Bacteroides loescheii
Classification
Higher Order Taxa
Domain: Bacteria Phylum: Bacteroidetes Class: Bacteroidetes Order: Bacteroidales Family: Bacteroidaceae/Prevotellaceae Genus: Bacteroidales/Prevotella
Species Name: Bacteroides loescheii/Prevotella loescheii
Description and significance
Bacteroides loescheii is a gram negative, rod shaped bacterium which is found in the human mouth. It is also nonmotile, an obligate anaerobe, and does not form spores. When grown on blood agar, the colonies formed are round, convex and smooth. When incubated for longer than 48 hours, they produce a light brown pigment. This species is often found in people with oral diseases, such as gingivitis and periodontitis.
Genus Classification
When originally discovered, Bacteroides loescheii was placed in the genus Bacteroides. Since similar species such as B. melaninogenicus and B. oralis have been reexamined, and it was determined that they were different enough from other Bacteroides species to classify them in a new genus, Prevotella. The ability of these bacteria to live in our mouths is part of how they were separated from other Bacteroides species.
Cell Metabolism
B. loescheii can ferment sugars to produce succinate and acetate, though they can also produce traces of lactate and formate. Some of the sugars B. loescheii can ferment are D-fructose, D-(+)-maltose, inulin, D-(+)-mannose, D-(+)-Raffinose, starch, esculin, and cellobiose. The fact that this bacterium can use esculin and cellobiose is used to help differentiate B. loescheii from other similar species, such as B. melaninogenicus and B. denticola. B. loescheii cannot use esculin and cellobiose.
Pathology
Like similar species found in the mouth, Bacteroides loescheii can lead to gingivitis and periodontitis. It has also been reported that B. loescheii can cause subdural empyema.
Effective Antibiotics
Chloramphenicol, clindamycin, penicillin, and tetracycline are all effective against Bacteroides loescheii. Cases have been reported of B. loescheii which is resistant to metronidazole.
Current Research
This microbe has an adhesin gene which is programmed to undergo a frame-shift. The mechanism for this seems to be similar to a feature of retroviruses, which experience frame-shifts much more often than most bacteria. Cases have been found where patients develop subdural empyema caused by Bacteroides loescheii bacterium resistant to the antibiotic metronidazole.
References
1)[http://ijs.sgmjournals.org/content/32/4/399.full.pdf+html?sid=8c53d083-0b49-4b2a-af24-8eb32941c46c Holdeman, L. and Johnson, J. ““Description of Bacteroides loescheii sp. nov. and Emendation of the Descriptions of Bacteroides melaninogenicus (Oliver and Wherry) Roy and Kelly 1939 and Bacteroides denticola Shah and Collins 1981”. “International Journal of Systemic and Evolutionary Microbiology”. 2)Shah, H. and Collins, D. ““Prevotella, a New Genus To Include Bacteroides melaninogenicus and Related Species Formerly Classified in the Genus Bacteroides”. “International Journal of Systemic and Evolutionary Microbiology”.”] 3)Wu, C., Johnson, J., Moore, W., Moore, L. “”Emended Descriptions of Prevotella denticola, Prevotella loescheii, Prevotella veroralis, and Prevotella melaninogenica”. “International Journal of Systemic and Evolutionary Microbiology”.” Manch, J and London, J “”Expression of the Prevotella loescheii adhesin gene (plaA) is mediated by a programmed frameshifting hop”. “American Society for Microbiology Journal of Bacteriology”.” 4)Sweeney, L., Dave, J., Chambers, P., and Heritage, J. ““Antibiotic resistance in general dental practice—a cause for concern?”. “Journal of Antimicrobial Chemotherapy”.”
Edited by Emma Cole, student of Rachel Larsen at the University of Southern Maine
