Bacteroides
genus of bacteria
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. Unusual in bacterial organisms, Bacteroides membranes contain sphingolipids. They also contain meso-diaminopimelic acid in their peptidoglycan layer.
Bacteroides species are normally mutualistic, making up the most substantial portion of the mammalian gastrointestinal microbiota, where they play a fundamental role in processing of complex molecules to simpler ones in the host intestine. As many as 1010–1011 cells per gram of human feces have been reported. They can use simple sugars when available; however, the main sources of energy for Bacteroides species in the gut are complex host-derived and plant glycans. Studies indicate that long-term diet is strongly associated with the gut microbiome composition—those who eat a higher proportion of protein and animal fats have predominantly Bacteroides bacteria, while for those who consume more carbohydrates or fiber the Prevotella species dominate.
One of the most important clinically is Bacteroides fragilis.
The former Bacteroides melaninogenicus was reclassified and split into Prevotella melaninogenica and Prevotella intermedia.
Begin with the source’s own compact description: “Bacteroides” is genus of bacteria. The dossier treats that line as a proposition to test through Bacteroides, genus and bacteria, not as a finished interpretation.
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Stable identifiers, scientific names and standards terminology offer the best bridge between this overview and specialist evidence. The source revision retrieved here is dated Jul 19, 2026. The linked authority identifier is Q133186. None of the 0 selected statements returned an explicit reference. The first chronological checks are 1010 and 1011.
Current terminology should not be projected backward without checking the classification used when the underlying evidence was created. The source lead contains qualifying language; that uncertainty should survive quotation, summary and reuse. Authority statements aid reconciliation but still require their own references, qualifiers and ranks to be checked.
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This entry incorporates text from “Bacteroides” on English Wikipedia. Contributors are listed in the page history. Text is available under the Creative Commons Attribution-ShareAlike 4.0 License. Selected authority identifiers and statements are retrieved from Wikidata under CC0; their references and qualifiers remain part of the verification path.