identified species of Prevotella are known to cause infection, including Prevotella dentalis, which was previously known as Mitsuokella dentalis. Prevotella species cause infections such as abscesses, bacteraemia, wound infection, bite infections, genital tract infections, and periodontitis (Pavillion). Specific infections caused by Prevotella include the disease of tissues surrounding an individuals teeth (see photo at right) and of the supporting tooth and gingivitis (TIGR). Symptoms of Prevotella infections can include pain, swelling, and in some cases a "wet" canal (Gomes).

Antibiotics for treating Prevotella include metronidazole, amoxycillin/clavulanate, ureidopenicilins, carbapenems, cephalosporins, clindamycin, and chloramphenicol (Pavillion).

Prevotella is also well-known as a preventative agent for the bovine disease of rumen acidosis. Rumen acidosis greatly affects milk production of cattle by disrupting the typical digestive processes of the stomach. This leads to an increased susceptibility to other pathogenic forces which also affect the health of food provided from the cattle. With an estimated twenty percent of all American cattle suffering from some form of acidosis, it has been calculated that the bovine market loses one billion dollars annually (ARS).