Which organism is a Gram-negative bacillus that grows on BBE medium?

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Multiple Choice

Which organism is a Gram-negative bacillus that grows on BBE medium?

BBE medium is designed to isolate Bacteroides by combining bile with esculin and conditions that favor growth of certain anaerobic Gram-negative rods. Bacteroides species, including the Bacteroides fragilis group, are Gram-negative bacilli that thrive in this selective environment and hydrolyze esculin, often producing a dark coloration in the medium. This combination of bile tolerance, esculin hydrolysis, and anaerobic growth is distinctive for Bacteroides on BBE medium. The other organisms listed are typically facultative or aerobic Gram-negative rods that are not supported by this medium in the same way, so they do not grow or show the characteristic reaction on BBE. Hence, the organism that grows on BBE and is a Gram-negative bacillus is Bacteroides.

BBE medium is designed to isolate Bacteroides by combining bile with esculin and conditions that favor growth of certain anaerobic Gram-negative rods. Bacteroides species, including the Bacteroides fragilis group, are Gram-negative bacilli that thrive in this selective environment and hydrolyze esculin, often producing a dark coloration in the medium. This combination of bile tolerance, esculin hydrolysis, and anaerobic growth is distinctive for Bacteroides on BBE medium. The other organisms listed are typically facultative or aerobic Gram-negative rods that are not supported by this medium in the same way, so they do not grow or show the characteristic reaction on BBE. Hence, the organism that grows on BBE and is a Gram-negative bacillus is Bacteroides.

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