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The redefined identity of Prevotella: new implications for oral, respiratory, and vaginal health | Journal of Bacteriology
Over a century ago, Dr. William Wherry and his student, Wade Oliver, reported the isolation of a bacterium they called Bacterium melaninogenicus (1). This organism was described as a pigmented, Gram-negative, strictly anaerobic organism found frequently in the human mouth on carious teeth, but also recovered from the throat, tonsils, genitalia, and wound abscesses. Later classified under the genus Bacteroides, these and related organisms were frequently described as difficult to grow and maintain in pure culture, with biochemical assays yielding inconsistent fermentation and proteolytic profiles (2, 3). In 1947, Schwabacher, Lucas, and Rimington found that the characteristic pigments were not composed of melanin, as the name suggests, but rather hematin (4). In the 1960s, others showed that some strains required both hemin and vitamin K/vitamin K derivatives for growth (5). Consequently, as similar organisms were isolated from human oral and mucosal sites in the following decades, Shah and Collins proposed the reclassification of several species into their own genus, Prevotella, in 1990. Shah and Collins had previously argued that Bacteroides contained considerable heterogeneity, particularly with regard to fermentative capacity. They suggested that inclusion in Bacteroides should be limited only to highly fermentative species phenotypically similar to B. fragilis. The “nonsaccharolytic Bacteroides” were reclassified into the genus Porphyromonas, while the remaining 15 “moderately saccharolytic Bacteriodes” became Prevotella. Using a combination of biochemical and 16S rRNA-based analyses, they described Prevotella as organisms that may or may not produce pigment, are sensitive to bile salts, are moderately saccharolytic, and lack both glucose 6-phosphate dehydrogenase (G6PDH) and 6-phosphogluconate dehydrogenase (6PGDH) (6).
