Bacteroides and Prevotella

Bacteroides and Prevotella spp. belong to the Bacteroidetes phylum of Gram-negative bacteria and are among the most abundant anaerobes in the human colon and in the hindgut and rumen of farm animals. Many human Bacteroides species possess large repertoires of carbohydrate utilization genes and an ability to utilize amino acids. Growth is inhibited by mildly acidic pH in the presence of short-chain fatty acids. Pathogenic species such as Bacteroides fragilis have developed strategies to evade the host immune system. The interactions between Bacteroidetes and host defense systems and their consequences for human health should be better understood.