difficile is associated with microbiota structures related to a loss of Bacteroidetes.ī. difficile, the leading cause of nosocomial infection. In addition, Bacteroidetes occupy space to optimize colonization resistance of the host against opportunistic pathogens, such as C. There is a direct link between protection from recurrent Clostridiodes difficile infection with fecal microbiota transplantation and bile salt hydrolase activity. A lower ratio of primary to secondary bile acids is associated with dysbiosis. fragilis, expresses bile salt hydrolase, which is the first step needed to convert primary conjugated to deconjugated bile acids for further metabolism to secondary bile acids. These may be reabsorbed through the large intestine and serve as an energy source for the host.įurther, B. More significantly, its colonization in the gut imparts several beneficial effects via microbiota-host and co-microbiota interactions.īacteroidetes are friendly commensals, proficient in a polysaccharide fermentation that produces a pool of short-chain fatty acids, such as acetate, butyrate, and other vital molecules.
fragilis is mostly recognized for its role in infections, yet this is an oversimplification of this species. The Good Dr Jekyll Personalities of Bacteroidetesī. These taxa play a crucial role in microbiota communities and their removal can lead to a dramatic detrimental shift in the microbiome structure and function termed “dysbiosis.” 4 Bacteroidetes is a keystone taxon however, certain conditions catalyze its conversion from itspositive Dr Jekyll attributes to its potentially negative effects, which are analogous to the famous Dr Jekyll and Mr Hyde personality switch in the 1886 Stevenson novella. The hypothesis of microbial networks highlights this co-occurrence in ecosystems, which was described in the term “keystone taxa" by Paine in 1966, in which Paine suggests that such taxa are important for the integrity and structure of communities. The relative abundance of gram-negative Bacteroidetes to other phyla, such as gram-positive Firmicutes, is essential to maintain biodiversity and human gut health, or “eubiosis,” where metabolism, immune function, and colonization resistance are in homeostasis. Fortunately, most of the time Dr Jekyll outweighs his counterpart Mr Hyde in terms of the range of ecological impact.
#GRAM NEGATIVE RODS PLUS#
These plus some other lesser understood characteristics are shown in the Figure. In this brief overview, we describe some of the key features of this keystone phylum. This discussion focuses on the 2 most-characterized species: Bacteroides fragilis and Bacteroides thetaiotaomicron. Approximately 2 dozen Bacteroides species have been identified. Several genera comprise Bacteroidetes, for example, the microbiota of the Bacteroides genus, which are gram-negative, non-spore forming, obligately anaerobic, rod-shaped bacteria. This varies depending on factors such as population, geography, age, and diet. The phylum Bacteroidetes comprises approximately 30% of the bacterial microbiota of the collective genetic content of the human gut microbiome.
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