Bacteroides are a large and diverse group of Gram-negative bacteria. They are anaerobic, meaning they do not require oxygen to grow. Bacteroides are found in the human gut, where they make up a significant portion of the intestinal microbiota. They play an important role in human health, helping to digest food and synthesize vitamins. They also help protect against pathogenic bacteria by competing for space and nutrients.
Bacteroides species are typically 0.5-1 micrometers in size and have rounded or oval shapes. They are non-spore forming and motile, meaning they can move around on their own. Most species are aerobic, meaning they require oxygen to grow, but some are facultatively anaerobic, meaning they can grow without oxygen if it is present.
The most well-known member of the Bacteroides genus is Bacteroides fragilis, which is a common inhabitant of the human gastrointestinal tract. Other members of the genus include Bacteroides vulgatus, Bacteroides ovatus, and Bacteroides thetaiotaomicron.
Bacteria in the genus Bacteroides were first identified in 1897 by Japanese microbiologist Kaneyo Maruta while investigating cholera patients in Osaka. He named them after their resemblance to rod-shaped bacteria (bacteroids). The first complete description of a member of the genus was published in 1940 by American microbiologist Ralph Wolfe.*